xref: /libcore/harmony-tests/src/test/java/org/apache/harmony/tests/java/util/prefs/AbstractPreferencesTest.java

/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package org.apache.harmony.tests.java.util.prefs;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.prefs.AbstractPreferences;
import java.util.prefs.BackingStoreException;
import java.util.prefs.FilePreferencesImpl;
import java.util.prefs.NodeChangeEvent;
import java.util.prefs.NodeChangeListener;
import java.util.prefs.PreferenceChangeEvent;
import java.util.prefs.PreferenceChangeListener;
import java.util.prefs.Preferences;
import java.util.prefs.PreferencesFactory;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import junit.framework.TestCase;
import libcore.io.IoUtils;
import org.w3c.dom.Document;
import org.xml.sax.SAXException;

public class AbstractPreferencesTest extends TestCase {

    public static final class TestPreferencesFactory implements PreferencesFactory {
        private final Preferences userPrefs;
        private final Preferences systemPrefs;

        public TestPreferencesFactory(String root) {
            userPrefs = new FilePreferencesImpl(root + "/user", true);
            systemPrefs = new FilePreferencesImpl(root + "/system", false);
        }

        public Preferences userRoot() {
            return userPrefs;
        }

        public Preferences systemRoot() {
            return systemPrefs;
        }
    }

    private AbstractPreferences pref;
    private AbstractPreferences root;
    private AbstractPreferences parent;
    private PreferencesFactory defaultFactory;

    private final static String LONG_KEY;
    private final static String LONG_VALUE;
    private final static String LONG_NAME;

    static {
        final byte[] chars = new byte[Preferences.MAX_VALUE_LENGTH];

        LONG_VALUE = new String(chars, StandardCharsets.US_ASCII);
        LONG_KEY = LONG_VALUE.substring(0, Preferences.MAX_KEY_LENGTH);
        LONG_NAME = LONG_VALUE.substring(0, Preferences.MAX_NAME_LENGTH);
    }

    @Override
    protected void setUp() throws Exception {
        File tmpDir = IoUtils.createTemporaryDirectory("OldAbstractPreferencesTest");
        defaultFactory = Preferences.setPreferencesFactory(
                new TestPreferencesFactory(tmpDir.getAbsolutePath()));
        root = (AbstractPreferences) Preferences.userRoot();
        parent = (AbstractPreferences) Preferences.userNodeForPackage(Preferences.class);

        pref = (AbstractPreferences) parent.node("mock");
    }

    @Override
    protected void tearDown() throws Exception {
        Preferences.setPreferencesFactory(defaultFactory);
    }

    public void testConstructor() throws BackingStoreException {
        try {
            pref = new MockAbstractPreferences(
                    (AbstractPreferences) Preferences.userRoot(), "mo/ck");
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }
        try {
            pref = new MockAbstractPreferences(null, "mock");
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }
        try {
            new MockAbstractPreferences(null, " ");
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }
        try {
            new MockAbstractPreferences(pref, "");
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }
        try {
            new MockAbstractPreferences(pref, null);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        if (!(pref instanceof MockAbstractPreferences)) {
            return;
        }
        new MockAbstractPreferences(pref, " ");

        Preferences p2 = new MockAbstractPreferences(null, "");
        assertNotSame(p2, Preferences.systemRoot());
        assertNotSame(p2, Preferences.userRoot());
        assertFalse(p2.isUserNode());

        p2 = new MockAbstractPreferences((AbstractPreferences) Preferences
                .userRoot(), "mock");
        assertNotSame(p2, pref);
        p2.removeNode();
    }

    public void testProtectedFields() throws BackingStoreException {
        if (!(pref instanceof MockAbstractPreferences)) {
            return;
        }
        MockAbstractPreferences p = new MockAbstractPreferences(pref, "newNode");
        assertFalse(p.getNewNode());
        assertSame(p.getLock().getClass(), Object.class);

        p = (MockAbstractPreferences) pref.node("child");
        assertTrue(p.getNewNode());

        p = (MockAbstractPreferences) ((MockAbstractPreferences) pref)
                .publicChildSpi("child2");
        assertTrue(p.getNewNode());
    }

    public void testToString() {
        assertEquals("User Preference Node: " + pref.absolutePath(), pref
                .toString());

        pref = new MockAbstractPreferences((AbstractPreferences) Preferences
                .systemRoot(), "mock");
        assertEquals("System Preference Node: " + pref.absolutePath(), pref
                .toString());
    }

    public void testAbsolutePath() {
        assertEquals("/java/util/prefs/mock", pref.absolutePath());

        pref = new MockAbstractPreferences(pref, " ");
        assertEquals("/java/util/prefs/mock/ ", pref.absolutePath());
    }

    public void testChildrenNames() throws BackingStoreException {
        assertEquals(0, pref.childrenNames().length);

        // MockAbstractPreferences child1 = new MockAbstractPreferences(pref,
        // "child1");
        // MockAbstractPreferences child2 = new MockAbstractPreferences(pref,
        // "child2");
        // MockAbstractPreferences child3 = new MockAbstractPreferences(pref,
        // "child3");
        // MockAbstractPreferences subchild1 = new
        // MockAbstractPreferences(child1,
        // "subchild1");
        Preferences child1 = pref.node("child1");

        pref.node("child2");
        pref.node("child3");
        child1.node("subchild1");

        assertSame(pref, child1.parent());
        assertEquals(3, pref.childrenNames().length);
    }

    public void testClear() throws BackingStoreException {
        pref.put("testClearKey", "testClearValue");
        pref.put("testClearKey1", "testClearValue1");
        assertEquals("testClearValue", pref.get("testClearKey", null));
        assertEquals("testClearValue1", pref.get("testClearKey1", null));
        pref.clear();
        assertNull(pref.get("testClearKey", null));
        assertNull(pref.get("testClearKey1", null));
    }

    public void testGet() throws BackingStoreException {
        assertNull(pref.get("", null));
        assertEquals("default", pref.get("key", "default"));
        assertNull(pref.get("key", null));
        pref.put("testGetkey", "value");
        assertNull(pref.get("testGetKey", null));
        assertEquals("value", pref.get("testGetkey", null));

        try {
            pref.get(null, "abc");
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }

        pref.get("", "abc");
        pref.get("key", null);
        pref.get("key", "");
        pref.putFloat("floatKey", 1.0f);
        assertEquals("1.0", pref.get("floatKey", null));

        pref.removeNode();
        try {
            pref.get("key", "abc");
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.get(null, "abc");
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
    }

    public void testGetBoolean() {
        try {
            pref.getBoolean(null, false);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }

        pref.put("testGetBooleanKey", "false");
        pref.put("testGetBooleanKey2", "value");
        assertFalse(pref.getBoolean("testGetBooleanKey", true));
        assertTrue(pref.getBoolean("testGetBooleanKey2", true));
    }

    public void testPutByteArray() {
        try {
            pref.putByteArray(null, new byte[0]);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            pref.putByteArray("testPutByteArrayKey4", null);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }

        pref.putByteArray(LONG_KEY, new byte[0]);
        try {
            pref.putByteArray(LONG_KEY + "a", new byte[0]);
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }
        byte[] longArray = new byte[(int) (Preferences.MAX_VALUE_LENGTH * 0.74)];
        byte[] longerArray = new byte[(int) (Preferences.MAX_VALUE_LENGTH * 0.75) + 1];
        pref.putByteArray(LONG_KEY, longArray);
        try {
            pref.putByteArray(LONG_KEY, longerArray);
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }

        pref.putByteArray("testPutByteArrayKey", new byte[0]);
        assertEquals("", pref.get("testPutByteArrayKey", null));
        assertTrue(Arrays.equals(new byte[0], pref.getByteArray(
                "testPutByteArrayKey", null)));

        pref.putByteArray("testPutByteArrayKey3", new byte[] { 'a', 'b', 'c' });
        assertEquals("YWJj", pref.get("testPutByteArrayKey3", null));
        assertTrue(Arrays.equals(new byte[] { 'a', 'b', 'c' }, pref
                .getByteArray("testPutByteArrayKey3", null)));
    }

    public void testGetByteArray() throws UnsupportedEncodingException {
        try {
            pref.getByteArray(null, new byte[0]);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        byte[] b64Array = new byte[] { 0x59, 0x57, 0x4a, 0x6a };// BASE64
        // encoding for
        // "abc"

        pref.put("testGetByteArrayKey", "abc=");
        pref.put("testGetByteArrayKey2", new String(b64Array, "UTF-8"));
        pref.put("invalidKey", "<>?");
        // assertTrue(Arrays.equals(new byte[0], p.getByteArray(
        // "testGetByteArrayKey", new byte[0])));
        assertTrue(Arrays.equals(new byte[] { 105, -73 }, pref.getByteArray(
                "testGetByteArrayKey", new byte[0])));
        assertTrue(Arrays.equals(new byte[] { 'a', 'b', 'c' }, pref
                .getByteArray("testGetByteArrayKey2", new byte[0])));
        assertTrue(Arrays.equals(new byte[0], pref.getByteArray("invalidKey",
                new byte[0])));

        pref.putByteArray("testGetByteArrayKey3", b64Array);
        pref.putByteArray("testGetByteArrayKey4", "abc".getBytes());
        assertTrue(Arrays.equals(b64Array, pref.getByteArray(
                "testGetByteArrayKey3", new byte[0])));
        assertTrue(Arrays.equals("abc".getBytes(), pref.getByteArray(
                "testGetByteArrayKey4", new byte[0])));
    }

    public void testGetDouble() {
        try {
            pref.getDouble(null, 0);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }

        pref.put("testGetDoubleKey", "1");
        pref.put("testGetDoubleKey2", "value");
        pref.putDouble("testGetDoubleKey3", 1);
        pref.putInt("testGetDoubleKey4", 1);
        assertEquals(1.0, pref.getDouble("testGetDoubleKey", 0.0), 0);
        assertEquals(0.0, pref.getDouble("testGetDoubleKey2", 0.0), 0);
        assertEquals(1.0, pref.getDouble("testGetDoubleKey3", 0.0), 0);
        assertEquals(1.0, pref.getDouble("testGetDoubleKey4", 0.0), 0);
    }

    public void testGetFloat() {
        try {
            pref.getFloat(null, 0f);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        pref.put("testGetFloatKey", "1");
        pref.put("testGetFloatKey2", "value");
        assertEquals(1f, pref.getFloat("testGetFloatKey", 0f), 0); //$NON-NLS-1$
        assertEquals(0f, pref.getFloat("testGetFloatKey2", 0f), 0);
    }

    public void testGetInt() {
        try {
            pref.getInt(null, 0);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }

        pref.put("testGetIntKey", "1");
        pref.put("testGetIntKey2", "value");
        assertEquals(1, pref.getInt("testGetIntKey", 0));
        assertEquals(0, pref.getInt("testGetIntKey2", 0));
    }

    public void testGetLong() {
        try {
            pref.getLong(null, 0);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }

        pref.put("testGetLongKey", "1");
        pref.put("testGetLongKey2", "value");
        assertEquals(1, pref.getInt("testGetLongKey", 0));
        assertEquals(0, pref.getInt("testGetLongKey2", 0));
    }

    public void testIsUserNode() {
        assertTrue(pref.isUserNode());

        pref = new MockAbstractPreferences((AbstractPreferences) Preferences
                .systemRoot(), "mock");
        assertFalse(pref.isUserNode());
    }

    // TODO, how to test the "stored defaults"
    // TODO, how to test the multi-thread
    public void testKeys() throws BackingStoreException {
        assertEquals(0, pref.keys().length);

        pref.put("key0", "value");
        pref.put("key1", "value1");
        pref.put("key2", "value2");
        pref.put("key3", "value3");

        String[] keys = pref.keys();
        assertEquals(4, keys.length);
        for (int i = 0; i < keys.length; i++) {
            assertEquals(0, keys[i].indexOf("key"));
            assertEquals(4, keys[i].length());
        }
    }

    public void testName() {
        assertEquals("mock", pref.name());

        pref = new MockAbstractPreferences(pref, " ");
        assertEquals(" ", pref.name());
    }

    public void testCharCase() throws BackingStoreException {
        assertSame(pref.node("samechild"), pref.node("samechild"));
        assertNotSame(pref.node("sameChild"), pref.node("samechild"));
        assertNotSame(pref.node("child"), pref.node("Child"));
        assertNotSame(pref.node("child"), pref.node("Child"));
        assertNotSame(pref.node("child"), pref.node(" child"));
        String[] names = pref.childrenNames();
        assertEquals(5, names.length);
        for (int i = 0; i < names.length; i++) {
            String name = names[i];
            assertTrue("samechild".equals(name) || "sameChild".equals(name)
                    || "child".equals(name) || "Child".equals(name)
                    || " child".equals(name));
        }

        Preferences mock1 = pref.node("mock1");
        mock1.put("key", "1value");
        mock1.put("KEY", "2value");
        mock1.put("/K/E/Y", "7value");
        mock1.put("/K/E\\Y\\abc~@!#$%^&*(\\", "8value");

        assertEquals("8value", mock1.get("/K/E\\Y\\abc~@!#$%^&*(\\", null));
        assertNull(mock1.get("/k/e/y", null));
        assertEquals("7value", mock1.get("/K/E/Y", null));
        assertEquals("1value", mock1.get("key", null));

        String[] keys = mock1.keys();
        assertEquals(4, keys.length);
        for (int i = 0; i < keys.length; i++) {
            String key = keys[i];
            assertTrue("key".equals(key) || "KEY".equals(key)
                    || "/K/E/Y".equals(key)
                    || "/K/E\\Y\\abc~@!#$%^&*(\\".equals(key));
        }
    }

    public void testNode() throws BackingStoreException {
        try {
            pref.node(null);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            pref.node("/java/util/prefs/");
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }
        try {
            pref.node("/java//util/prefs");
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }
        try {
            pref.node(LONG_NAME + "a");
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }
        assertNotNull(pref.node(LONG_NAME));

        assertSame(root, pref.node("/"));

        Preferences prefs = pref.node("/java/util/prefs");
        assertSame(prefs, parent);

        assertSame(pref, pref.node(""));

        if (!(pref instanceof MockAbstractPreferences)) {
            return;
        }
        MockAbstractPreferences child = (MockAbstractPreferences) ((MockAbstractPreferences) pref)
                .publicChildSpi("child");
        assertSame(child, pref.node("child"));

        Preferences child2 = pref.node("child2");
        assertSame(child2, ((MockAbstractPreferences) pref)
                .publicChildSpi("child2"));

        Preferences grandchild = pref.node("child/grandchild");
        assertSame(grandchild, child.childSpi("grandchild"));
        assertSame(grandchild, child.cachedChildrenImpl()[0]);
        grandchild.removeNode();
        assertNotSame(grandchild, pref.node("child/grandchild"));

        grandchild = pref.node("child3/grandchild");
        AbstractPreferences[] childs = ((MockAbstractPreferences) pref)
                .cachedChildrenImpl();
        Preferences child3 = child;
        for (int i = 0; i < childs.length; i++) {
            if (childs[i].name().equals("child3")) {
                child3 = childs[i];
                break;
            }
        }
        assertSame(child3, grandchild.parent());
    }

    public void testNodeExists() throws BackingStoreException {
        try {
            pref.nodeExists(null);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            pref.nodeExists("/java/util/prefs/");
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }
        try {
            pref.nodeExists("/java//util/prefs");
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }

        assertTrue(pref.nodeExists("/"));

        assertTrue(pref.nodeExists("/java/util/prefs"));

        assertTrue(pref.nodeExists(""));

        assertFalse(pref.nodeExists("child"));
        Preferences grandchild = pref.node("child/grandchild");
        assertTrue(pref.nodeExists("child"));
        assertTrue(pref.nodeExists("child/grandchild"));
        grandchild.removeNode();
        assertTrue(pref.nodeExists("child"));
        assertFalse(pref.nodeExists("child/grandchild"));
        assertFalse(grandchild.nodeExists(""));

        assertFalse(pref.nodeExists("child2/grandchild"));
        pref.node("child2/grandchild");
        assertTrue(pref.nodeExists("child2/grandchild"));
    }

    public void test_nodeExists() throws BackingStoreException {
        AbstractPreferences test = (AbstractPreferences) Preferences.userRoot()
                .node("test");
        try {
            test.nodeExists(null);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }

        test.removeNode();
        try {
            test.nodeExists(null);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
    }

    public void testParent() {
        assertSame(parent, pref.parent());
        AbstractPreferences child1 = new MockAbstractPreferences(pref, "child1");
        assertSame(pref, child1.parent());
        assertNull(root.parent());
    }

    public void testPut() throws BackingStoreException {
        pref.put("", "emptyvalue");
        assertEquals("emptyvalue", pref.get("", null));
        pref.put("testPutkey", "value1");
        assertEquals("value1", pref.get("testPutkey", null));
        pref.put("testPutkey", "value2");
        assertEquals("value2", pref.get("testPutkey", null));

        pref.put("", "emptyvalue");
        assertEquals("emptyvalue", pref.get("", null));

        try {
            pref.put(null, "value");
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }

        try {
            pref.put("key", null);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }

        pref.put(LONG_KEY, LONG_VALUE);
        try {
            pref.put(LONG_KEY + 1, LONG_VALUE);
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }

        try {
            pref.put(LONG_KEY, LONG_VALUE + 1);
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }

        pref.removeNode();
        try {
            pref.put(LONG_KEY, LONG_VALUE + 1);
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }

        try {
            pref.put(LONG_KEY, LONG_VALUE);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
    }

    public void testPutBoolean() {
        try {
            pref.putBoolean(null, false);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }

        pref.putBoolean(LONG_KEY, false);
        try {
            pref.putBoolean(LONG_KEY + "a", false);
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }

        pref.putBoolean("testPutBooleanKey", false);
        assertEquals("false", pref.get("testPutBooleanKey", null));
        assertFalse(pref.getBoolean("testPutBooleanKey", true));
    }

    public void testPutDouble() {
        try {
            pref.putDouble(null, 3);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }

        pref.putDouble(LONG_KEY, 3);
        try {
            pref.putDouble(LONG_KEY + "a", 3);
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }

        pref.putDouble("testPutDoubleKey", 3);
        assertEquals("3.0", pref.get("testPutDoubleKey", null));
        assertEquals(3, pref.getDouble("testPutDoubleKey", 0), 0);
    }

    public void testPutFloat() {
        try {
            pref.putFloat(null, 3f);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }

        pref.putFloat(LONG_KEY, 3f);
        try {
            pref.putFloat(LONG_KEY + "a", 3f);
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }

        pref.putFloat("testPutFloatKey", 3f);
        assertEquals("3.0", pref.get("testPutFloatKey", null));
        assertEquals(3f, pref.getFloat("testPutFloatKey", 0), 0);
    }

    public void testPutInt() {
        try {
            pref.putInt(null, 3);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }

        pref.putInt(LONG_KEY, 3);
        try {
            pref.putInt(LONG_KEY + "a", 3);
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }

        pref.putInt("testPutIntKey", 3);
        assertEquals("3", pref.get("testPutIntKey", null));
        assertEquals(3, pref.getInt("testPutIntKey", 0));
    }

    public void testPutLong() {
        try {
            pref.putLong(null, 3L);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }

        pref.putLong(LONG_KEY, 3L);
        try {
            pref.putLong(LONG_KEY + "a", 3L);
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }

        pref.putLong("testPutLongKey", 3L);
        assertEquals("3", pref.get("testPutLongKey", null));
        assertEquals(3L, pref.getLong("testPutLongKey", 0));
    }

    public void testRemove() throws BackingStoreException {
        pref.remove("key");

        pref.put("key", "value");
        assertEquals("value", pref.get("key", null));
        pref.remove("key");
        assertNull(pref.get("key", null));

        pref.remove("key");

        try {
            pref.remove(null);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }

        pref.removeNode();
        try {
            pref.remove("key");
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
    }

    public void testRemoveNode() throws BackingStoreException {
        Preferences child = pref.node("child");
        Preferences child1 = pref.node("child1");
        Preferences grandchild = child.node("grandchild");

        pref.removeNode();

        assertFalse(child.nodeExists(""));
        assertFalse(child1.nodeExists(""));
        assertFalse(grandchild.nodeExists(""));
        assertFalse(pref.nodeExists(""));
    }

    public void testRemoveNodeChangeListener() {
        try {
            pref.removeNodeChangeListener(null);
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }

        MockNodeChangeListener l1 = new MockNodeChangeListener();
        MockNodeChangeListener l2 = new MockNodeChangeListener();
        pref.addNodeChangeListener(l1);
        pref.addNodeChangeListener(l1);

        pref.removeNodeChangeListener(l1);
        pref.removeNodeChangeListener(l1);
        try {
            pref.removeNodeChangeListener(l1);
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }

        try {
            pref.removeNodeChangeListener(l2);
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }
    }

    public void testRemovePreferenceChangeListener() {
        try {
            pref.removePreferenceChangeListener(null);
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }
        MockPreferenceChangeListener l1 = new MockPreferenceChangeListener();
        MockPreferenceChangeListener l2 = new MockPreferenceChangeListener();
        pref.addPreferenceChangeListener(l1);
        pref.addPreferenceChangeListener(l1);
        try {
            pref.removePreferenceChangeListener(l2);
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }
        pref.removePreferenceChangeListener(l1);
        pref.removePreferenceChangeListener(l1);
        try {
            pref.removePreferenceChangeListener(l1);
            fail("should throw IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
        }
    }

    public void testSync() throws BackingStoreException {
        pref.sync();
        if (!(pref instanceof MockAbstractPreferences)) {
            return;
        }
        MockAbstractPreferences p = (MockAbstractPreferences) pref;
        p.resetSyncTimes();
        p.sync();
        assertEquals(1, p.getSyncTimes());

        p.resetSyncTimes();
        MockAbstractPreferences child = (MockAbstractPreferences) p
                .node("child");
        MockAbstractPreferences child2 = new MockAbstractPreferences(p,
                "child2");
        p.childs.put("child2", child2);
        assertEquals(1, p.cachedChildrenImpl().length);
        assertSame(child, p.cachedChildrenImpl()[0]);
        p.sync();
        assertEquals(1, p.getSyncTimes());
        assertEquals(1, child.getSyncTimes());
        assertEquals(0, child2.getSyncTimes());

        p.resetSyncTimes();
        child.resetSyncTimes();
        child.sync();
        assertEquals(0, p.getSyncTimes());
        assertEquals(1, child.getSyncTimes());

        p.resetSyncTimes();
        child.resetSyncTimes();
        MockAbstractPreferences grandson = (MockAbstractPreferences) child
                .node("grandson");
        child.sync();
        assertEquals(0, p.getSyncTimes());
        assertEquals(1, child.getSyncTimes());
        assertEquals(1, grandson.getSyncTimes());
    }

    public void testFlush() throws BackingStoreException {
        pref.flush();
        if (!(pref instanceof MockAbstractPreferences)) {
            return;
        }
        MockAbstractPreferences p = (MockAbstractPreferences) pref;
        p.resetFlushedTimes();
        p.flush();
        assertEquals(1, p.getFlushedTimes());

        p.resetFlushedTimes();
        MockAbstractPreferences child = (MockAbstractPreferences) p
                .node("child");
        MockAbstractPreferences child2 = new MockAbstractPreferences(p,
                "child2");
        p.childs.put("child2", child2);
        assertEquals(1, p.cachedChildrenImpl().length);
        assertSame(child, p.cachedChildrenImpl()[0]);
        p.flush();
        assertEquals(1, p.getFlushedTimes());
        assertEquals(1, child.getFlushedTimes());
        assertEquals(0, child2.getFlushedTimes());

        p.resetFlushedTimes();
        child.resetFlushedTimes();
        child.flush();
        assertEquals(0, p.getFlushedTimes());
        assertEquals(1, child.getFlushedTimes());

        p.resetFlushedTimes();
        child.resetFlushedTimes();
        MockAbstractPreferences grandson = (MockAbstractPreferences) child
                .node("grandson");
        child.flush();
        assertEquals(0, p.getFlushedTimes());
        assertEquals(1, child.getFlushedTimes());
        assertEquals(1, grandson.getFlushedTimes());

        p.resetFlushedTimes();
        child.resetFlushedTimes();
        grandson.resetFlushedTimes();
        child.removeNode();
        child.flush();
        assertEquals(0, p.getFlushedTimes());
        assertEquals(1, child.getFlushedTimes());
        assertEquals(0, grandson.getFlushedTimes());
    }

    public void testGetChild() throws BackingStoreException {
        if (!(pref instanceof MockAbstractPreferences)) {
            return;
        }
        MockAbstractPreferences p = (MockAbstractPreferences) pref;
        assertNull(p.getChildImpl("child"));
        MockAbstractPreferences child = new MockAbstractPreferences(p, "child");
        p.childs.put("child", child);
        assertSame(child, p.getChildImpl("child"));
        assertNull(p.getChildImpl("child "));

        assertNull(p.getChildImpl("child/grandson"));
        child.childs.put("grandson", new MockAbstractPreferences(child,
                "grandson"));
        assertNull(p.getChildImpl("child/grandson"));

        assertNull(p.getChildImpl(null));
        assertNull(p.getChildImpl(""));
        assertNull(p.getChildImpl(" "));
        assertNull(p.getChildImpl("abc//abc"));
        assertNull(p.getChildImpl("child/"));
        assertNull(p.getChildImpl(LONG_NAME + "a"));

        child.removeNode();
        assertNull(p.getChildImpl("child"));
    }

    public void testIsRemoved() throws BackingStoreException {
        if (!(pref instanceof MockAbstractPreferences)) {
            return;
        }
        MockAbstractPreferences p = (MockAbstractPreferences) pref;
        assertFalse(p.isRemovedImpl());
        p.removeNode();
        assertTrue(p.isRemovedImpl());
    }

    public void testExportNode() throws Exception {
        try {
            pref.exportNode(null);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }

        pref.putBoolean("key", false);
        Preferences child = pref.node("child<");
        child.put("key2", "value2<");
        Preferences grandson = child.node("grandson");
        grandson.put("key3", "value3");
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        child.exportNode(out);

        byte[] result = out.toByteArray();
        ByteArrayInputStream in = new ByteArrayInputStream(result);

        parseXmlStream(in, false);
    }

    private static Document parseXmlStream(InputStream input, boolean validating)
            throws SAXException, IOException, ParserConfigurationException {
        // Create a builder factory
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        factory.setValidating(validating);
        // Create the builder and parse the file
        DocumentBuilder builder = factory.newDocumentBuilder();
        return builder.parse(input);
    }

    public void testExportSubtree() throws Exception {
        try {
            pref.exportSubtree(null);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }

        ByteArrayOutputStream out = new ByteArrayOutputStream();
        pref.putBoolean("key", false);
        Preferences child = pref.node("child");
        child.put("key2", "value2");
        Preferences grandson = child.node("grandson");
        grandson.put("key3", "value3");
        child.node("grandson2");
        Preferences grandgrandson = grandson.node("grandgrandson");
        grandgrandson.put("key4", "value4");
        child.exportSubtree(out);

        byte[] result = out.toByteArray();
        ByteArrayInputStream in = new ByteArrayInputStream(result);

        // We don't have an xpath API so all we can do is test that the
        // generated XML parses correctly.
        parseXmlStream(in, false);
    }

    public void testCachedChildren() throws Exception {
        if (!(pref instanceof MockAbstractPreferences)) {
            return;
        }
        MockAbstractPreferences p = (MockAbstractPreferences) pref;
        assertEquals(0, p.cachedChildrenImpl().length);

        MockAbstractPreferences child = (MockAbstractPreferences) p
                .getChildImpl("child");
        assertNull(child);

        child = new MockAbstractPreferences(p, "child");
        assertSame(child, p.getChildImpl("child"));

        assertEquals(0, p.cachedChildrenImpl().length);

        p.node("child");
        assertSame(child, p.cachedChildrenImpl()[0]);

        MockAbstractPreferences grandchild = new MockAbstractPreferences(child,
                "grandchild");
        assertSame(grandchild, child.getChildImpl("grandchild"));
        assertNull(p.getChildImpl("grandchild"));

        assertEquals(1, p.cachedChildrenImpl().length);
        assertEquals(0, child.cachedChildrenImpl().length);

        p.node("child/grandchild");
        assertSame(child, p.cachedChildrenImpl()[0]);
        assertSame(grandchild, child.cachedChildrenImpl()[0]);
        assertEquals(1, p.cachedChildrenImpl().length);
        assertEquals(1, child.cachedChildrenImpl().length);

        p.childs.put("child2", new MockAbstractPreferences(p, "child2"));
        p.nodeExists("child2/grandchild");
        assertSame(child, p.cachedChildrenImpl()[0]);
        assertSame(grandchild, child.cachedChildrenImpl()[0]);
        assertEquals(1, p.cachedChildrenImpl().length);
        assertEquals(1, child.cachedChildrenImpl().length);
    }

    public void testAbstractMethod() {
        if (!(pref instanceof MockAbstractPreferences)) {
            return;
        }
        ((MockAbstractPreferences) pref).protectedAbstractMethod();
    }

    public void testBackingStoreException() throws IOException,
            BackingStoreException {
        if (!(pref instanceof MockAbstractPreferences)) {
            return;
        }
        MockAbstractPreferences p = (MockAbstractPreferences) pref;
        p.setResult(MockAbstractPreferences.backingException);
        try {
            p.childrenNames();
            fail("should throw BackingStoreException");
        } catch (BackingStoreException e) {
        }
        p.put("exceptionkey", "value");
        p.absolutePath();
        p.toString();
        assertEquals("exception default", p.get("key", "exception default"));
        p.remove("key");
        try {
            p.clear();
            fail("should throw BackingStoreException");
        } catch (BackingStoreException expected) {
        }

        p.putInt("key", 3);
        p.getInt("key", 3);
        p.putLong("key", 3l);
        p.getLong("key", 3l);
        p.putDouble("key", 3);
        p.getDouble("key", 3);
        p.putBoolean("key", true);
        p.getBoolean("key", true);
        p.putFloat("key", 3f);
        p.getFloat("key", 3f);
        p.putByteArray("key", new byte[0]);
        p.getByteArray("key", new byte[0]);
        try {
            p.keys();
            fail("should throw BackingStoreException");
        } catch (BackingStoreException expected) {
        }

        try {
            p.keys();
            fail("should throw BackingStoreException");
        } catch (BackingStoreException expected) {
        }
        try {
            p.childrenNames();
            fail("should throw BackingStoreException");
        } catch (BackingStoreException expected) {
        }
        p.parent();
        p.node("");
        p.nodeExists("");
        try {
            p.removeNode();
            fail("should throw BackingStoreException");
        } catch (BackingStoreException expected) {
        }
        p.name();
        p.absolutePath();
        p.isUserNode();
        MockPreferenceChangeListener mockPreferenceChangeListener = new MockPreferenceChangeListener();
        p.addPreferenceChangeListener(mockPreferenceChangeListener);
        p.removePreferenceChangeListener(mockPreferenceChangeListener);
        MockNodeChangeListener mockNodeChangeListener = new MockNodeChangeListener();
        p.addNodeChangeListener(mockNodeChangeListener);
        p.removeNodeChangeListener(mockNodeChangeListener);
        p.toString();
        try {
            p.sync();
            fail("should throw BackingStoreException");
        } catch (BackingStoreException expected) {
        }
        try {
            p.flush();
            fail("should throw BackingStoreException");
        } catch (BackingStoreException expected) {
        }
        try {
            p.exportNode(new ByteArrayOutputStream());
            fail("should throw BackingStoreException");
        } catch (BackingStoreException expected) {
        }
        try {
            p.exportSubtree(new ByteArrayOutputStream());
            fail("should throw BackingStoreException");
        } catch (BackingStoreException expected) {
        }
        p.isRemovedImpl();
        try {
            p.getChildImpl(null);
            fail("should throw BackingStoreException");
        } catch (BackingStoreException expected) {
        }
        p.cachedChildrenImpl();
    }

    public void testRuntimeException() throws IOException,
            BackingStoreException {
        if (!(pref instanceof MockAbstractPreferences)) {
            return;
        }
        MockAbstractPreferences p = (MockAbstractPreferences) pref;
        p.setResult(MockAbstractPreferences.runtimeException);
        try {
            p.childrenNames();
            fail("should throw MockRuntimeException");
        } catch (MockRuntimeException expected) {
        }
        try {
            p.put("exceptionkey", "value");
            fail("should throw MockRuntimeException");
        } catch (MockRuntimeException expected) {
        }
        p.absolutePath();
        p.toString();
        assertEquals("exception default", p.get("key", "exception default"));
        try {
            p.remove("key");
            fail("should throw MockRuntimeException");
        } catch (MockRuntimeException expected) {
        }
        try {
            p.clear();
            fail("should throw MockRuntimeException");
        } catch (MockRuntimeException expected) {
        }
        try {
            p.putInt("key", 3);
            fail("should throw MockRuntimeException");
        } catch (MockRuntimeException expected) {
        }
        p.getInt("key", 3);
        try {
            p.putLong("key", 3l);
            fail("should throw MockRuntimeException");
        } catch (MockRuntimeException expected) {
        }
        p.getLong("key", 3l);
        try {
            p.putDouble("key", 3);
            fail("should throw MockRuntimeException");
        } catch (MockRuntimeException expected) {
        }
        p.getDouble("key", 3);
        try {
            p.putBoolean("key", true);
            fail("should throw MockRuntimeException");
        } catch (MockRuntimeException expected) {
        }
        p.getBoolean("key", true);
        try {
            p.putFloat("key", 3f);
            fail("should throw MockRuntimeException");
        } catch (MockRuntimeException expected) {
        }
        p.getFloat("key", 3f);
        try {
            p.putByteArray("key", new byte[0]);
            fail("should throw MockRuntimeException");
        } catch (MockRuntimeException expected) {
        }
        p.getByteArray("key", new byte[0]);
        try {
            p.keys();
            fail("should throw MockRuntimeException");
        } catch (MockRuntimeException expected) {
        }
        try {
            p.keys();
            fail("should throw MockRuntimeException");
        } catch (MockRuntimeException expected) {
        }
        try {
            p.childrenNames();
            fail("should throw MockRuntimeException");
        } catch (MockRuntimeException expected) {
        }
        p.parent();
        p.node("");
        p.nodeExists("");
        try {
            p.removeNode();
            fail("should throw MockRuntimeException");
        } catch (MockRuntimeException expected) {
        }
        p.name();
        p.absolutePath();
        p.isUserNode();
        MockPreferenceChangeListener pcl = new MockPreferenceChangeListener();
        p.addPreferenceChangeListener(pcl);
        p.removePreferenceChangeListener(pcl);
        MockNodeChangeListener ncl = new MockNodeChangeListener();
        p.addNodeChangeListener(ncl);
        p.removeNodeChangeListener(ncl);
        p.toString();
        try {
            p.sync();
            fail("should throw MockRuntimeException");
        } catch (MockRuntimeException expected) {
        }
        try {
            p.flush();
            fail("should throw MockRuntimeException");
        } catch (MockRuntimeException expected) {
        }
        try {
            p.exportNode(new ByteArrayOutputStream());
            fail("should throw MockRuntimeException");
        } catch (MockRuntimeException expected) {
        }
        try {
            p.exportSubtree(new ByteArrayOutputStream());
            fail("should throw MockRuntimeException");
        } catch (MockRuntimeException expected) {
        }
        p.isRemovedImpl();
        try {
            p.getChildImpl(null);
            fail("should throw MockRuntimeException");
        } catch (MockRuntimeException expected) {
        }
        p.cachedChildrenImpl();
    }

    public void testSPIReturnNull() throws IOException, BackingStoreException {
        if (!(pref instanceof MockAbstractPreferences)) {
            return;
        }
        MockAbstractPreferences p = (MockAbstractPreferences) pref;
        p.setResult(MockAbstractPreferences.returnNull);
        try {
            p.childrenNames();
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        p.absolutePath();
        p.toString();
        p.put("nullkey", "value");
        assertEquals("null default", p.get("key", "null default"));
        p.remove("key");
        try {
            p.clear();
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        p.putInt("key", 3);
        p.getInt("key", 3);
        p.putLong("key", 3l);
        p.getLong("key", 3l);
        p.putDouble("key", 3);
        p.getDouble("key", 3);
        p.putBoolean("key", true);
        p.getBoolean("key", true);
        p.putFloat("key", 3f);
        p.getFloat("key", 3f);
        p.putByteArray("key", new byte[0]);
        p.getByteArray("key", new byte[0]);
        p.keys();
        try {
            p.childrenNames();
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        p.parent();
        p.node("");
        p.nodeExists("");
        try {
            p.removeNode();
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        p.name();
        p.absolutePath();
        p.isUserNode();
        MockPreferenceChangeListener mockPreferenceChangeListener = new MockPreferenceChangeListener();
        p.addPreferenceChangeListener(mockPreferenceChangeListener);
        p.removePreferenceChangeListener(mockPreferenceChangeListener);
        MockNodeChangeListener mockNodeChangeListener = new MockNodeChangeListener();
        p.addNodeChangeListener(mockNodeChangeListener);
        p.removeNodeChangeListener(mockNodeChangeListener);
        p.toString();
        p.sync();
        p.flush();
        try {
            p.exportNode(System.out);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            p.exportSubtree(System.out);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        p.isRemovedImpl();
        try {
            p.getChildImpl("");
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        p.cachedChildrenImpl();
    }

    public void testIllegalStateException() throws IOException,
            BackingStoreException {
        if (!(pref instanceof MockAbstractPreferences)) {
            return;
        }
        pref.removeNode();
        // after remove node, every methods, except name(), absolutePath(),
        // isUserNode(), flush() or nodeExists(""),
        // will throw illegal state exception
        pref.nodeExists("");
        pref.name();
        pref.absolutePath();
        pref.isUserNode();
        pref.toString();
        pref.flush();
        try {
            pref.nodeExists("child");
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.childrenNames();
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.remove(null);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.clear();
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.get("key", "null default");
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.put("nullkey", "value");
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.putInt("key", 3);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.getInt("key", 3);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.putLong("key", 3l);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.getLong("key", 3l);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.putDouble("key", 3);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.getDouble("key", 3);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.putBoolean("key", true);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.getBoolean("key", true);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.putFloat("key", 3f);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.getFloat("key", 3f);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.putByteArray("key", new byte[0]);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.getByteArray("key", new byte[0]);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.keys();
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.keys();
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.childrenNames();
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.parent();
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.node(null);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.removeNode();
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref
                    .addPreferenceChangeListener(new MockPreferenceChangeListener());
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref
                    .removePreferenceChangeListener(new MockPreferenceChangeListener());
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.addNodeChangeListener(new MockNodeChangeListener());
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.removeNodeChangeListener(new MockNodeChangeListener());
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.sync();
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.exportNode(null);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            pref.exportSubtree(null);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        if (!(pref instanceof MockAbstractPreferences)) {
            return;
        }
        MockAbstractPreferences p = (MockAbstractPreferences) pref;
        p.isRemovedImpl();
        p.cachedChildrenImpl();
        try {
            p.getChildImpl(null);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
    }

    public void testNullAndIllegalStateException() throws Exception {
        if (!(pref instanceof MockAbstractPreferences)) {
            return;
        }
        MockAbstractPreferences p = (MockAbstractPreferences) pref;
        p.removeNode();
        try {
            p.get(null, "null default");
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            p.put(null, "value");
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            p.putInt(null, 3);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            p.getInt(null, 3);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            p.putLong(null, 3l);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            p.getLong(null, 3l);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            p.putDouble(null, 3);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            p.getDouble(null, 3);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            p.putBoolean(null, true);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            p.getBoolean(null, true);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            p.putFloat(null, 3f);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            p.getFloat(null, 3f);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            p.putByteArray(null, new byte[0]);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            p.getByteArray(null, new byte[0]);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            p.addPreferenceChangeListener(null);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            p.removePreferenceChangeListener(null);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
        try {
            p.addNodeChangeListener(null);
            fail("should throw NullPointerException");
        } catch (NullPointerException expected) {
        }
        try {
            p.removeNodeChangeListener(null);
            fail("should throw IllegalStateException");
        } catch (IllegalStateException expected) {
        }
    }

    /**
     * Regression for HARMONY-828
     */
    public void testLongPath() throws Exception {
        assertFalse(pref.nodeExists("ddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd"));
    }

    public static class MockPreferenceChangeListener implements
            PreferenceChangeListener {
        private int changed = 0;

        public void preferenceChange(PreferenceChangeEvent pce) {
            changed++;
        }

        public int getChanged() {
            int result = changed;
            changed = 0;
            return result;
        }
    }

    public static class MockNodeChangeListener implements NodeChangeListener {
        private boolean addDispatched = false;

        private boolean removeDispatched = false;

        private Object addLock = new Object();

        private Object removeLock = new Object();

        private int added = 0;

        private int removed = 0;

        public void childAdded(NodeChangeEvent e) {
            synchronized (addLock) {
                ++added;
                addDispatched = true;
                addLock.notifyAll();
            }
        }

        public void childRemoved(NodeChangeEvent e) {
            synchronized (removeLock) {
                removed++;
                removeDispatched = true;
                removeLock.notifyAll();
            }
        }

        public int getAdded() {
            synchronized (addLock) {
                if (!addDispatched) {
                    try {
                        // TODO: don't know why must add limitation
                        addLock.wait(100);
                    } catch (InterruptedException e) {
                    }
                }
                addDispatched = false;
            }
            return added;
        }

        public int getRemoved() {
            synchronized (removeLock) {
                if (!removeDispatched) {
                    try {
                        removeLock.wait(100);
                    } catch (InterruptedException e) {
                    }
                }
                removeDispatched = false;
            }
            return removed;

        }

        public void reset() {
            added = 0;
            removed = 0;
        }
    }

}