AppendableWriterTest.java revision 1d580d0f6ee4f21eb309ba7b509d2c6d671c4044 
1/*
2 * Copyright (C) 2007 The Guava Authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.google.common.io;
18
19import java.io.Closeable;
20import java.io.Flushable;
21import java.io.IOException;
22import java.io.Writer;
23
24/**
25 * Unit test for {@link AppendableWriter}.
26 *
27 * @author Alan Green
28 */
29public class AppendableWriterTest extends IoTestCase {
30
31  /** Helper class for testing behavior with Flushable and Closeable targets. */
32  private static class SpyAppendable implements Appendable, Flushable, Closeable {
33    boolean flushed;
34    boolean closed;
35    StringBuilder result = new StringBuilder();
36
37    @Override public Appendable append(CharSequence csq) {
38      result.append(csq);
39      return this;
40    }
41
42    @Override public Appendable append(char c) {
43      result.append(c);
44      return this;
45    }
46
47    @Override public Appendable append(CharSequence csq, int start, int end) {
48      result.append(csq, start, end);
49      return this;
50    }
51
52    @Override public void flush() {
53      flushed = true;
54    }
55
56    @Override public void close() {
57      closed = true;
58    }
59  }
60
61  public void testWriteMethods() throws IOException {
62    StringBuilder builder = new StringBuilder();
63    Writer writer = new AppendableWriter(builder);
64
65    writer.write("Hello".toCharArray());
66    writer.write(',');
67    writer.write(0xBEEF0020); // only lower 16 bits are important
68    writer.write("Wo");
69    writer.write("Whirled".toCharArray(), 3, 2);
70    writer.write("Mad! Mad, I say", 2, 2);
71
72    assertEquals("Hello, World!", builder.toString());
73  }
74
75  public void testAppendMethods() throws IOException {
76    StringBuilder builder = new StringBuilder();
77    Writer writer = new AppendableWriter(builder);
78
79    writer.append("Hello,");
80    writer.append(' ');
81    writer.append("The World Wide Web", 4, 9);
82    writer.append("!");
83
84    assertEquals("Hello, World!", builder.toString());
85  }
86
87  public void testCloseFlush() throws IOException {
88    SpyAppendable spy = new SpyAppendable();
89    Writer writer = new AppendableWriter(spy);
90
91    writer.write("Hello");
92    assertFalse(spy.flushed);
93    assertFalse(spy.closed);
94
95    writer.flush();
96    assertTrue(spy.flushed);
97    assertFalse(spy.closed);
98
99    writer.close();
100    assertTrue(spy.flushed);
101    assertTrue(spy.closed);
102  }
103
104  public void testCloseIsFinal() throws IOException {
105    StringBuilder builder = new StringBuilder();
106    Writer writer = new AppendableWriter(builder);
107
108    writer.write("Hi");
109    writer.close();
110
111    try {
112      writer.write(" Greg");
113      fail("Should have thrown IOException due to writer already closed");
114    } catch (IOException es) {
115      // expected
116    }
117
118    try {
119      writer.flush();
120      fail("Should have thrown IOException due to writer already closed");
121    } catch (IOException es) {
122      // expected
123    }
124
125    // close()ing already closed writer is allowed
126    writer.close();
127  }
128}
129