ScannerParseLargeFileBenchmarkTest.java revision 561ee011997c6c2f1befbfaa9d5f0a99771c1d63 
1/* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements.  See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License.  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 */
16package org.apache.harmony.luni.tests.java.util;
17
18import java.io.IOException;
19import java.io.Reader;
20import java.util.Scanner;
21
22import org.junit.Test;
23
24public class ScannerParseLargeFileBenchmarkTest {
25
26    /**
27     * This test will check when parse a large file like more than 200M bytes if
28     * the Scanner will exhaust all heap memory
29     */
30    @Test
31    public void testParseLargeFile() throws Exception {
32        MyReader reader = new MyReader();
33        String delimiter = "\r?\n";
34        Scanner scanner = new Scanner(reader).useDelimiter(delimiter);
35
36        while (scanner.hasNext()) {
37            scanner.next();
38        }
39        scanner.close();
40        reader.close();
41    }
42
43    private static class MyReader extends Reader {
44        static final char[] CONTENT = "large file!\n".toCharArray();
45
46        static long fileLength = (8 << 21) * 12;
47
48        static boolean first = true;
49
50        static int position = 0;
51
52        private int count = 0;
53
54        @Override
55        public void close() throws IOException {
56        }
57
58        @Override
59        public int read(char[] buf, int offset, int length) {
60            if (count >= fileLength) {
61                return -1;
62            }
63            if (first == true) {
64                position = 0;
65                first = false;
66            }
67            for (int i = offset; i < length; i++) {
68                buf[i] = CONTENT[(i + position) % CONTENT.length];
69                count++;
70            }
71
72            position = (length + position) % CONTENT.length;
73
74            return length - offset;
75        }
76    }
77}
78