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      1 /*
      2  * Copyright (C) 2008 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 
     17 package com.google.common.io;
     18 
     19 import com.google.common.collect.ImmutableList;
     20 
     21 import junit.framework.TestCase;
     22 
     23 import java.io.FilterReader;
     24 import java.io.IOException;
     25 import java.io.Reader;
     26 import java.io.StringReader;
     27 
     28 /**
     29  * @author ricebin
     30  */
     31 public class MultiReaderTest extends TestCase {
     32 
     33   public void testOnlyOneOpen() throws Exception {
     34     String testString = "abcdefgh";
     35     final CharSource source = newCharSource(testString);
     36     final int[] counter = new int[1];
     37     CharSource reader = new CharSource() {
     38       @Override
     39       public Reader openStream() throws IOException {
     40         if (counter[0]++ != 0) {
     41           throw new IllegalStateException("More than one source open");
     42         }
     43         return new FilterReader(source.openStream()) {
     44           @Override public void close() throws IOException {
     45             super.close();
     46             counter[0]--;
     47           }
     48         };
     49       }
     50     };
     51     Reader joinedReader = CharSource.concat(reader, reader, reader).openStream();
     52     String result = CharStreams.toString(joinedReader);
     53     assertEquals(testString.length() * 3, result.length());
     54   }
     55 
     56   public void testReady() throws Exception {
     57     CharSource source = newCharSource("a");
     58     Iterable<? extends CharSource> list = ImmutableList.of(source, source);
     59     Reader joinedReader = CharSource.concat(list).openStream();
     60 
     61     assertTrue(joinedReader.ready());
     62     assertEquals('a', joinedReader.read());
     63     assertEquals('a', joinedReader.read());
     64     assertEquals(-1, joinedReader.read());
     65     assertFalse(joinedReader.ready());
     66   }
     67 
     68   public void testSimple() throws Exception {
     69     String testString = "abcdefgh";
     70     CharSource source = newCharSource(testString);
     71     Reader joinedReader = CharSource.concat(source, source).openStream();
     72 
     73     String expectedString = testString + testString;
     74     assertEquals(expectedString, CharStreams.toString(joinedReader));
     75   }
     76 
     77 
     78   private static CharSource newCharSource(final String text) {
     79     return new CharSource() {
     80       @Override
     81       public Reader openStream() {
     82         return new StringReader(text);
     83       }
     84     };
     85   }
     86 
     87   public void testSkip() throws Exception {
     88     String begin = "abcde";
     89     String end = "fghij";
     90     Reader joinedReader =
     91         CharSource.concat(newCharSource(begin), newCharSource(end)).openStream();
     92 
     93     String expected = begin + end;
     94     assertEquals(expected.charAt(0), joinedReader.read());
     95     CharStreams.skipFully(joinedReader, 1);
     96     assertEquals(expected.charAt(2), joinedReader.read());
     97     CharStreams.skipFully(joinedReader, 4);
     98     assertEquals(expected.charAt(7), joinedReader.read());
     99     CharStreams.skipFully(joinedReader, 1);
    100     assertEquals(expected.charAt(9), joinedReader.read());
    101     assertEquals(-1, joinedReader.read());
    102   }
    103 
    104   public void testSkipZero() throws Exception {
    105     CharSource source = newCharSource("a");
    106     Iterable<CharSource> list = ImmutableList.of(source, source);
    107     Reader joinedReader = CharSource.concat(list).openStream();
    108 
    109     assertEquals(0, joinedReader.skip(0));
    110     assertEquals('a', joinedReader.read());
    111   }
    112 
    113 }
    114