| 1 | /** |
| 2 | * Licensed to jclouds, Inc. (jclouds) under one or more |
| 3 | * contributor license agreements. See the NOTICE file |
| 4 | * distributed with this work for additional information |
| 5 | * regarding copyright ownership. jclouds licenses this file |
| 6 | * to you under the Apache License, Version 2.0 (the |
| 7 | * "License"); you may not use this file except in compliance |
| 8 | * with the License. You may obtain a copy of the License at |
| 9 | * |
| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 11 | * |
| 12 | * Unless required by applicable law or agreed to in writing, |
| 13 | * software distributed under the License is distributed on an |
| 14 | * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| 15 | * KIND, either express or implied. See the License for the |
| 16 | * specific language governing permissions and limitations |
| 17 | * under the License. |
| 18 | */ |
| 19 | package org.jclouds.util; |
| 20 | |
| 21 | import java.io.IOException; |
| 22 | import java.io.InputStream; |
| 23 | import java.util.LinkedList; |
| 24 | |
| 25 | /** |
| 26 | * {@link InputStream} implementation that allows chaining of various streams for seamless |
| 27 | * sequential reading |
| 28 | * |
| 29 | * @author Adrian Cole |
| 30 | * @author Tomas Varaneckas <tomas.varaneckas@gmail.com> |
| 31 | */ |
| 32 | public class InputStreamChain extends InputStream { |
| 33 | |
| 34 | /** |
| 35 | * Input stream chain |
| 36 | */ |
| 37 | private final LinkedList<InputStream> streams = new LinkedList<InputStream>(); |
| 38 | |
| 39 | /** |
| 40 | * Currently active stream |
| 41 | */ |
| 42 | private InputStream current; |
| 43 | |
| 44 | public InputStreamChain(InputStream... inputStreams) { |
| 45 | for (InputStream stream : inputStreams) { |
| 46 | addInputStream(stream); |
| 47 | } |
| 48 | } |
| 49 | |
| 50 | /** |
| 51 | * Adds input stream to the end of chain |
| 52 | * |
| 53 | * @param stream |
| 54 | * InputStream to add to chain |
| 55 | * @return instance of self (for fluent calls) |
| 56 | */ |
| 57 | public InputStreamChain addInputStream(final InputStream stream) { |
| 58 | streams.addLast(stream); |
| 59 | if (current == null) { |
| 60 | current = streams.removeFirst(); |
| 61 | } |
| 62 | return this; |
| 63 | } |
| 64 | |
| 65 | /** |
| 66 | * Adds a String to the end of chain |
| 67 | * |
| 68 | * @param value |
| 69 | * String to add to the chain |
| 70 | * @return instance of self (for fluent calls) |
| 71 | */ |
| 72 | public InputStreamChain addAsInputStream(final String value) { |
| 73 | return addInputStream(Strings2.toInputStream(value)); |
| 74 | } |
| 75 | |
| 76 | @Override |
| 77 | public int read() throws IOException { |
| 78 | int bit = current.read(); |
| 79 | if (bit == -1 && streams.size() > 0) { |
| 80 | try { |
| 81 | current.close(); |
| 82 | } catch (final IOException e) { |
| 83 | // replace this with a call to logging facility |
| 84 | e.printStackTrace(); |
| 85 | } |
| 86 | current = streams.removeFirst(); |
| 87 | bit = read(); |
| 88 | } |
| 89 | return bit; |
| 90 | } |
| 91 | |
| 92 | @Override |
| 93 | public int available() throws IOException { |
| 94 | int available = current.available(); |
| 95 | for (InputStream stream : streams) { |
| 96 | available += stream.available(); |
| 97 | } |
| 98 | return available; |
| 99 | } |
| 100 | |
| 101 | @Override |
| 102 | public void close() throws IOException { |
| 103 | current.close(); |
| 104 | } |
| 105 | |
| 106 | @Override |
| 107 | public boolean markSupported() { |
| 108 | return current.markSupported(); |
| 109 | } |
| 110 | |
| 111 | @Override |
| 112 | public synchronized void mark(int i) { |
| 113 | current.mark(i); |
| 114 | } |
| 115 | |
| 116 | @Override |
| 117 | public synchronized void reset() throws IOException { |
| 118 | current.reset(); |
| 119 | } |
| 120 | |
| 121 | @Override |
| 122 | public long skip(long l) throws IOException { |
| 123 | return current.skip(l); |
| 124 | } |
| 125 | |
| 126 | } |