001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.io.output;
018
019import java.io.FilterOutputStream;
020import java.io.IOException;
021import java.io.OutputStream;
022
023import org.apache.commons.io.IOUtils;
024import org.apache.commons.io.build.AbstractStreamBuilder;
025
026/**
027 * OutputStream which breaks larger output blocks into chunks. Native code may need to copy the input array; if the write buffer is very large this can cause
028 * OOME.
029 *
030 * @since 2.5
031 */
032public class ChunkedOutputStream extends FilterOutputStream {
033
034    // @formatter:off
035    /**
036     * Builds a new {@link UnsynchronizedByteArrayOutputStream} instance.
037     * <p>
038     * Using File IO:
039     * </p>
040     *
041     * <pre>{@code
042     * UnsynchronizedByteArrayOutputStream s = UnsynchronizedByteArrayOutputStream.builder()
043     *   .setBufferSize(8192)
044     *   .get();
045     * }
046     * </pre>
047     * <p>
048     * Using NIO Path:
049     * </p>
050     *
051     * <pre>{@code
052     * UnsynchronizedByteArrayOutputStream s = UnsynchronizedByteArrayOutputStream.builder()
053     *   .setBufferSize(8192)
054     *   .get();
055     * }
056     * </pre>
057     *
058     * @since 2.13.0
059     */
060    // @formatter:on
061    public static class Builder extends AbstractStreamBuilder<ChunkedOutputStream, Builder> {
062
063        /**
064         * Constructs a new instance.
065         * <p>
066         * This builder use the aspects OutputStream and buffer size (chunk size).
067         * </p>
068         *
069         * @return a new instance.
070         * @throws IOException                   if an I/O error occurs.
071         * @throws UnsupportedOperationException if the origin cannot be converted to an OutputStream.
072         * @see #getOutputStream()
073         */
074        @Override
075        public ChunkedOutputStream get() throws IOException {
076            return new ChunkedOutputStream(getOutputStream(), getBufferSize());
077        }
078
079    }
080
081    /**
082     * Constructs a new {@link Builder}.
083     *
084     * @return a new {@link Builder}.
085     * @since 2.13.0
086     */
087    public static Builder builder() {
088        return new Builder();
089    }
090
091    /**
092     * The maximum chunk size to us when writing data arrays
093     */
094    private final int chunkSize;
095
096    /**
097     * Constructs a new stream that uses a chunk size of {@link IOUtils#DEFAULT_BUFFER_SIZE}.
098     *
099     * @param stream the stream to wrap
100     * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
101     */
102    @Deprecated
103    public ChunkedOutputStream(final OutputStream stream) {
104        this(stream, IOUtils.DEFAULT_BUFFER_SIZE);
105    }
106
107    /**
108     * Constructs a new stream that uses the specified chunk size.
109     *
110     * @param stream    the stream to wrap
111     * @param chunkSize the chunk size to use; must be a positive number.
112     * @throws IllegalArgumentException if the chunk size is &lt;= 0
113     * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
114     */
115    @Deprecated
116    public ChunkedOutputStream(final OutputStream stream, final int chunkSize) {
117        super(stream);
118        if (chunkSize <= 0) {
119            throw new IllegalArgumentException("chunkSize <= 0");
120        }
121        this.chunkSize = chunkSize;
122    }
123
124    int getChunkSize() {
125        return chunkSize;
126    }
127
128    /**
129     * Writes the data buffer in chunks to the underlying stream
130     *
131     * @param data      the data to write
132     * @param srcOffset the offset
133     * @param length    the length of data to write
134     *
135     * @throws IOException if an I/O error occurs.
136     */
137    @Override
138    public void write(final byte[] data, final int srcOffset, final int length) throws IOException {
139        int bytes = length;
140        int dstOffset = srcOffset;
141        while (bytes > 0) {
142            final int chunk = Math.min(bytes, chunkSize);
143            out.write(data, dstOffset, chunk);
144            bytes -= chunk;
145            dstOffset += chunk;
146        }
147    }
148
149}