ByteArrayOutputStream.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.io.output;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * Implements a ThreadSafe version of {@link AbstractByteArrayOutputStream} using instance synchronization.
 */
//@ThreadSafe
public class ByteArrayOutputStream extends AbstractByteArrayOutputStream<ByteArrayOutputStream> {

    /**
     * Fetches entire contents of an {@link InputStream} and represent
     * same data as result InputStream.
     * <p>
     * This method is useful where,
     * </p>
     * <ul>
     * <li>Source InputStream is slow.</li>
     * <li>It has network resources associated, so we cannot keep it open for
     * long time.</li>
     * <li>It has network timeout associated.</li>
     * </ul>
     * It can be used in favor of {@link #toByteArray()}, since it
     * avoids unnecessary allocation and copy of byte[].<br>
     * This method buffers the input internally, so there is no need to use a
     * {@link BufferedInputStream}.
     *
     * @param input Stream to be fully buffered.
     * @return A fully buffered stream.
     * @throws IOException if an I/O error occurs.
     * @since 2.0
     */
    public static InputStream toBufferedInputStream(final InputStream input)
            throws IOException {
        return toBufferedInputStream(input, DEFAULT_SIZE);
    }

    /**
     * Fetches entire contents of an {@link InputStream} and represent
     * same data as result InputStream.
     * <p>
     * This method is useful where,
     * </p>
     * <ul>
     * <li>Source InputStream is slow.</li>
     * <li>It has network resources associated, so we cannot keep it open for
     * long time.</li>
     * <li>It has network timeout associated.</li>
     * </ul>
     * It can be used in favor of {@link #toByteArray()}, since it
     * avoids unnecessary allocation and copy of byte[].<br>
     * This method buffers the input internally, so there is no need to use a
     * {@link BufferedInputStream}.
     *
     * @param input Stream to be fully buffered.
     * @param size the initial buffer size
     * @return A fully buffered stream.
     * @throws IOException if an I/O error occurs.
     * @since 2.5
     */
    public static InputStream toBufferedInputStream(final InputStream input, final int size)
        throws IOException {
        try (ByteArrayOutputStream output = new ByteArrayOutputStream(size)) {
            output.write(input);
            return output.toInputStream();
        }
    }

    /**
     * Constructs a new byte array output stream. The buffer capacity is
     * initially {@value AbstractByteArrayOutputStream#DEFAULT_SIZE} bytes, though its size increases if necessary.
     */
    public ByteArrayOutputStream() {
        this(DEFAULT_SIZE);
    }

    /**
     * Constructs a new byte array output stream, with a buffer capacity of
     * the specified size, in bytes.
     *
     * @param size  the initial size
     * @throws IllegalArgumentException if size is negative
     */
    public ByteArrayOutputStream(final int size) {
        if (size < 0) {
            throw new IllegalArgumentException("Negative initial size: " + size);
        }
        synchronized (this) {
            needNewBuffer(size);
        }
    }

    /**
     * @see java.io.ByteArrayOutputStream#reset()
     */
    @Override
    public synchronized void reset() {
        resetImpl();
    }

    @Override
    public synchronized int size() {
        return count;
    }

    @Override
    public synchronized byte[] toByteArray() {
        return toByteArrayImpl();
    }

    @Override
    public synchronized InputStream toInputStream() {
        return toInputStream(java.io.ByteArrayInputStream::new);
    }

    @Override
    public void write(final byte[] b, final int off, final int len) {
        if (off < 0
                || off > b.length
                || len < 0
                || off + len > b.length
                || off + len < 0) {
            throw new IndexOutOfBoundsException();
        }
        if (len == 0) {
            return;
        }
        synchronized (this) {
            writeImpl(b, off, len);
        }
    }

    @Override
    public synchronized int write(final InputStream in) throws IOException {
        return writeImpl(in);
    }

    @Override
    public synchronized void write(final int b) {
        writeImpl(b);
    }

    @Override
    public synchronized void writeTo(final OutputStream out) throws IOException {
        writeToImpl(out);
    }
}