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/*
 * 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.input;

import static org.apache.commons.io.IOUtils.EOF;

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

/**
 * InputStream proxy that transparently writes a copy of all bytes read
 * from the proxied stream to a given OutputStream. Using {@link #skip(long)}
 * or {@link #mark(int)}/{@link #reset()} on the stream will result on some
 * bytes from the input stream being skipped or duplicated in the output
 * stream.
 * 

* The proxied input stream is closed when the {@link #close()} method is * called on this proxy. It is configurable whether the associated output * stream will also closed. * * @since 1.4 * @see ObservableInputStream */ public class TeeInputStream extends ProxyInputStream { /** * The output stream that will receive a copy of all bytes read from the * proxied input stream. */ private final OutputStream branch; /** * Flag for closing also the associated output stream when this * stream is closed. */ private final boolean closeBranch; /** * Creates a TeeInputStream that proxies the given {@link InputStream} * and copies all read bytes to the given {@link OutputStream}. The given * output stream will not be closed when this stream gets closed. * * @param input input stream to be proxied * @param branch output stream that will receive a copy of all bytes read */ public TeeInputStream(final InputStream input, final OutputStream branch) { this(input, branch, false); } /** * Creates a TeeInputStream that proxies the given {@link InputStream} * and copies all read bytes to the given {@link OutputStream}. The given * output stream will be closed when this stream gets closed if the * closeBranch parameter is {@code true}. * * @param input input stream to be proxied * @param branch output stream that will receive a copy of all bytes read * @param closeBranch flag for closing also the output stream when this * stream is closed */ public TeeInputStream( final InputStream input, final OutputStream branch, final boolean closeBranch) { super(input); this.branch = branch; this.closeBranch = closeBranch; } /** * Closes the proxied input stream and, if so configured, the associated * output stream. An exception thrown from one stream will not prevent * closing of the other stream. * * @throws IOException if either of the streams could not be closed */ @Override public void close() throws IOException { try { super.close(); } finally { if (closeBranch) { branch.close(); } } } /** * Reads a single byte from the proxied input stream and writes it to * the associated output stream. * * @return next byte from the stream, or -1 if the stream has ended * @throws IOException if the stream could not be read (or written) */ @Override public int read() throws IOException { final int ch = super.read(); if (ch != EOF) { branch.write(ch); } return ch; } /** * Reads bytes from the proxied input stream and writes the read bytes * to the associated output stream. * * @param bts byte buffer * @param st start offset within the buffer * @param end maximum number of bytes to read * @return number of bytes read, or -1 if the stream has ended * @throws IOException if the stream could not be read (or written) */ @Override public int read(final byte[] bts, final int st, final int end) throws IOException { final int n = super.read(bts, st, end); if (n != -1) { branch.write(bts, st, n); } return n; } /** * Reads bytes from the proxied input stream and writes the read bytes * to the associated output stream. * * @param bts byte buffer * @return number of bytes read, or -1 if the stream has ended * @throws IOException if the stream could not be read (or written) */ @Override public int read(final byte[] bts) throws IOException { final int n = super.read(bts); if (n != EOF) { branch.write(bts, 0, n); } return n; } }





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