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 *      https://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.IOException;
020import java.io.OutputStream;
021
022import org.apache.commons.io.IOUtils;
023
024/**
025 * Never writes data. Calls never go beyond this class.
026 * <p>
027 * This output stream has no destination and all bytes written to it are ignored.
028 * </p>
029 */
030public class NullOutputStream extends OutputStream {
031
032    /**
033     * The singleton instance.
034     *
035     * @since 2.12.0
036     */
037    public static final NullOutputStream INSTANCE = new NullOutputStream();
038
039    /**
040     * The singleton instance.
041     *
042     * @deprecated Use {@link #INSTANCE}.
043     */
044    @Deprecated
045    public static final NullOutputStream NULL_OUTPUT_STREAM = INSTANCE;
046
047    /**
048     * Deprecated in favor of {@link #INSTANCE}.
049     * <p>
050     * TODO: Will be private in 3.0.
051     * </p>
052     *
053     * @deprecated Use {@link #INSTANCE}.
054     */
055    @Deprecated
056    public NullOutputStream() {
057        // empty
058    }
059
060    /**
061     * Does nothing.
062     *
063     * @param b The This method ignores this parameter.
064     * @throws IOException This method never throws any exceptions.
065     */
066    @Override
067    public void write(final byte[] b) throws IOException {
068        // noop
069    }
070
071    /**
072     * No-op operation.
073     *
074     * <p>Validates the arguments but does not write the data.</p>
075     *
076     * @param b   The byte array to write from, not {@code null}.
077     * @param off The offset to start at.
078     * @param len The number of bytes to write.
079     * @throws NullPointerException      If {@code b} is {@code null}.
080     * @throws IndexOutOfBoundsException If {@code off} or {@code len} are negative, {@code off + len} is greater than
081     *                                   {@code b.length}.
082     */
083    @Override
084    public void write(final byte[] b, final int off, final int len) {
085        IOUtils.checkFromIndexSize(b, off, len);
086    }
087
088    /**
089     * Does nothing.
090     *
091     * @param b This method ignores this parameter.
092     */
093    @Override
094    public void write(final int b) {
095        // noop
096    }
097
098}