    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.Writer;
    020
    021/**
    022 * Never writes data. Calls never go beyond this class.
    023 * <p>
    024 * This {@link Writer} has no destination (file/socket etc.) and all characters written to it are ignored and lost.
    025 * </p>
    026 */
    027public class NullWriter extends Writer {
    028
    029    /**
    030     * The singleton instance.
    031     *
    032     * @since 2.12.0
    033     */
    034    public static final NullWriter INSTANCE = new NullWriter();
    035
    036    /**
    037     * The singleton instance.
    038     *
    039     * @deprecated Use {@link #INSTANCE}.
    040     */
    041    @Deprecated
    042    public static final NullWriter NULL_WRITER = INSTANCE;
    043
    044    /**
    045     * Constructs a new NullWriter.
    046     *
    047     * @deprecated Use {@link #INSTANCE}.
    048     */
    049    @Deprecated
    050    public NullWriter() {
    051    }
    052
    053    /**
    054     * Does nothing - output to {@code /dev/null}.
    055     * @param c The character to write
    056     * @return this writer
    057     * @since 2.0
    058     */
    059    @Override
    060    public Writer append(final char c) {
    061        //to /dev/null
    062        return this;
    063    }
    064
    065    /**
    066     * Does nothing - output to {@code /dev/null}.
    067     * @param csq The character sequence to write
    068     * @return this writer
    069     * @since 2.0
    070     */
    071    @Override
    072    public Writer append(final CharSequence csq) {
    073        //to /dev/null
    074        return this;
    075    }
    076
    077    /**
    078     * Does nothing - output to {@code /dev/null}.
    079     * @param csq The character sequence to write
    080     * @param start The index of the first character to write
    081     * @param end  The index of the first character to write (exclusive)
    082     * @return this writer
    083     * @since 2.0
    084     */
    085    @Override
    086    public Writer append(final CharSequence csq, final int start, final int end) {
    087        //to /dev/null
    088        return this;
    089    }
    090
    091    /** @see java.io.Writer#close() */
    092    @Override
    093    public void close() {
    094        //to /dev/null
    095    }
    096
    097    /** @see java.io.Writer#flush() */
    098    @Override
    099    public void flush() {
    100        //to /dev/null
    101    }
    102
    103    /**
    104     * Does nothing - output to {@code /dev/null}.
    105     * @param chr The characters to write
    106     */
    107    @Override
    108    public void write(final char[] chr) {
    109        //to /dev/null
    110    }
    111
    112    /**
    113     * Does nothing - output to {@code /dev/null}.
    114     * @param chr The characters to write
    115     * @param st The start offset
    116     * @param end The number of characters to write
    117     */
    118    @Override
    119    public void write(final char[] chr, final int st, final int end) {
    120        //to /dev/null
    121    }
    122
    123    /**
    124     * Does nothing - output to {@code /dev/null}.
    125     * @param idx The character to write
    126     */
    127    @Override
    128    public void write(final int idx) {
    129        //to /dev/null
    130    }
    131
    132    /**
    133     * Does nothing - output to {@code /dev/null}.
    134     * @param str The string to write
    135     */
    136    @Override
    137    public void write(final String str) {
    138        //to /dev/null
    139    }
    140
    141    /**
    142     * Does nothing - output to {@code /dev/null}.
    143     * @param str The string to write
    144     * @param st The start offset
    145     * @param end The number of characters to write
    146     */
    147    @Override
    148    public void write(final String str, final int st, final int end) {
    149        //to /dev/null
    150    }
    151
    152}