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 * Proxy writer that prevents the underlying writer from being closed.
023 * <p>
024 * This class is typically used in cases where a writer needs to be passed to a
025 * component that wants to explicitly close the writer even if other components
026 * would still use the writer for output.
027 * </p>
028 *
029 * @since 2.7
030 */
031public class CloseShieldWriter extends ProxyWriter {
032
033    /**
034     * Creates a proxy that shields the given writer from being closed.
035     *
036     * @param writer the writer to wrap
037     * @return the created proxy
038     * @since 2.9.0
039     */
040    public static CloseShieldWriter wrap(final Writer writer) {
041        return new CloseShieldWriter(writer);
042    }
043
044    /**
045     * Creates a proxy that shields the given writer from being closed.
046     *
047     * @param writer underlying writer
048     * @deprecated Using this constructor prevents IDEs from warning if the
049     *             underlying writer is never closed. Use {@link #wrap(Writer)}
050     *             instead.
051     */
052    @Deprecated
053    public CloseShieldWriter(final Writer writer) {
054        super(writer);
055    }
056
057    /**
058     * Replaces the underlying writer with a {@link ClosedWriter} sentinel. The
059     * original writer will remain open, but this proxy will appear closed.
060     */
061    @Override
062    public void close() {
063        out = ClosedWriter.CLOSED_WRITER;
064    }
065
066}