    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 */
    017
    018package org.apache.commons.io.output;
    019
    020import java.io.Writer;
    021
    022/**
    023 * Proxy writer that prevents the underlying writer from being closed.
    024 * <p>
    025 * This class is typically used in cases where a writer needs to be passed to a 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     * Constructs 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     * Constructs 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 underlying writer is never closed. Use {@link #wrap(Writer)} instead.
    049     */
    050    @Deprecated
    051    public CloseShieldWriter(final Writer writer) {
    052        super(writer);
    053    }
    054
    055    /**
    056     * Replaces the underlying writer with a {@link ClosedWriter} sentinel. The original writer will remain open, but this proxy will appear closed.
    057     */
    058    @Override
    059    public void close() {
    060        out = ClosedWriter.INSTANCE;
    061    }
    062}