1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.io.output; 18 19 import java.io.IOException; 20 import java.io.Writer; 21 22 /** 23 * Throws an IOException on all attempts to write with {@link #close()} implemented as a noop. 24 * <p> 25 * Typically uses of this class include testing for corner cases in methods that accept a writer and acting as a 26 * sentinel value instead of a {@code null} writer. 27 * </p> 28 * 29 * @since 2.7 30 */ 31 public class ClosedWriter extends Writer { 32 33 /** 34 * The singleton instance. 35 * 36 * @since 2.12.0 37 */ 38 public static final ClosedWriter INSTANCE = new ClosedWriter(); 39 40 /** 41 * The singleton instance. 42 * 43 * @deprecated Use {@link #INSTANCE}. 44 */ 45 @Deprecated 46 public static final ClosedWriter CLOSED_WRITER = INSTANCE; 47 48 @Override 49 public void close() throws IOException { 50 // noop 51 } 52 53 /** 54 * Throws an {@link IOException} to indicate that the stream is closed. 55 * 56 * @throws IOException always thrown 57 */ 58 @Override 59 public void flush() throws IOException { 60 throw new IOException("flush() failed: stream is closed"); 61 } 62 63 /** 64 * Throws an {@link IOException} to indicate that the writer is closed. 65 * 66 * @param cbuf ignored 67 * @param off ignored 68 * @param len ignored 69 * @throws IOException always thrown 70 */ 71 @Override 72 public void write(final char[] cbuf, final int off, final int len) throws IOException { 73 throw new IOException("write(" + new String(cbuf) + ", " + off + ", " + len + ") failed: stream is closed"); 74 } 75 }