org.apache.juneau.internal.TeeWriter Maven / Gradle / Ivy
// ***************************************************************************************************************************
// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file *
// * distributed with this work for additional information regarding copyright ownership. The ASF licenses this file *
// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance *
// * with the License. You may obtain a copy of the License at *
// * *
// * http://www.apache.org/licenses/LICENSE-2.0 *
// * *
// * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an *
// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the *
// * specific language governing permissions and limitations under the License. *
// ***************************************************************************************************************************
package org.apache.juneau.internal;
import java.io.*;
import java.util.*;
/**
* Writer that can send output to multiple writers.
*/
public class TeeWriter extends Writer {
private Writer[] writers = new Writer[0];
private Map writerMap;
/**
* Constructor.
*
* @param writers The list of writers.
*/
public TeeWriter(Writer...writers) {
this.writers = writers;
}
/**
* Constructor.
*
* @param writers The list of writers.
*/
public TeeWriter(Collection writers) {
this.writers = writers.toArray(new Writer[writers.size()]);
}
/**
* Adds a writer to this tee writer.
*
* @param w The writer to add to this tee writer.
* @param close
* If false , then calling {@link #close()} on this tee writer will not filter to the specified writer.
* @return This object (for method chaining).
*/
public TeeWriter add(Writer w, boolean close) {
if (w == null)
return this;
if (! close)
w = new NoCloseWriter(w);
if (w == this)
throw new RuntimeException("Cannot add this writer to itself.");
for (Writer w2 : writers)
if (w2 == w)
throw new RuntimeException("Cannot add this writer again.");
if (w instanceof TeeWriter) {
for (Writer w2 : ((TeeWriter)w).writers)
add(w2, true);
} else {
writers = ArrayUtils.append(writers, w);
}
return this;
}
/**
* Same as {@link #add(Writer, boolean)} but associates the writer with an identifier so the writer can be retrieved
* through {@link #getWriter(String)}.
*
* @param id The ID to associate the writer with.
* @param w The writer to add.
* @param close Close the specified writer afterwards.
* @return This object (for method chaining).
*/
public TeeWriter add(String id, Writer w, boolean close) {
if (id != null) {
if (writerMap == null)
writerMap = new TreeMap();
writerMap.put(id, w);
}
return add(w, close);
}
/**
* Returns the number of inner writers in this tee writer.
*
* @return The number of writers.
*/
public int size() {
return writers.length;
}
/**
* Returns the writer identified through the id parameter passed in through the
* {@link #add(String, Writer, boolean)} method.
*
* @param id The ID associated with the writer.
* @return The writer, or null if no identifier was specified when the writer was added.
*/
public Writer getWriter(String id) {
if (writerMap != null)
return writerMap.get(id);
return null;
}
@Override /* Writer */
public void write(char[] cbuf, int off, int len) throws IOException {
for (Writer w : writers)
if (w != null)
w.write(cbuf, off, len);
}
@Override /* Writer */
public void flush() throws IOException {
for (Writer w : writers)
if (w != null)
w.flush();
}
@Override /* Writer */
public void close() throws IOException {
IOException e = null;
for (Writer w : writers) {
if (w != null) {
try {
w.close();
} catch (IOException e2) {
e = e2;
}
}
}
if (e != null)
throw e;
}
private static class NoCloseWriter extends Writer {
private Writer writer;
private NoCloseWriter(Writer writer) {
this.writer = writer;
}
@Override /* Writer */
public void write(char[] cbuf, int off, int len) throws IOException {
writer.write(cbuf, off, len);
}
@Override /* Writer */
public void flush() throws IOException {
writer.flush();
}
@Override /* Writer */
public void close() throws IOException {
// Do nothing.
}
}
}