org.apache.tools.ant.util.KeepAliveOutputStream 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
*
* https://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.tools.ant.util;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
/**
* Class that can be used to wrap System.out and System.err
* without getting anxious about any client closing the stream.
*
*
* In code-language it means that it is not necessary to do:
*
* if (out != System.out && out != System.err) {
* out.close();
* }
*
*
*/
public class KeepAliveOutputStream extends FilterOutputStream {
/**
* Constructor of KeepAliveOutputStream.
*
* @param out an OutputStream value, it should be standard output.
*/
public KeepAliveOutputStream(OutputStream out) {
super(out);
}
/**
* This method does nothing.
* @throws IOException as we are overriding FilterOutputStream.
*/
public void close() throws IOException {
// do not close the stream
}
/**
* Convenience factory method that returns a non-closing
* PrintStream around System.out.
*
* @return PrintStream
* @since Ant 1.8.0
*/
public static PrintStream wrapSystemOut() {
return wrap(System.out);
}
/**
* Convenience factory method that returns a non-closing
* PrintStream around System.err.
*
* @return PrintStream
* @since Ant 1.8.0
*/
public static PrintStream wrapSystemErr() {
return wrap(System.err);
}
/**
* @return PrintStream
* @since Ant 1.8.0
*/
private static PrintStream wrap(PrintStream ps) {
return new PrintStream(new KeepAliveOutputStream(ps));
}
}