gogo/src/aQute/threadio/ThreadIOImpl.java

/*
 * 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.
 */
// DWB20: ThreadIO should check and reset IO if something (e.g. jetty) overrides
package aQute.threadio;

import java.io.*;
import java.util.logging.Logger;

import org.osgi.service.component.*;
import org.osgi.service.threadio.*;

public class ThreadIOImpl implements ThreadIO {
    static private final Logger log = Logger.getLogger(ThreadIOImpl.class.getName());
	ThreadPrintStream err = new ThreadPrintStream(System.err);
	ThreadPrintStream out = new ThreadPrintStream(System.out);
	ThreadInputStream in = new ThreadInputStream(System.in);
    ThreadLocal<Marker> current = new ThreadLocal<Marker>();
	
	protected void activate(ComponentContext context) {
		start();
	}

	protected void deactivate() {
	    stop();
	}
	
	public void stop() {
		System.setErr(err.dflt);
		System.setOut(out.dflt);
		System.setIn(in.dflt);
	}

	public void start() {
		if ( System.out instanceof ThreadPrintStream )
			throw new IllegalStateException("Thread Print Stream already set");
		System.setOut(out);
		System.setIn(in);
        System.setErr(err);
	}
	
	private void checkIO() {    // derek
	    if (System.in != in) {
	        log.fine("ThreadIO: eek! who's set System.in=" + System.in);
		System.setIn(in);
	    }
	    
	    if (System.out != out) {
	        log.fine("ThreadIO: eek! who's set System.out=" + System.out);
		System.setOut(out);
	    }
	    
	    if (System.err != err) {
	        log.fine("ThreadIO: eek! who's set System.err=" + System.err);
		System.setErr(err);
	    }
	}
	
	public void close() {
	    checkIO(); // derek
	    Marker top = this.current.get();
	    if ( top == null )
	        throw new IllegalStateException("No thread io active");

	    Marker previous = top.previous;
	    if (previous==null) {
	        in.end();
	        out.end();
	        err.end();
	    } else {
            this.current.set(previous);
    	    previous.activate();
	    }
	}

	public void setStreams(InputStream in, PrintStream out, PrintStream err) {
        assert in != null;
        assert out != null;
        assert err != null;
        checkIO(); // derek
        Marker marker = new Marker(this,in,out,err, current.get());
	    this.current.set(marker);
	    marker.activate();
	}
}