ConsoleRedirector.java

package aQute.remote.agent;

import java.io.IOException;
import java.io.PrintStream;
import java.util.concurrent.CopyOnWriteArrayList;

import aQute.remote.api.Agent;

/**
 * The Console Redirector redirects System.in, System.out, and System.err to the
 * supervisor. This is of course quite tricky. We have to replace System.*
 * fields and this can only be done if the security allows it. It also requires
 * that if we have multiple agents we need to share the redirecting.
 */
public class ConsoleRedirector implements Redirector {
	private static RedirectOutput						stdout;
	private static RedirectOutput						stderr;
	private static RedirectInput						stdin;
	private static CopyOnWriteArrayList<AgentServer>	agents	= new CopyOnWriteArrayList<AgentServer>();
	volatile boolean									quit	= false;

	/**
	 * Constructor.
	 * 
	 * @param agent the agent we're redirecting for
	 */
	public ConsoleRedirector(AgentServer agent) throws IOException {
		synchronized (agents) {
			if (!agents.contains(this)) {
				agents.add(agent);
				if (agents.size() == 1) {
					System.setOut(stdout = new RedirectOutput(agents, System.out, false));
					System.setErr(stderr = new RedirectOutput(agents, System.err, true));
					System.setIn(stdin = new RedirectInput(System.in));
				}
			}
		}
	}

	/**
	 * Clean up
	 */
	@Override
	public void close() throws IOException {
		quit = true;
		synchronized (agents) {
			if (agents.remove(this)) {
				if (agents.size() == 0) {
					System.setOut(stdout.getOut());
					System.setErr(stderr.getOut());
					System.setIn(stdin.getOrg());
				}
			}
		}
	}

	@Override
	public int getPort() {
		return Agent.CONSOLE;
	}

	@Override
	public void stdin(String s) throws IOException {
		stdin.add(s);
	}

	@Override
	public PrintStream getOut() {
		return stdout;
	}

}