Copyright (c) 2006, 2016 Cognos Incorporated, IBM Corporation and others
This program and the accompanying materials are made
available under the terms of the Eclipse Public License 2.0 which
accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
/*******************************************************************************
 * Copyright (c) 2006, 2016 Cognos Incorporated, IBM Corporation and others
 *
 * This program and the accompanying materials are made
 * available under the terms of the Eclipse Public License 2.0 which
 * accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 ******************************************************************************/
package org.eclipse.osgi.internal.log;

import java.util.*;
import org.eclipse.equinox.log.ExtendedLogReaderService;
import org.eclipse.equinox.log.LogFilter;
import org.osgi.service.log.LogEntry;
import org.osgi.service.log.LogListener;

public class ExtendedLogReaderServiceImpl implements ExtendedLogReaderService {

	private final ExtendedLogReaderServiceFactory factory;
	private Set<LogListener> listeners = new HashSet<>();

	ExtendedLogReaderServiceImpl(ExtendedLogReaderServiceFactory factory) {
		this.factory = factory;
	}

	@Override
	public synchronized void addLogListener(LogListener listener, LogFilter filter) {
		checkShutdown();
		if (listener == null)
			throw new IllegalArgumentException("LogListener must not be null"); //$NON-NLS-1$

		if (filter == null)
			throw new IllegalArgumentException("LogFilter must not be null"); //$NON-NLS-1$		

		listeners.add(listener);
		factory.addLogListener(listener, filter);
	}

	@Override
	public void addLogListener(LogListener listener) {
		addLogListener(listener, ExtendedLogReaderServiceFactory.NULL_LOGGER_FILTER);
	}

	@Override
	public Enumeration<LogEntry> getLog() {
		checkShutdown();
		return factory.getLog();
	}

	@Override
	public synchronized void removeLogListener(LogListener listener) {
		checkShutdown();
		if (listener == null)
			throw new IllegalArgumentException("LogListener must not be null"); //$NON-NLS-1$

		factory.removeLogListener(listener);
		listeners.remove(listener);
	}

	private synchronized void checkShutdown() {
		if (listeners == null)
			throw new IllegalStateException("LogReaderService is shutdown."); //$NON-NLS-1$
	}

	synchronized void shutdown() {
		for (LogListener listener : listeners) {
			factory.removeLogListener(listener);
		}
		listeners = null;
	}
}