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Guise™ Internet application framework.

There is a newer version: 0.5.3

/*
 * Copyright © 2005-2008 GlobalMentor, Inc. 
 *
 * Licensed 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 io.guise.framework;

import static java.util.Objects.*;

import java.util.Optional;

import io.csar.*;

/**
 * A thread group allocated to a Guise session. All threads accessing a Guise session should be part of the session's thread group.
 * 
 * This thread group also allows access to managed configurations using {@link Concern}. Thread-group-local configurations are retrieved by searching for a
 * configuration first in the Guise session using {@link GuiseSession#findConcern(Class)}, and second in the Guise application using
 * {@link GuiseApplication#findConcern(Class)}.
 * 
 * @author Garret Wilson
 */
public class GuiseSessionThreadGroup extends ThreadGroup implements Concerned {

	/** The Guise session to which this thread group belongs and in which its related threads run. */
	private final GuiseSession guiseSession;

	/** @return The Guise session to which this thread group belongs and in which its related threads run. */
	public GuiseSession getGuiseSession() {
		return guiseSession;
	}

	/**
	 * Guise session constructor.
	 * @param guiseSession The Guise session to which this thread group belongs and in which its related threads run.
	 * @throws NullPointerException if the given Guise session is null.
	 */
	public GuiseSessionThreadGroup(final GuiseSession guiseSession) {
		super("Guise Session Thread Group " + guiseSession.toString()); //construct the parent class TODO improve name
		this.guiseSession = requireNonNull(guiseSession, "Guise session cannot be null.");
	}

	@Override
	public  Optional findConcern(final Class configurationClass) {
		return guiseSession.findConcern(configurationClass) //see if the session has the requested configuration
				//if no such configuration was found in the session, see if the application has the requested configuration
				.or(() -> guiseSession.getApplication().findConcern(configurationClass));
	}

}