org.scijava.plugin.AbstractSingletonService Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of scijava-common Show documentation

SciJava Common is a shared library for SciJava software. It provides a plugin framework, with an extensible mechanism for service discovery, backed by its own annotation processor, so that plugins can be loaded dynamically. It is used by both ImageJ and SCIFIO.

There is a newer version: 2.99.0

Show newest version

/*
 * #%L
 * SciJava Common shared library for SciJava software.
 * %%
 * Copyright (C) 2009 - 2016 Board of Regents of the University of
 * Wisconsin-Madison, Broad Institute of MIT and Harvard, and Max Planck
 * Institute of Molecular Cell Biology and Genetics.
 * %%
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * #L%
 */

package org.scijava.plugin;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.scijava.log.LogService;
import org.scijava.object.LazyObjects;
import org.scijava.object.ObjectService;

/**
 * Abstract base class for {@link SingletonService}s.
 * 
 * @author Curtis Rueden
 * @param  Plugin type of the {@link SingletonPlugin}s being managed.
 */
public abstract class AbstractSingletonService
	extends AbstractPTService implements SingletonService
{

	@Parameter
	private LogService log;

	@Parameter
	private ObjectService objectService;

	// TODO: Listen for PluginsAddedEvent and PluginsRemovedEvent
	// and update the list of singletons accordingly.

	/** List of singleton plugin instances. */
	private List instances;

	private Map, PT> instanceMap;

	// -- SingletonService methods --

	@Override
	public List getInstances() {
		if (instances == null) initInstances();
		return instances;
	}

	@SuppressWarnings("unchecked")
	@Override
	public  P getInstance(final Class
 pluginClass) {
		if (instanceMap == null) initInstances();
		return (P) instanceMap.get(pluginClass);
	}

	// -- PTService methods --

	@Override
	public 
 P create(final Class
 pluginClass) {
		throw new UnsupportedOperationException(
			"Cannot create singleton plugin instance. "
				+ "Use getInstance(Class) instead.");
	}

	// -- Service methods --

	@Override
	public void initialize() {
		// add singleton instances to the object index... IN THE FUTURE!
		objectService.getIndex().addLater(new LazyObjects