org.apache.ace.client.repository/src/org/apache/ace/client/repository/impl/AssociationImpl.java - ace - Git at Google

 /*
  * 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.
  */
 package org.apache.ace.client.repository.impl;

 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
 import java.util.Properties;

 import org.apache.ace.client.repository.Associatable;
 import org.apache.ace.client.repository.Association;
 import org.apache.ace.client.repository.RepositoryObject;
 import org.osgi.framework.Filter;
 import org.osgi.framework.InvalidSyntaxException;
 import org.osgi.service.event.Event;

 import com.thoughtworks.xstream.io.HierarchicalStreamReader;

 /**
  * A basic implementation of the Association interface. Implements 'common' behavior for all associations.
  *
  * The association allows up to m-to-n associations. Each end of the association gets
  * a filter to match objects, possibly a cardinality (if no cardinality is specified,
  * 1 is assumed), and, if there can be more matches to the filter than the given cardinality,
  * a comparator should be provided in the constructor.
  *
  * @param <L> The type of the RepositoryObject on the left side of this association
  * @param <R> The type of the RepositoryObject on the right side of this association
  * @param <T> The non-generic Association interface this object should use.
  */
 public class AssociationImpl<L extends RepositoryObject, R extends RepositoryObject, T extends Association<L, R>> extends RepositoryObjectImpl<T> implements Association<L, R> {

     /* These lists are volatile, since we use copy-on-write semantics for
      * updating them.
      */
     private volatile List<L> m_left = new ArrayList<>();
     private volatile List<R> m_right = new ArrayList<>();
     private final Object m_lock = new Object();

     private final Filter m_filterLeft;
     private final Filter m_filterRight;

     private final ObjectRepositoryImpl<?, L> m_leftRepository;
     private final ObjectRepositoryImpl<?, R> m_rightRepository;
     private final Class<L> m_leftClass;
     private final Class<R> m_rightClass;

     /**
      * Constructor intended for deserialization. For most parameters, see below.
      * @param reader a stream reader which contains an XML representation of this object's contents.
      */
     public AssociationImpl(HierarchicalStreamReader reader, ChangeNotifier notifier, Class<L> leftClass, Class<R> rightClass, Comparator<L> leftComparator, Comparator<R> rightComparator, ObjectRepositoryImpl<?, L> leftRepository, ObjectRepositoryImpl<?, R> rightRepository, String xmlNode) throws InvalidSyntaxException {
         this(readMap(reader), notifier, leftClass, rightClass, leftRepository, rightRepository, xmlNode);
     }

     /**
      * Basic constructor for AssociationImpl.
      * @param attributes A map of attributes. This should at least contain <code>Association.LEFT_ENDPOINT</code> and <code>Association.RIGHT_ENDPOINT</code>,
      * and optionally <code>Association.LEFT_CARDINALITY</code> and <code>Association.RIGHT_CARDINALITY</code>.
      * @param notifier An instance of the event admin
      * @param leftClass The class on the left side of this association.
      * @param rightClass The class on the right side of this association.
      * @param leftRepository The repository which holds object of <code>leftClass</code>.
      * @param rightRepository The repository which holds object of <code>rightClass</code>.
      * @param xmlNode The tag by which this object is known in the XML representation.
      * @throws InvalidSyntaxException Thrown when the attributes contain an invalidly constructed filter string.
      */
     public AssociationImpl(Map<String, String> attributes, ChangeNotifier notifier, Class<L> leftClass, Class<R> rightClass, ObjectRepositoryImpl<?, L> leftRepository, ObjectRepositoryImpl<?, R> rightRepository, String xmlNode) throws InvalidSyntaxException {
         super(attributes, notifier, xmlNode);

         if ((getAttribute(LEFT_CARDINALITY) != null) && (Integer.parseInt(getAttribute(LEFT_CARDINALITY)) < 1)) {
             throw new IllegalArgumentException("The left cardinality should be 1 or greater.");
         }
         if ((getAttribute(RIGHT_CARDINALITY) != null) && (Integer.parseInt(getAttribute(RIGHT_CARDINALITY)) < 1)) {
             throw new IllegalArgumentException("The right cardinality should be 1 or greater.");
         }

         m_leftClass = leftClass;
         m_rightClass = rightClass;
         m_leftRepository = leftRepository;
         m_rightRepository = rightRepository;

         m_filterLeft = m_leftRepository.createFilter(getAttribute(Association.LEFT_ENDPOINT));
         m_filterRight = m_rightRepository.createFilter(getAttribute(Association.RIGHT_ENDPOINT));

         locateLeftEndpoint(false);
         locateRightEndpoint(false);
     }

     public AssociationImpl(Map<String, String> attributes, Map<String, String> tags, ChangeNotifier notifier, Class<L> leftClass, Class<R> rightClass, ObjectRepositoryImpl<?, L> leftRepository, ObjectRepositoryImpl<?, R> rightRepository, String xmlNode) throws InvalidSyntaxException {
         super(attributes, tags, notifier, xmlNode);

         if ((getAttribute(LEFT_CARDINALITY) != null) && (Integer.parseInt(getAttribute(LEFT_CARDINALITY)) < 1)) {
             throw new IllegalArgumentException("The left cardinality should be 1 or greater.");
         }
         if ((getAttribute(RIGHT_CARDINALITY) != null) && (Integer.parseInt(getAttribute(RIGHT_CARDINALITY)) < 1)) {
             throw new IllegalArgumentException("The right cardinality should be 1 or greater.");
         }

         m_leftClass = leftClass;
         m_rightClass = rightClass;
         m_leftRepository = leftRepository;
         m_rightRepository = rightRepository;

         m_filterLeft = m_leftRepository.createFilter(getAttribute(Association.LEFT_ENDPOINT));
         m_filterRight = m_rightRepository.createFilter(getAttribute(Association.RIGHT_ENDPOINT));

         locateLeftEndpoint(false);
         locateRightEndpoint(false);
     }

     public List<Associatable> getTo(Associatable from) {
         if (m_left.contains(from)) {
             return new ArrayList<Associatable>(m_right);
         }
         if (m_right.contains(from)) {
             return new ArrayList<Associatable>(m_left);
         }
         return null;
     }

     public List<L> getLeft() {
         return new ArrayList<>(m_left);
     }

     public List<R> getRight() {
         return new ArrayList<>(m_right);
     }

     public void remove() {
         for (L l : m_left) {
             l.remove(this, m_rightClass);
         }
         for (R r : m_right) {
             r.remove(this, m_leftClass);
         }
     }

     /**
      * Locates the most suited endpoint of one side of this association. If the corresponding filter
      * matches multiple objects, the <code>comparator</code> will be used to find the most suited one.
      * The association will register itself with a new endpoint, and remove itself from the old one.
      * @param <TYPE> (only used for type matching).
      * @param objectRepositoryImpl The repository where the endpoint should come from.
      * @param filter A filter string, used to get candidate-endpoints from <code>objectRepositoryImpl</code>.
      * @param endpoint The current endpoint.
      * @param comparator A comparator, used when there are multiple potential endpoints.
      * @param clazz The class of the 'other side' of this association.
      * @return The most suited endpoint; this could be equal to <code>endpoint</code>.
      */
     private <TYPE extends RepositoryObject> List<TYPE> locateEndpoint(ObjectRepositoryImpl<?, TYPE> objectRepositoryImpl, Filter filter, List<TYPE> endpoints, int cardinality, Class<? extends RepositoryObject> clazz, boolean notify) {

         List<TYPE> candidates = objectRepositoryImpl.get(filter);
         if (candidates.size() > cardinality) {
             Comparator<TYPE> comparator = candidates.get(0).getComparator();
             if (comparator != null) {
                 Collections.sort(candidates, comparator);
             }
             else {
                 throw new NullPointerException("Filter '" + filter.toString() + "' in '" + this + "' has resulted in multiple candidates, so the RepositoryObject descendents should have provide a comparator, which they do not.");
             }
         }

         List<TYPE> oldEndpoints = new ArrayList<>(endpoints);
         List<TYPE> newEndpoints = new ArrayList<>();
         for (int i = 0; (i < cardinality) && !candidates.isEmpty(); i++) {
             TYPE current = candidates.remove(0);
             newEndpoints.add(current);
             if (!oldEndpoints.remove(current)) {
                 current.add(this, clazz);
             }
         }
         for (TYPE e : oldEndpoints) {
             e.remove(this, clazz);
         }
         return newEndpoints;
     }

     /**
      * Locates the left endpoint by using the generic locateEndpoint and notifies
      * listeners of changes, if any.
      * @param notify Indicates whether notifications should be sent out.
      */
     private void locateLeftEndpoint(boolean notify) {
         synchronized (m_lock) {
             List<L> newEndpoints = locateEndpoint(m_leftRepository, m_filterLeft, m_left, (getAttribute(LEFT_CARDINALITY) == null ? 1 : Integer.parseInt(getAttribute(LEFT_CARDINALITY))), m_rightClass, notify);
             if (!newEndpoints.equals(m_left)) {
                 if (notify) {
                     List<L> oldEndpoints = new ArrayList<>(m_left);
                     m_left = new ArrayList<>(newEndpoints);
                     Properties props = new Properties();
                     props.put(EVENT_OLD, oldEndpoints);
                     props.put(EVENT_NEW, newEndpoints);
                     notifyChanged(props);
                 }
                 else {
                     m_left = newEndpoints;
                 }
             }
         }
     }

     /**
      * Locates the right endpoint by using the generic locateEndpoint and notifies
      * listeners of changes, if any.
      * @param notify Indicates whether notifications should be sent out.
      */
     private void locateRightEndpoint(boolean notify) {
         synchronized (m_lock) {
             List<R> newEndpoints = locateEndpoint(m_rightRepository, m_filterRight, m_right, (getAttribute(RIGHT_CARDINALITY) == null ? 1 : Integer.parseInt(getAttribute(RIGHT_CARDINALITY))), m_leftClass, notify);
             if (!newEndpoints.equals(m_right)) {
                 if (notify) {
                     List<R> oldEndpoints = new ArrayList<>(m_right);
                     m_right = new ArrayList<>(newEndpoints);
                     Properties props = new Properties();
                     props.put(EVENT_OLD, oldEndpoints);
                     props.put(EVENT_NEW, newEndpoints);
                     notifyChanged(props);
                 }
                 else {
                     m_right = newEndpoints;
                 }
             }
         }
     }

     public boolean isSatisfied() {
         return (!m_left.isEmpty()) && (!m_right.isEmpty());
     }

     @Override
     public void handleEvent(Event event) {
         // We get a topic which ends in '/*', but the event contains a specialized topic.
         // for now, we chop of the star, and check whether the topic starts with that.
         RepositoryObject entity = (RepositoryObject) event.getProperty(RepositoryObject.EVENT_ENTITY);
         if ((event.getTopic().endsWith("ADDED")) || event.getTopic().endsWith("REMOVED")) {
             if (m_leftClass.isInstance(entity) && m_filterLeft.matchCase(entity.getDictionary())) {
                 locateLeftEndpoint(true);
             }
             if (m_rightClass.isInstance(entity) && m_filterRight.matchCase(entity.getDictionary())) {
                 locateRightEndpoint(true);
             }
         }
     }
 }
	/*
	* 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.
	*/
	package org.apache.ace.client.repository.impl;

	import java.util.ArrayList;
	import java.util.Collections;
	import java.util.Comparator;
	import java.util.List;
	import java.util.Map;
	import java.util.Properties;

	import org.apache.ace.client.repository.Associatable;
	import org.apache.ace.client.repository.Association;
	import org.apache.ace.client.repository.RepositoryObject;
	import org.osgi.framework.Filter;
	import org.osgi.framework.InvalidSyntaxException;
	import org.osgi.service.event.Event;

	import com.thoughtworks.xstream.io.HierarchicalStreamReader;

	/**
	* A basic implementation of the Association interface. Implements 'common' behavior for all associations.
	*
	* The association allows up to m-to-n associations. Each end of the association gets
	* a filter to match objects, possibly a cardinality (if no cardinality is specified,
	* 1 is assumed), and, if there can be more matches to the filter than the given cardinality,
	* a comparator should be provided in the constructor.
	*
	* @param <L> The type of the RepositoryObject on the left side of this association
	* @param <R> The type of the RepositoryObject on the right side of this association
	* @param <T> The non-generic Association interface this object should use.
	*/
	public class AssociationImpl<L extends RepositoryObject, R extends RepositoryObject, T extends Association<L, R>> extends RepositoryObjectImpl<T> implements Association<L, R> {

	/* These lists are volatile, since we use copy-on-write semantics for
	* updating them.
	*/
	private volatile List<L> m_left = new ArrayList<>();
	private volatile List<R> m_right = new ArrayList<>();
	private final Object m_lock = new Object();

	private final Filter m_filterLeft;
	private final Filter m_filterRight;

	private final ObjectRepositoryImpl<?, L> m_leftRepository;
	private final ObjectRepositoryImpl<?, R> m_rightRepository;
	private final Class<L> m_leftClass;
	private final Class<R> m_rightClass;

	/**
	* Constructor intended for deserialization. For most parameters, see below.
	* @param reader a stream reader which contains an XML representation of this object's contents.
	*/
	public AssociationImpl(HierarchicalStreamReader reader, ChangeNotifier notifier, Class<L> leftClass, Class<R> rightClass, Comparator<L> leftComparator, Comparator<R> rightComparator, ObjectRepositoryImpl<?, L> leftRepository, ObjectRepositoryImpl<?, R> rightRepository, String xmlNode) throws InvalidSyntaxException {
	this(readMap(reader), notifier, leftClass, rightClass, leftRepository, rightRepository, xmlNode);
	}

	/**
	* Basic constructor for AssociationImpl.
	* @param attributes A map of attributes. This should at least contain <code>Association.LEFT_ENDPOINT</code> and <code>Association.RIGHT_ENDPOINT</code>,
	* and optionally <code>Association.LEFT_CARDINALITY</code> and <code>Association.RIGHT_CARDINALITY</code>.
	* @param notifier An instance of the event admin
	* @param leftClass The class on the left side of this association.
	* @param rightClass The class on the right side of this association.
	* @param leftRepository The repository which holds object of <code>leftClass</code>.
	* @param rightRepository The repository which holds object of <code>rightClass</code>.
	* @param xmlNode The tag by which this object is known in the XML representation.
	* @throws InvalidSyntaxException Thrown when the attributes contain an invalidly constructed filter string.
	*/
	public AssociationImpl(Map<String, String> attributes, ChangeNotifier notifier, Class<L> leftClass, Class<R> rightClass, ObjectRepositoryImpl<?, L> leftRepository, ObjectRepositoryImpl<?, R> rightRepository, String xmlNode) throws InvalidSyntaxException {
	super(attributes, notifier, xmlNode);

	if ((getAttribute(LEFT_CARDINALITY) != null) && (Integer.parseInt(getAttribute(LEFT_CARDINALITY)) < 1)) {
	throw new IllegalArgumentException("The left cardinality should be 1 or greater.");
	}
	if ((getAttribute(RIGHT_CARDINALITY) != null) && (Integer.parseInt(getAttribute(RIGHT_CARDINALITY)) < 1)) {
	throw new IllegalArgumentException("The right cardinality should be 1 or greater.");
	}

	m_leftClass = leftClass;
	m_rightClass = rightClass;
	m_leftRepository = leftRepository;
	m_rightRepository = rightRepository;

	m_filterLeft = m_leftRepository.createFilter(getAttribute(Association.LEFT_ENDPOINT));
	m_filterRight = m_rightRepository.createFilter(getAttribute(Association.RIGHT_ENDPOINT));

	locateLeftEndpoint(false);
	locateRightEndpoint(false);
	}

	public AssociationImpl(Map<String, String> attributes, Map<String, String> tags, ChangeNotifier notifier, Class<L> leftClass, Class<R> rightClass, ObjectRepositoryImpl<?, L> leftRepository, ObjectRepositoryImpl<?, R> rightRepository, String xmlNode) throws InvalidSyntaxException {
	super(attributes, tags, notifier, xmlNode);

	if ((getAttribute(LEFT_CARDINALITY) != null) && (Integer.parseInt(getAttribute(LEFT_CARDINALITY)) < 1)) {
	throw new IllegalArgumentException("The left cardinality should be 1 or greater.");
	}
	if ((getAttribute(RIGHT_CARDINALITY) != null) && (Integer.parseInt(getAttribute(RIGHT_CARDINALITY)) < 1)) {
	throw new IllegalArgumentException("The right cardinality should be 1 or greater.");
	}

	m_leftClass = leftClass;
	m_rightClass = rightClass;
	m_leftRepository = leftRepository;
	m_rightRepository = rightRepository;

	m_filterLeft = m_leftRepository.createFilter(getAttribute(Association.LEFT_ENDPOINT));
	m_filterRight = m_rightRepository.createFilter(getAttribute(Association.RIGHT_ENDPOINT));

	locateLeftEndpoint(false);
	locateRightEndpoint(false);
	}

	public List<Associatable> getTo(Associatable from) {
	if (m_left.contains(from)) {
	return new ArrayList<Associatable>(m_right);
	}
	if (m_right.contains(from)) {
	return new ArrayList<Associatable>(m_left);
	}
	return null;
	}

	public List<L> getLeft() {
	return new ArrayList<>(m_left);
	}

	public List<R> getRight() {
	return new ArrayList<>(m_right);
	}

	public void remove() {
	for (L l : m_left) {
	l.remove(this, m_rightClass);
	}
	for (R r : m_right) {
	r.remove(this, m_leftClass);
	}
	}

	/**
	* Locates the most suited endpoint of one side of this association. If the corresponding filter
	* matches multiple objects, the <code>comparator</code> will be used to find the most suited one.
	* The association will register itself with a new endpoint, and remove itself from the old one.
	* @param <TYPE> (only used for type matching).
	* @param objectRepositoryImpl The repository where the endpoint should come from.
	* @param filter A filter string, used to get candidate-endpoints from <code>objectRepositoryImpl</code>.
	* @param endpoint The current endpoint.
	* @param comparator A comparator, used when there are multiple potential endpoints.
	* @param clazz The class of the 'other side' of this association.
	* @return The most suited endpoint; this could be equal to <code>endpoint</code>.
	*/
	private <TYPE extends RepositoryObject> List<TYPE> locateEndpoint(ObjectRepositoryImpl<?, TYPE> objectRepositoryImpl, Filter filter, List<TYPE> endpoints, int cardinality, Class<? extends RepositoryObject> clazz, boolean notify) {

	List<TYPE> candidates = objectRepositoryImpl.get(filter);
	if (candidates.size() > cardinality) {
	Comparator<TYPE> comparator = candidates.get(0).getComparator();
	if (comparator != null) {
	Collections.sort(candidates, comparator);
	}
	else {
	throw new NullPointerException("Filter '" + filter.toString() + "' in '" + this + "' has resulted in multiple candidates, so the RepositoryObject descendents should have provide a comparator, which they do not.");
	}
	}

	List<TYPE> oldEndpoints = new ArrayList<>(endpoints);
	List<TYPE> newEndpoints = new ArrayList<>();
	for (int i = 0; (i < cardinality) && !candidates.isEmpty(); i++) {
	TYPE current = candidates.remove(0);
	newEndpoints.add(current);
	if (!oldEndpoints.remove(current)) {
	current.add(this, clazz);
	}
	}
	for (TYPE e : oldEndpoints) {
	e.remove(this, clazz);
	}
	return newEndpoints;
	}

	/**
	* Locates the left endpoint by using the generic locateEndpoint and notifies
	* listeners of changes, if any.
	* @param notify Indicates whether notifications should be sent out.
	*/
	private void locateLeftEndpoint(boolean notify) {
	synchronized (m_lock) {
	List<L> newEndpoints = locateEndpoint(m_leftRepository, m_filterLeft, m_left, (getAttribute(LEFT_CARDINALITY) == null ? 1 : Integer.parseInt(getAttribute(LEFT_CARDINALITY))), m_rightClass, notify);
	if (!newEndpoints.equals(m_left)) {
	if (notify) {
	List<L> oldEndpoints = new ArrayList<>(m_left);
	m_left = new ArrayList<>(newEndpoints);
	Properties props = new Properties();
	props.put(EVENT_OLD, oldEndpoints);
	props.put(EVENT_NEW, newEndpoints);
	notifyChanged(props);
	}
	else {
	m_left = newEndpoints;
	}
	}
	}
	}

	/**
	* Locates the right endpoint by using the generic locateEndpoint and notifies
	* listeners of changes, if any.
	* @param notify Indicates whether notifications should be sent out.
	*/
	private void locateRightEndpoint(boolean notify) {
	synchronized (m_lock) {
	List<R> newEndpoints = locateEndpoint(m_rightRepository, m_filterRight, m_right, (getAttribute(RIGHT_CARDINALITY) == null ? 1 : Integer.parseInt(getAttribute(RIGHT_CARDINALITY))), m_leftClass, notify);
	if (!newEndpoints.equals(m_right)) {
	if (notify) {
	List<R> oldEndpoints = new ArrayList<>(m_right);
	m_right = new ArrayList<>(newEndpoints);
	Properties props = new Properties();
	props.put(EVENT_OLD, oldEndpoints);
	props.put(EVENT_NEW, newEndpoints);
	notifyChanged(props);
	}
	else {
	m_right = newEndpoints;
	}
	}
	}
	}

	public boolean isSatisfied() {
	return (!m_left.isEmpty()) && (!m_right.isEmpty());
	}

	@Override
	public void handleEvent(Event event) {
	// We get a topic which ends in '/*', but the event contains a specialized topic.
	// for now, we chop of the star, and check whether the topic starts with that.
	RepositoryObject entity = (RepositoryObject) event.getProperty(RepositoryObject.EVENT_ENTITY);
	if ((event.getTopic().endsWith("ADDED")) \|\| event.getTopic().endsWith("REMOVED")) {
	if (m_leftClass.isInstance(entity) && m_filterLeft.matchCase(entity.getDictionary())) {
	locateLeftEndpoint(true);
	}
	if (m_rightClass.isInstance(entity) && m_filterRight.matchCase(entity.getDictionary())) {
	locateRightEndpoint(true);
	}
	}
	}
	}