ModuleCollisionHook.java

/*******************************************************************************
 * Copyright (c) 2012 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.osgi.container;

import java.util.Collection;

/**
 * Hook used to determine if a module revision being installed or updated will cause a collision
 * @since 3.10
 */
public interface ModuleCollisionHook {

	/**
	 * Specifies a module install operation is being performed.
	 */
	int INSTALLING = 1;

	/**
	 * Specifies a module update operation is being performed.
	 */
	int UPDATING = 2;

	/**
	 * Filter bundle collisions hook method. This method is called during the
	 * install or update operation. The operation type will be
	 * {@link #INSTALLING installing} or {@link #UPDATING updating}. Depending
	 * on the operation type the target module and the collision candidate
	 * collection are the following:
	 * <ul>
	 * <li> {@link #INSTALLING installing} - The target is the module associated
	 * which is performing the install operation. The
	 * collision candidate collection contains the existing modules installed
	 * which have a current revision with the same symbolic name and version as the 
	 * module being installed.
	 * <li> {@link #UPDATING updating} - The target is the module being updated. 
	 * The collision candidate collection contains the existing modules installed which have
	 * a current revision with the same symbolic name and version as the content the target 
	 * module is being updated to.
	 * </ul>
	 * This method can filter the collection of collision candidates by removing
	 * potential collisions. For the specified operation to succeed, the
	 * collection of collision candidates must be empty when this method returns.
	 * 
	 * @param operationType The operation type. Must be the value of
	 *        {@link #INSTALLING installing} or {@link #UPDATING updating}.
	 * @param target The target module used to determine what collision
	 *        candidates to filter.
	 * @param collisionCandidates The collection of collision candidates.
	 */
	void filterCollisions(int operationType, Module target, Collection<Module> collisionCandidates);
}