bundles/org.eclipse.equinox.p2.ui/src/org/eclipse/equinox/internal/p2/ui/query/RequiredIUsQuery.java

/*******************************************************************************
 *  Copyright (c) 2010 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
 *     Cloudsmith Inc. - converted into expression based query
 *******************************************************************************/
package org.eclipse.equinox.internal.p2.ui.query;

import org.eclipse.equinox.p2.query.ExpressionMatchQuery;

import org.eclipse.equinox.p2.metadata.IInstallableUnit;
import org.eclipse.equinox.p2.metadata.expression.ExpressionUtil;
import org.eclipse.equinox.p2.metadata.expression.IExpression;

/**
/**
 * A query matching every {@link IInstallableUnit} that is meets
 * any requirement of the specified IU.  This query is used when
 * drilling down to show the children of an available IU.  For example,
 * when installing an IU, we want to show all the IU's that are in the provisioning
 * plan that are required by this IU.  This is usually used in combination with
 * other queries (such as show all Required IUs which also are visible to
 * the user as available).
 * 
 * @since 2.0 
 */
public class RequiredIUsQuery extends ExpressionMatchQuery<IInstallableUnit> {

	private static final IExpression expression = ExpressionUtil.parse("$0.exists(rc | this ~= rc)"); //$NON-NLS-1$

	/**
	 * Creates a new query that will return any IU that meets any
	 * one of the requirements of the specified IU. 
	 * 
	 * @param iu The IU whose requirements are to be checked
	 */
	public RequiredIUsQuery(IInstallableUnit iu) {
		super(IInstallableUnit.class, expression, iu.getRequirements());
	}
}