1 files changed, 46 insertions, 0 deletions
diff --git a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/query/ExpressionQuery.java b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/query/ExpressionQuery.java
new file mode 100644
index 000000000..ea0cb676b
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/query/ExpressionQuery.java
@@ -0,0 +1,46 @@
+/*******************************************************************************
+ *  Copyright (c) 2007, 2009 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.equinox.p2.metadata.query;
+
+import org.eclipse.equinox.internal.p2.metadata.expression.ExpressionFactory;
+import org.eclipse.equinox.p2.metadata.expression.*;
+import org.eclipse.equinox.p2.query.MatchQuery;
+
+/**
+ * A query that matches candidates against an expression.
+ */
+public class ExpressionQuery<T> extends MatchQuery<T> {
+	private final IMatchExpression<T> expression;
+	private final IEvaluationContext context;
+	private final Class<T> matchingClass;
+
+	public ExpressionQuery(Class<T> matchingClass, IExpression expression, Object... parameters) {
+		this(matchingClass, ExpressionUtil.getFactory().<T> matchExpression(expression, parameters));
+	}
+
+	public ExpressionQuery(Class<T> matchingClass, IMatchExpression<T> expression) {
+		this.matchingClass = matchingClass;
+		this.expression = expression;
+		this.context = expression.createContext();
+	}
+
+	@Override
+	public boolean isMatch(T candidate) {
+		if (!matchingClass.isInstance(candidate))
+			return false;
+		ExpressionFactory.THIS.setValue(context, candidate);
+		return Boolean.TRUE == expression.evaluate(context);
+	}
+
+	public IMatchExpression<T> getExpression() {
+		return expression;
+	}
+}