1 files changed, 147 insertions, 0 deletions
diff --git a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/query/CompoundQueryable.java b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/query/CompoundQueryable.java
new file mode 100644
index 000000000..bbfd2bd20
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/query/CompoundQueryable.java
@@ -0,0 +1,147 @@
+/******************************************************************************* 
+* Copyright (c) 2009 EclipseSource 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:
+*   EclipseSource - initial API and implementation
+******************************************************************************/
+package org.eclipse.equinox.p2.query;
+
+import java.lang.reflect.Array;
+import java.util.*;
+import org.eclipse.core.runtime.*;
+import org.eclipse.equinox.internal.p2.core.helpers.CollectionUtils;
+
+/**
+ * A queryable that holds a number of other IQueryables and provides
+ * a mechanism for querying the entire set.
+ * @since 2.0
+ */
+public class CompoundQueryable<T> implements IQueryable<T> {
+
+	private IQueryable<T>[] queryables;
+
+	private CompoundQueryable(IQueryable<T>[] queryables) {
+		this.queryables = queryables;
+	}
+
+	@SuppressWarnings("unchecked")
+	public CompoundQueryable(Collection<? extends IQueryable<T>> queryables) {
+		this(queryables.toArray(new IQueryable[queryables.size()]));
+	}
+
+	@SuppressWarnings("unchecked")
+	public CompoundQueryable(IQueryable<T> q) {
+		this(new IQueryable[] {q});
+	}
+
+	@SuppressWarnings("unchecked")
+	public CompoundQueryable(IQueryable<T> q1, IQueryable<T> q2) {
+		this(new IQueryable[] {q1, q2});
+	}
+
+	@SuppressWarnings("unchecked")
+	public CompoundQueryable(IQueryable<T> q1, IQueryable<T> q2, IQueryable<T> q3) {
+		this(new IQueryable[] {q1, q2, q3});
+	}
+
+	public IQueryResult<T> query(IQuery<T> query, IProgressMonitor monitor) {
+		IQueryResult<T> subResults = null;
+		if (monitor == null) {
+			monitor = new NullProgressMonitor();
+		}
+		boolean isMatchQuery = query instanceof IMatchQuery<?>;
+		int totalWork = isMatchQuery ? queryables.length : queryables.length + 1;
+
+		try {
+			SubMonitor subMonitor = SubMonitor.convert(monitor, totalWork * 10);
+			Collector<T> results;
+			if (!isMatchQuery) {
+				// If it is not a match query, then collect the results
+				// as a list, we will query this list for the final results
+				results = new ListCollector<T>();
+			} else
+				results = new Collector<T>();
+
+			for (int i = 0; i < queryables.length; i++) {
+				if (subMonitor.isCanceled())
+					break;
+				subResults = queryables[i].query(query, subMonitor.newChild(10));
+				results.addAll(subResults);
+			}
+
+			if (isMatchQuery)
+				return results;
+
+			// If it is not a MatchQuery then we must query the results.
+			return results.query(query, subMonitor.newChild(10));
+		} finally {
+			monitor.done();
+		}
+	}
+
+	/**
+	 * A list collector.
+	 * 
+	 * This is a collector backed as a list.
+	 * 
+	 * The list collector is not intended to be used outside of this class.  It is only public
+	 * for testing purposes.
+	 * 
+	 * @noinstantiate This class is not intended to be instantiated by clients.
+	 * @noextend This class is not intended to be subclassed by clients.
+	 * 
+	 */
+	public static class ListCollector<T> extends Collector<T> {
+		private List<T> collected;
+
+		public ListCollector() {
+			super();
+		}
+
+		protected Collection<T> getCollection() {
+			if (collected == null)
+				collected = new ArrayList<T>();
+			return collected;
+		}
+
+		public boolean isEmpty() {
+			return collected == null || collected.isEmpty();
+		}
+
+		@SuppressWarnings("unchecked")
+		public T[] toArray(Class<? extends T> clazz) {
+			int size = collected == null ? 0 : collected.size();
+			T[] result = (T[]) Array.newInstance(clazz, size);
+			if (size != 0)
+				collected.toArray(result);
+			return result;
+		}
+
+		public boolean accept(T object) {
+			if (collected == null)
+				collected = new ArrayList<T>();
+			collected.add(object);
+			return true;
+		}
+
+		/**
+		 * Returns the collected objects as an immutable collection.
+		 * 
+		 * @return An unmodifiable collection of the collected objects
+		 */
+		public Set<T> toSet() {
+			return collected == null ? new HashSet<T>() : new HashSet<T>(collected);
+		}
+
+		public Iterator<T> iterator() {
+			return collected == null ? CollectionUtils.<T> emptyList().iterator() : collected.iterator();
+		}
+
+		public int size() {
+			return collected == null ? 0 : collected.size();
+		}
+	}
+}