Merging api branch back to HEADv20100113

1 files changed, 85 insertions, 0 deletions

diff --git a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/internal/p2/metadata/expression/CollectionFilter.java b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/internal/p2/metadata/expression/CollectionFilter.java
new file mode 100644
index 000000000..bb845d373
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/internal/p2/metadata/expression/CollectionFilter.java
@@ -0,0 +1,85 @@
+/*******************************************************************************
+ * Copyright (c) 2009 Cloudsmith Inc. 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:
+ *     Cloudsmith Inc. - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.equinox.internal.p2.metadata.expression;
+
+import java.util.Iterator;
+import org.eclipse.equinox.p2.metadata.expression.IEvaluationContext;
+import org.eclipse.equinox.p2.metadata.expression.IExpressionVisitor;
+
+/**
+ * Some kind of operation that is performed for each element of a collection. I.e.
+ * <code>x.&lt;operation&gt;(y | &lt;expression&rt;)</code>
+ */
+public abstract class CollectionFilter extends Unary {
+	public static void appendProlog(StringBuffer bld, Variable rootVariable, Expression lhs, String operator) {
+		if (lhs != rootVariable) {
+			appendOperand(bld, rootVariable, lhs, PRIORITY_COLLECTION);
+			bld.append('.');
+		}
+		bld.append(operator);
+		bld.append('(');
+	}
+
+	public final LambdaExpression lambda;
+
+	protected CollectionFilter(Expression collection, LambdaExpression lambda) {
+		super(collection);
+		this.lambda = lambda;
+	}
+
+	public boolean accept(IExpressionVisitor visitor) {
+		return super.accept(visitor) && lambda.accept(visitor);
+	}
+
+	public int compareTo(Expression e) {
+		int cmp = super.compareTo(e);
+		if (cmp == 0)
+			cmp = lambda.compareTo(((CollectionFilter) e).lambda);
+		return cmp;
+	}
+
+	public boolean equals(Object o) {
+		return super.equals(o) && lambda.equals(((CollectionFilter) o).lambda);
+	}
+
+	public final Object evaluate(IEvaluationContext context) {
+		Iterator<?> lval = operand.evaluateAsIterator(context);
+		context = lambda.prolog(context);
+		return evaluate(context, lval);
+	}
+
+	public final Iterator<?> evaluateAsIterator(IEvaluationContext context) {
+		Iterator<?> lval = operand.evaluateAsIterator(context);
+		context = lambda.prolog(context);
+		return evaluateAsIterator(context, lval);
+	}
+
+	public void toString(StringBuffer bld, Variable rootVariable) {
+		appendProlog(bld, rootVariable, operand, getOperator());
+		appendOperand(bld, rootVariable, lambda, PRIORITY_LAMBDA);
+		bld.append(')');
+	}
+
+	public int hashCode() {
+		int result = 31 + operand.hashCode();
+		return 31 * result + lambda.hashCode();
+	}
+
+	public int getPriority() {
+		return PRIORITY_COLLECTION;
+	}
+
+	protected abstract Object evaluate(final IEvaluationContext context, Iterator<?> iterator);
+
+	protected Iterator<?> evaluateAsIterator(IEvaluationContext context, Iterator<?> iterator) {
+		throw new UnsupportedOperationException();
+	}
+}