| /******************************************************************************* |
| * Copyright (c) 2009, 2010 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; |
| |
| /** |
| * A collection filter that yields the first element of the <code>collection</code> for which |
| * the <code>filter</code> yields <code>true</code> |
| */ |
| final class First extends CollectionFilter { |
| First(Expression collection, LambdaExpression lambda) { |
| super(collection, lambda); |
| } |
| |
| protected Object evaluate(IEvaluationContext context, Iterator<?> itor) { |
| Variable variable = lambda.getItemVariable(); |
| while (itor.hasNext()) { |
| Object each = itor.next(); |
| variable.setValue(context, each); |
| if (lambda.evaluate(context) == Boolean.TRUE) |
| return each; |
| } |
| return null; |
| } |
| |
| public int getExpressionType() { |
| return TYPE_FIRST; |
| } |
| |
| public String getOperator() { |
| return KEYWORD_FIRST; |
| } |
| } |