| /******************************************************************************* |
| * 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.Collection; |
| import java.util.Iterator; |
| import org.eclipse.equinox.internal.p2.core.helpers.CollectionUtils; |
| import org.eclipse.equinox.p2.metadata.index.IIndexProvider; |
| |
| /** |
| * The immutable context used when evaluating an expression. |
| */ |
| public final class Everything<T> extends MatchIteratorFilter<T> implements IRepeatableIterator<T> { |
| private boolean atStart = true; |
| |
| private final Class<? extends T> elementClass; |
| |
| public Everything(Class<? extends T> elementClass, Collection<T> collection) { |
| super(RepeatableIterator.<T> create(collection == null ? CollectionUtils.<T> emptyList() : collection)); |
| this.elementClass = elementClass; |
| } |
| |
| public Everything(Class<? extends T> elementClass, Iterator<? extends T> iterator, Expression expression) { |
| this(elementClass, iterator, needsRepeadedAccessToEverything(expression)); |
| } |
| |
| public Everything(Class<? extends T> elementClass, IIndexProvider<? extends T> indexProvider) { |
| super(RepeatableIterator.<T> create(indexProvider)); |
| this.elementClass = elementClass; |
| } |
| |
| Everything(Class<? extends T> elementClass, Iterator<? extends T> iterator, boolean needsRepeat) { |
| super(needsRepeat ? RepeatableIterator.create(iterator) : iterator); |
| this.elementClass = elementClass; |
| } |
| |
| public IRepeatableIterator<T> getCopy() { |
| Iterator<? extends T> iterator = getInnerIterator(); |
| if (iterator instanceof IRepeatableIterator<?>) |
| return new Everything<T>(elementClass, ((IRepeatableIterator<? extends T>) iterator).getCopy(), false); |
| if (atStart) |
| return this; |
| throw new UnsupportedOperationException(); |
| } |
| |
| public T next() { |
| atStart = false; |
| return super.next(); |
| } |
| |
| public Class<? extends T> getElementClass() { |
| return elementClass; |
| } |
| |
| public Object getIteratorProvider() { |
| Iterator<? extends T> iterator = getInnerIterator(); |
| if (iterator instanceof IRepeatableIterator<?>) |
| return ((IRepeatableIterator<?>) iterator).getIteratorProvider(); |
| return this; |
| } |
| |
| protected boolean isMatch(T val) { |
| return elementClass.isInstance(val); |
| } |
| |
| /** |
| * Checks if the expression will make repeated requests for the 'everything' iterator. |
| * @return <code>true</code> if repeated requests will be made, <code>false</code> if not. |
| */ |
| private static boolean needsRepeadedAccessToEverything(Expression expression) { |
| return expression.countAccessToEverything() > 1; |
| } |
| } |