Mercurial > hg > truffle
view graal/com.oracle.max.base/src/com/sun/max/collect/FilterIterator.java @ 3733:e233f5660da4
Added Java files from Maxine project.
author | Thomas Wuerthinger <thomas.wuerthinger@oracle.com> |
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date | Sat, 17 Dec 2011 19:59:18 +0100 |
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/* * Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package com.sun.max.collect; import java.util.*; import com.sun.max.util.*; /** * Filters the elements returned by a given iterator with a given predicate. */ public class FilterIterator<T> implements Iterator<T> { private final Iterator<? extends T> iterator; private final Predicate<T> predicate; private T next; private boolean advanced; public FilterIterator(Iterator<? extends T> iterator, Predicate<T> predicate) { this.iterator = iterator; this.predicate = predicate; } public boolean hasNext() { if (advanced) { return true; } return advance(); } public T next() { if (!advanced) { if (!advance()) { throw new NoSuchElementException(); } } advanced = false; return next; } public void remove() { if (advanced) { throw new IllegalStateException("remove() cannot be called"); } iterator.remove(); } private boolean advance() { while (iterator.hasNext()) { final T n = iterator.next(); if (predicate.evaluate(n)) { next = n; advanced = true; return true; } } return false; } }