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comparison truffle/com.oracle.truffle.dsl.processor/src/com/oracle/truffle/dsl/processor/util/Filterator.java @ 21951:9c8c0937da41

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Moving all sources into truffle subdirectory
author Jaroslav Tulach <jaroslav.tulach@oracle.com>
date Wed, 17 Jun 2015 10:58:08 +0200
parents graal/com.oracle.truffle.dsl.processor/src/com/oracle/truffle/dsl/processor/util/Filterator.java@93068303f856
children dc83cc1f94f2
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21950:2a5011c7e641 21951:9c8c0937da41
1 /*
2 * Copyright (c) 2012, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23 package com.oracle.truffle.dsl.processor.util;
24
25 import java.util.*;
26
27 public class Filterator<T> implements Iterator<T> {
28
29 private final Predicate<T> includePredicate;
30 private final Iterator<T> elements;
31
32 private boolean hasCached;
33 private T cached;
34
35 public Filterator(Iterator<T> elements, Predicate<T> includePredicate) {
36 this.elements = elements;
37 this.includePredicate = includePredicate;
38 }
39
40 public boolean hasNext() {
41 if (hasCached) {
42 return true;
43 }
44 nextValue();
45 return hasCached;
46 }
47
48 private void nextValue() {
49 while (!hasCached && elements.hasNext()) {
50 T element = elements.next();
51 if (includePredicate.evaluate(element)) {
52 cached = element;
53 hasCached = true;
54 }
55 }
56 }
57
58 public T next() {
59 T foundCached = getCached();
60 if (foundCached != null) {
61 return foundCached;
62 } else {
63 nextValue();
64 if (!hasCached) {
65 throw new NoSuchElementException();
66 }
67 return getCached();
68 }
69 }
70
71 private T getCached() {
72 if (hasCached) {
73 hasCached = false;
74 T value = cached;
75 cached = null;
76 return value;
77 }
78 return null;
79 }
80
81 @Override
82 public void remove() {
83 elements.remove();
84 }
85
86 }