| /******************************************************************************* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| *******************************************************************************/ |
| package org.ofbiz.base.util.collections; |
| |
| import java.util.Iterator; |
| import java.util.NoSuchElementException; |
| |
| public abstract class IteratorWrapper<DEST, SRC> implements Iterator<DEST> { |
| private final Iterator<? extends SRC> it; |
| private boolean nextCalled; |
| private DEST lastDest; |
| private SRC lastSrc; |
| |
| protected IteratorWrapper(Iterator<? extends SRC> it) { |
| this.it = it; |
| } |
| |
| public boolean hasNext() { |
| if (nextCalled) return true; |
| if (!it.hasNext()) return false; |
| do { |
| lastSrc = it.next(); |
| DEST nextDest = convert(lastSrc); |
| if (isValid(lastSrc, nextDest)) { |
| nextCalled = true; |
| lastDest = nextDest; |
| return true; |
| } |
| } while (it.hasNext()); |
| return false; |
| } |
| |
| public DEST next() { |
| if (!nextCalled) { |
| if (!hasNext()) throw new NoSuchElementException(); |
| } |
| nextCalled = false; |
| return lastDest; |
| } |
| |
| public void remove() { |
| if (lastSrc != null) { |
| noteRemoval(lastDest, lastSrc); |
| it.remove(); |
| lastDest = null; |
| lastSrc = null; |
| } else { |
| throw new IllegalStateException(); |
| } |
| } |
| |
| protected boolean isValid(SRC src, DEST dest) { |
| return true; |
| } |
| |
| protected abstract void noteRemoval(DEST dest, SRC src); |
| protected abstract DEST convert(SRC src); |
| } |
| |