| /* |
| * Copyright 1999-2004 The Apache Software Foundation. |
| * |
| * Licensed 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. |
| */ |
| |
| /* $Id$ */ |
| |
| package org.apache.fop.layoutmgr; |
| |
| import java.util.Iterator; |
| import java.util.NoSuchElementException; |
| |
| public abstract class PositionIterator implements Iterator { |
| |
| private Iterator parentIter; |
| private Object nextObj; |
| private LayoutManager childLM; |
| private boolean bHasNext; |
| |
| protected PositionIterator(Iterator pIter) { |
| parentIter = pIter; |
| lookAhead(); |
| //checkNext(); |
| } |
| |
| public LayoutManager getNextChildLM() { |
| // Move to next "segment" of iterator, ie: new childLM |
| if (childLM == null && nextObj != null) { |
| childLM = getLM(nextObj); |
| bHasNext = true; |
| } |
| return childLM; |
| } |
| |
| protected abstract LayoutManager getLM(Object nextObj); |
| |
| protected abstract Position getPos(Object nextObj); |
| |
| private void lookAhead() { |
| if (parentIter.hasNext()) { |
| bHasNext = true; |
| nextObj = parentIter.next(); |
| } else { |
| endIter(); |
| } |
| } |
| |
| protected boolean checkNext() { |
| LayoutManager lm = getLM(nextObj); |
| if (childLM == null) { |
| childLM = lm; |
| } else if (childLM != lm) { |
| // End of this sub-sequence with same child LM |
| bHasNext = false; |
| childLM = null; |
| return false; |
| } |
| return true; |
| } |
| |
| protected void endIter() { |
| bHasNext = false; |
| nextObj = null; |
| childLM = null; |
| } |
| |
| public boolean hasNext() { |
| return (bHasNext && checkNext()); |
| } |
| |
| |
| public Object next() throws NoSuchElementException { |
| if (bHasNext) { |
| Object retObj = getPos(nextObj); |
| lookAhead(); |
| //System.out.println(retObj); |
| return retObj; |
| } else { |
| throw new NoSuchElementException("PosIter"); |
| } |
| } |
| |
| public Object peekNext() { |
| return nextObj; |
| } |
| |
| public void remove() throws UnsupportedOperationException { |
| throw new UnsupportedOperationException("PositionIterator doesn't support remove"); |
| } |
| } |
| |