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- /*
- * 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.
- */
-
- /* $Id$ */
-
- package org.apache.fop.layoutmgr;
-
- import java.util.ArrayList;
- import java.util.Iterator;
- import java.util.List;
- import java.util.ListIterator;
-
- import org.apache.fop.util.ListUtil;
-
- /**
- * Represents a list of {@link KnuthElement Knuth elements}.
- */
- public abstract class KnuthSequence extends ArrayList {
-
- //TODO: do not extend ArrayList
-
- /**
- * Creates a new and empty list.
- */
- public KnuthSequence() {
- super();
- }
-
- /**
- * Creates a new list from an existing list.
- * @param list The list from which to create the new list.
- */
- public KnuthSequence(List list) {
- super(list);
- }
-
- /**
- * Marks the start of the sequence.
- */
- public void startSequence() {
- }
-
- /**
- * Finalizes a Knuth sequence.
- * @return a finalized sequence.
- */
- public abstract KnuthSequence endSequence();
-
- /**
- * Can sequence be appended to this sequence?
- * @param sequence The sequence that may be appended.
- * @return whether the sequence can be appended to this sequence.
- */
- public abstract boolean canAppendSequence(KnuthSequence sequence);
-
- /**
- * Append sequence to this sequence if it can be appended.
- * @param sequence The sequence that is to be appended.
- * @param keepTogether Whether the two sequences must be kept together.
- * @param breakElement The BreakElement that may be inserted between the two sequences.
- * @return whether the sequence was succesfully appended to this sequence.
- */
- public abstract boolean appendSequence(KnuthSequence sequence, boolean keepTogether,
- BreakElement breakElement);
-
- /**
- * Append sequence to this sequence if it can be appended.
- * @param sequence The sequence that is to be appended.
- * @return whether the sequence was succesfully appended to this sequence.
- */
- public abstract boolean appendSequence(KnuthSequence sequence);
-
- /**
- * Append sequence to this sequence if it can be appended.
- * If that is not possible, close this sequence.
- * @param sequence The sequence that is to be appended.
- * @return whether the sequence was succesfully appended to this sequence.
- */
- public boolean appendSequenceOrClose(KnuthSequence sequence) {
- if (!appendSequence(sequence)) {
- endSequence();
- return false;
- } else {
- return true;
- }
- }
-
- /**
- * Append sequence to this sequence if it can be appended.
- * If that is not possible, close this sequence.
- * @param sequence The sequence that is to be appended.
- * @param keepTogether Whether the two sequences must be kept together.
- * @param breakElement The BreakElement that may be inserted between the two sequences.
- * @return whether the sequence was succesfully appended to this sequence.
- */
- public boolean appendSequenceOrClose(KnuthSequence sequence, boolean keepTogether,
- BreakElement breakElement) {
- if (!appendSequence(sequence, keepTogether, breakElement)) {
- endSequence();
- return false;
- } else {
- return true;
- }
- }
-
- /**
- * Wrap the Positions of the elements of this sequence in a Position for LayoutManager lm.
- * @param lm The LayoutManager for the Positions that will be created.
- */
- public void wrapPositions(LayoutManager lm) {
- ListIterator listIter = listIterator();
- ListElement element;
- while (listIter.hasNext()) {
- element = (ListElement) listIter.next();
- element.setPosition(
- lm.notifyPos(new NonLeafPosition(lm, element.getPosition())));
- }
- }
-
- /**
- * @return the last element of this sequence.
- */
- public ListElement getLast() {
- return (isEmpty()
- ? null
- : (ListElement) ListUtil.getLast(this));
- }
-
- /**
- * Remove the last element of this sequence.
- * @return the removed element.
- */
- public ListElement removeLast() {
- return (isEmpty()
- ? null
- : (ListElement) ListUtil.removeLast(this));
- }
-
- /**
- * @param index The index of the element to be returned
- * @return the element at index index.
- */
- public ListElement getElement(int index) {
- return (index >= size() || index < 0)
- ? null
- : (ListElement) get(index);
- }
-
- /**
- * Returns the position index of the first box in this sequence, starting at the given
- * index. If {@code startIndex} is outside the bounds of this sequence, it is
- * returned.
- *
- * @param startIndex the index from which to start the lookup
- * @return the index of the next box element, {@link #size()} if there is no such
- * element, {@code startIndex} if {@code (startIndex < 0 || startIndex >= size())}
- */
- protected int getFirstBoxIndex(int startIndex) {
- if (startIndex < 0 || startIndex >= size()) {
- return startIndex;
- } else {
- int boxIndex = startIndex;
- @SuppressWarnings("unchecked")
- Iterator<ListElement> iter = listIterator(startIndex);
- while (iter.hasNext() && !iter.next().isBox()) {
- boxIndex++;
- }
- return boxIndex;
- }
- }
-
- /**
- * Is this an inline or a block sequence?
- * @return true if this is an inline sequence
- */
- public abstract boolean isInlineSequence();
-
- /** {@inheritDoc} */
- public String toString() {
- return "<KnuthSequence " + super.toString() + ">";
- }
-
- }
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