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- /*
- * Copyright 1999-2005 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 org.apache.fop.fo.FObj;
- import org.apache.fop.fo.FONode;
- import org.apache.fop.area.Area;
- import org.apache.fop.area.Resolvable;
- import org.apache.fop.area.PageViewport;
- import org.apache.fop.fo.Constants;
- import org.apache.fop.fo.flow.RetrieveMarker;
- import org.apache.fop.fo.flow.Marker;
-
- import org.apache.commons.logging.Log;
- import org.apache.commons.logging.LogFactory;
-
- import java.util.LinkedList;
- import java.util.List;
- import java.util.ArrayList;
- import java.util.ListIterator;
- import java.util.Map;
-
- /**
- * The base class for all LayoutManagers.
- */
- public abstract class AbstractLayoutManager implements LayoutManager, Constants {
- protected LayoutManager parentLM = null;
- protected List childLMs = null;
- protected ListIterator fobjIter = null;
- protected Map markers = null;
-
- /** True if this LayoutManager has handled all of its content. */
- private boolean bFinished = false;
- protected boolean bInited = false;
-
- /**
- * Used during addAreas(): signals that a BreakPoss is not generating areas
- * and therefore doesn't add IDs and markers to the current page.
- * @see org.apache.fop.layoutmgr.AbstractLayoutManager#isBogus
- */
- protected boolean bBogus = false;
-
- /** child LM and child LM iterator during getNextBreakPoss phase */
- protected LayoutManager curChildLM = null;
- protected ListIterator childLMiter = null;
-
- /**
- * logging instance
- */
- protected static Log log = LogFactory.getLog(LayoutManager.class);
-
- /**
- * Abstract layout manager.
- */
- public AbstractLayoutManager() {
- }
-
- /**
- * Abstract layout manager.
- *
- * @param fo the formatting object for this layout manager
- */
- public AbstractLayoutManager(FObj fo) {
- if (fo == null) {
- throw new IllegalStateException("Null formatting object found.");
- }
- setFObj(fo);
- }
-
- /**
- * Set the FO object for this layout manager
- *
- * @param fo the formatting object for this layout manager
- */
- public void setFObj(FObj fo) {
- markers = fo.getMarkers();
- fobjIter = fo.getChildNodes();
- childLMiter = new LMiter(this);
- }
-
- /**
- * This method provides a hook for a LayoutManager to initialize traits
- * for the areas it will create, based on Properties set on its FO.
- */
- public void initialize() {
- if (bInited == false) {
- initProperties();
- bInited = true;
- }
- }
-
- /**
- * This method is called by initialize() to set any method variables
- * based on Properties set on its FO.
- */
- protected void initProperties() {
- }
-
- public void setParent(LayoutManager lm) {
- this.parentLM = lm;
- }
-
- public LayoutManager getParent() {
- return this.parentLM;
- }
-
- // /**
- // * Ask the parent LayoutManager to add the current (full) area to the
- // * appropriate parent area.
- // * @param bFinished If true, this area is finished, either because it's
- // * completely full or because there is no more content to put in it.
- // * If false, we are in the middle of this area. This can happen,
- // * for example, if we find floats in a line. We stop the current area,
- // * and add it (temporarily) to its parent so that we can see if there
- // * is enough space to place the float(s) anchored in the line.
- // */
- // protected void flush(Area area, boolean bFinished) {
- // if (area != null) {
- // // area.setFinished(true);
- // parentLM.addChildArea(area, bFinished); // ????
- // if (bFinished) {
- // setCurrentArea(null);
- // }
- // }
- // }
-
- /**
- * Return an Area which can contain the passed childArea. The childArea
- * may not yet have any content, but it has essential traits set.
- * In general, if the LayoutManager already has an Area it simply returns
- * it. Otherwise, it makes a new Area of the appropriate class.
- * It gets a parent area for its area by calling its parent LM.
- * Finally, based on the dimensions of the parent area, it initializes
- * its own area. This includes setting the content IPD and the maximum
- * BPD.
- */
-
-
- /** @see org.apache.fop.layoutmgr.LayoutManager#generatesInlineAreas() */
- public boolean generatesInlineAreas() {
- return false;
- }
-
- /** @see org.apache.fop.layoutmgr.LayoutManager#isBogus() */
- public boolean isBogus() {
- if (getParent().isBogus()) {
- return true;
- } else {
- return bBogus;
- }
- }
-
- /**
- * Add a child area to the current area. If this causes the maximum
- * dimension of the current area to be exceeded, the parent LM is called
- * to add it.
- */
-
- /**
- * Return currently active child LayoutManager or null if
- * all children have finished layout.
- * Note: child must implement LayoutManager! If it doesn't, skip it
- * and print a warning.
- */
- protected LayoutManager getChildLM() {
- if (curChildLM != null && !curChildLM.isFinished()) {
- return curChildLM;
- }
- while (childLMiter.hasNext()) {
- curChildLM = (LayoutManager) childLMiter.next();
- return curChildLM;
- }
- return null;
- }
-
- protected boolean hasMoreLM(LayoutManager prevLM) {
- // prevLM should = curChildLM
- if (prevLM != curChildLM) {
- //log.debug("AbstractLayoutManager.peekNextLM: " +
- // "passed LM is not current child LM!");
- return false;
- }
- return !childLMiter.hasNext();
- }
-
-
- /**
- * Reset the layoutmanager "iterator" so that it will start
- * with the passed Position's generating LM
- * on the next call to getChildLM.
- * @param pos a Position returned by a child layout manager
- * representing a potential break decision.
- * If pos is null, then back up to the first child LM.
- */
- protected void reset(org.apache.fop.layoutmgr.Position pos) {
- //if (lm == null) return;
- LayoutManager lm = (pos != null) ? pos.getLM() : null;
- if (curChildLM != lm) {
- // ASSERT curChildLM == (LayoutManager)childLMiter.previous()
- if (childLMiter.hasPrevious() && curChildLM
- != (LayoutManager) childLMiter.previous()) {
- //log.error("LMiter problem!");
- }
- while (curChildLM != lm && childLMiter.hasPrevious()) {
- curChildLM.resetPosition(null);
- curChildLM = (LayoutManager) childLMiter.previous();
- }
- // Otherwise next returns same object
- childLMiter.next();
- }
- if (curChildLM != null) {
- curChildLM.resetPosition(pos);
- }
- if (isFinished()) {
- setFinished(false);
- }
- }
-
- public void resetPosition(Position resetPos) {
- // if (resetPos == null) {
- // reset(null);
- // }
- }
-
- /**
- * Tell whether this LayoutManager has handled all of its content.
- * @return True if there are no more break possibilities,
- * ie. the last one returned represents the end of the content.
- */
- public boolean isFinished() {
- return bFinished;
- }
-
- public void setFinished(boolean fin) {
- bFinished = fin;
- }
-
-
- /**
- * Generate and return the next break possibility.
- * Each layout manager must implement this.
- * TODO: should this be abstract or is there some reasonable
- * default implementation?
- */
- public BreakPoss getNextBreakPoss(LayoutContext context) {
- return null;
- }
-
-
- /**
- * Return value indicating whether the next area to be generated could
- * start a new line or flow area.
- * In general, if can't break at the current level, delegate to
- * the first child LM.
- * NOTE: should only be called if the START_AREA flag is set in context,
- * since the previous sibling LM must have returned a BreakPoss which
- * does not allow break-after.
- * QUESTION: in block-stacked areas, does this mean some kind of keep
- * condition, or is it only used for inline-stacked areas?
- * Default implementation always returns true.
- */
- public boolean canBreakBefore(LayoutContext context) {
- return true;
- }
-
-
- /**
- * @see org.apache.fop.layoutmgr.LayoutManager#addAreas(org.apache.fop.layoutmgr.PositionIterator, org.apache.fop.layoutmgr.LayoutContext)
- */
- public void addAreas(PositionIterator posIter, LayoutContext context) {
- }
-
-
- public void getWordChars(StringBuffer sbChars, Position bp1,
- Position bp2) {
- }
-
- /* ---------------------------------------------------------
- * PROVIDE NULL IMPLEMENTATIONS OF METHODS from LayoutManager
- * interface which are declared abstract in AbstractLayoutManager.
- * ---------------------------------------------------------*/
-
- public LinkedList getNextKnuthElements(LayoutContext context,
- int alignment) {
- log.warn("null implementation of getNextKnuthElements() called!");
- setFinished(true);
- return null;
- }
-
- public KnuthElement addALetterSpaceTo(KnuthElement element) {
- log.warn("null implementation of addALetterSpaceTo() called!");
- return element;
- }
-
- public void getWordChars(StringBuffer sbChars, Position pos) {
- log.warn("null implementation of getWordChars() called!");
- }
-
- public void hyphenate(Position pos, HyphContext hc) {
- log.warn("null implementation of hyphenate called!");
- }
-
- public boolean applyChanges(List oldList) {
- log.warn("null implementation of applyChanges() called!");
- return false;
- }
-
- public LinkedList getChangedKnuthElements(List oldList,
- /*int flaggedPenalty,*/
- int alignment) {
- log.warn("null implementation of getChangeKnuthElement() called!");
- return null;
- }
-
- public int getWordSpaceIPD() {
- log.warn("null implementation of getWordSpaceIPD() called!");
- return 0;
- }
-
- /**
- * @see org.apache.fop.layoutmgr.LayoutManager#getParentArea(org.apache.fop.area.Area)
- */
- public Area getParentArea(Area childArea) {
- return null;
- }
-
- public void addChildArea(Area childArea) {
- }
-
- /**
- * Delegate getting the current page viewport to the parent layout manager.
- *
- * @see org.apache.fop.layoutmgr.LayoutManager
- */
- public PageViewport getCurrentPV() {
- return parentLM.getCurrentPV();
- }
-
- /**
- * Delegate resolving the id reference to the parent layout manager.
- *
- * @see org.apache.fop.layoutmgr.LayoutManager
- */
- public PageViewport resolveRefID(String ref) {
- return parentLM.resolveRefID(ref);
- }
-
- /**
- * Add the id to the page.
- * If the id string is not null then add the id to the current page.
- */
- protected void addID(String foID) {
- if (foID != null && foID.length() > 0) {
- addIDToPage(foID);
- }
- }
-
- /**
- * Delegate adding id reference to the parent layout manager.
- *
- * @see org.apache.fop.layoutmgr.LayoutManager
- */
- public void addIDToPage(String id) {
- parentLM.addIDToPage(id);
- }
-
- /**
- * Delegate adding unresolved area to the parent layout manager.
- *
- * @see org.apache.fop.layoutmgr.LayoutManager
- */
- public void addUnresolvedArea(String id, Resolvable res) {
- parentLM.addUnresolvedArea(id, res);
- }
-
- /**
- * Delegate retrieve marker to the parent layout manager.
- *
- * @see org.apache.fop.layoutmgr.LayoutManager
- */
- public Marker retrieveMarker(String name, int pos, int boundary) {
- return parentLM.retrieveMarker(name, pos, boundary);
- }
-
- /**
- * Delegate getLayoutManagerMaker to the parent layout manager.
- *
- * @see org.apache.fop.layoutmgr.LayoutManager
- * @return the LayoutManagerMaker object.
- */
- public LayoutManagerMaker getLayoutManagerMaker() {
- return parentLM.getLayoutManagerMaker();
- }
-
- /**
- * Handles retrieve-marker nodes as they occur.
- * @param foNode FO node to check
- * @return the original foNode or in case of a retrieve-marker the replaced
- * FO node. null if the the replacement results in no nodes to be
- * processed.
- */
- private FONode handleRetrieveMarker(FONode foNode) {
- if (foNode instanceof RetrieveMarker) {
- RetrieveMarker rm = (RetrieveMarker) foNode;
- Marker marker = retrieveMarker(rm.getRetrieveClassName(),
- rm.getRetrievePosition(),
- rm.getRetrieveBoundary());
- if (marker == null) {
- return null;
- }
- rm.bindMarker(marker);
- return rm;
- } else {
- return foNode;
- }
- }
-
- /**
- * Convenience method: preload a number of child LMs
- * @param size the requested number of child LMs
- * @return the list with the preloaded child LMs
- */
- protected List preLoadList(int size) {
- if (fobjIter == null) {
- return null;
- }
- List newLMs = new ArrayList(size);
- while (fobjIter.hasNext() && newLMs.size() < size ) {
- Object theobj = fobjIter.next();
- if (theobj instanceof FONode) {
- FONode foNode = (FONode) theobj;
- foNode = handleRetrieveMarker(foNode);
- if (foNode != null) {
- getLayoutManagerMaker().
- makeLayoutManagers(foNode, newLMs);
- }
- }
- }
- return newLMs;
- }
-
- /**
- * @see org.apache.fop.layoutmgr.LayoutManager#preLoadNext
- */
- public boolean preLoadNext(int pos) {
- List newLMs = preLoadList(pos + 1 - childLMs.size());
- addChildLMs(newLMs);
- return pos < childLMs.size();
- }
-
- /**
- * @see org.apache.fop.layoutmgr.LayoutManager#getChildLMs
- */
- public List getChildLMs() {
- if (childLMs == null) {
- childLMs = new java.util.ArrayList(10);
- }
- return childLMs;
- }
-
- /**
- * @see org.apache.fop.layoutmgr.LayoutManager#addChildLM
- */
- public void addChildLM(LayoutManager lm) {
- if (lm == null) {
- return;
- }
- lm.setParent(this);
- lm.initialize();
- if (childLMs == null) {
- childLMs = new java.util.ArrayList(10);
- }
- childLMs.add(lm);
- log.trace(this.getClass().getName()
- + ": Adding child LM " + lm.getClass().getName());
- }
-
- /**
- * @see org.apache.fop.layoutmgr.LayoutManager#addChildLMs
- */
- public void addChildLMs(List newLMs) {
- if (newLMs == null || newLMs.size() == 0) {
- return;
- }
- ListIterator iter = newLMs.listIterator();
- while (iter.hasNext()) {
- LayoutManager lm = (LayoutManager) iter.next();
- addChildLM(lm);
- }
- }
-
- }
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