Package org.eclipse.wst.xml.core.internal.parser.regions

Source Code of org.eclipse.wst.xml.core.internal.parser.regions.XMLContentRegion

/*******************************************************************************
* Copyright (c) 2001, 2005 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
*     IBM Corporation - initial API and implementation
*     Jens Lukowski/Innoopract - initial renaming/restructuring
*    
*******************************************************************************/
package org.eclipse.wst.xml.core.internal.parser.regions;

import org.eclipse.wst.sse.core.internal.provisional.events.RegionChangedEvent;
import org.eclipse.wst.sse.core.internal.provisional.events.StructuredDocumentEvent;
import org.eclipse.wst.sse.core.internal.provisional.text.IStructuredDocumentRegion;
import org.eclipse.wst.sse.core.internal.provisional.text.ITextRegion;
import org.eclipse.wst.sse.core.internal.util.Debug;
import org.eclipse.wst.sse.core.internal.util.Utilities;
import org.eclipse.wst.xml.core.internal.regions.DOMRegionContext;



public class XMLContentRegion implements ITextRegion {
  static private final String fType = DOMRegionContext.XML_CONTENT;
  // length and textLength are always the same for content region
  //private int fTextLength;
  private int fLength;
  private int fStart;


  public XMLContentRegion() {
    super();
  }

  public XMLContentRegion(int start, int length) {
    this();
    fStart = start;
    fLength = length;
  }


  public void adjustLength(int i) {
    fLength += i;

  }

  public void adjustStart(int i) {
    fStart += i;

  }


  public void adjustTextLength(int i) {
    // not supported

  }

  public void equatePositions(ITextRegion region) {
    fStart = region.getStart();
    fLength = region.getLength();
  }

  public int getEnd() {
    return fStart + fLength;
  }

  public int getLength() {
    return fLength;
  }

  public int getStart() {
    return fStart;
  }

  public int getTextEnd() {
    return fStart + fLength;
  }

  public int getTextLength() {
    return fLength;
  }

  public String getType() {
    return fType;
  }

  public String toString() {
    return RegionToStringUtil.toString(this);
  }


  public StructuredDocumentEvent updateRegion(Object requester, IStructuredDocumentRegion parent, String changes, int requestStart, int lengthToReplace) {
    // TODO: this is a pretty lame method, since XML Content can have a
    // much
    // better rule for region update, but this is what previous
    // (unfactored)
    // version had, so I'll carry it over, of now.
    RegionChangedEvent result = null;
    // if the region is an easy type (e.g. attribute value),
    // and the requested changes are all
    // alphanumeric, then make the change here locally.
    // (This can obviously be made more sophisticated as the need arises,
    // but should
    // always follow this pattern.)
    if (Debug.debugStructuredDocument) {
      System.out.println("\t\tContextRegion::updateModel"); //$NON-NLS-1$
      System.out.println("\t\t\tregion type is " + fType); //$NON-NLS-1$
    }
    boolean canHandle = false;
    // note: we'll always handle deletes from these
    // regions ... if its already that region,
    // deleting something from it won't change its
    // type. (remember, the calling program needs
    // to insure we are not called, if not all contained
    // on one region.
    if ((changes == null) || (changes.length() == 0)) {
      // delete case
      // We can not do the quick delete, if
      // if all the text in a region is to be deleted.
      // Or, if the delete starts in the white space region.
      // In these cases, a reparse is needed.
      // Minor note, we use textEnd-start since it always
      // less than or equal to end-start. This might
      // cause us to miss a few cases we could have handled,
      // but will prevent us from trying to handle funning cases
      // involving whitespace.
      if ((fStart >= getTextEnd()) || (Math.abs(lengthToReplace) >= getTextEnd() - getStart())) {
        canHandle = false;
      } else {
        canHandle = true;
      }
    } else {
      if ((RegionUpdateRule.canHandleAsWhiteSpace(this, parent, changes, requestStart, lengthToReplace)) || RegionUpdateRule.canHandleAsLetterOrDigit(this, parent, changes, requestStart, lengthToReplace)) {
        canHandle = true;
      } else {
        canHandle = false;
      }

    }
    if (canHandle) {
      // at this point, we still have the old region. We won't create a
      // new instance, we'll just update the one we have, by changing
      // its end postion,
      // The parent flatnode, upon return, has responsibility
      // for updating sibling regions.
      // and in turn, the structuredDocument itself has responsibility
      // for
      // updating the text store and down stream flatnodes.
      if (Debug.debugStructuredDocument) {
        System.out.println("change handled by region"); //$NON-NLS-1$
      }
      int lengthDifference = Utilities.calculateLengthDifference(changes, lengthToReplace);
      // Note: we adjust both end and text end, because for any change
      // that is in only the trailing whitespace region, we should not
      // do a quick change,
      // so 'canHandle' should have been false for those case.
      fLength += lengthDifference;
      // TO_DO_FUTURE: cache value of canHandleAsWhiteSpace from above
      // If we are handling as whitespace, there is no need to increase
      // the text length, only
      // the total length is changing.
      // don't need for content region
      //      if (!RegionUpdateRule.canHandleAsWhiteSpace(this, changes,
      // fStart, lengthToReplace)) {
      //        fTextLength += lengthDifference;
      //      }
      result = new RegionChangedEvent(parent.getParentDocument(), requester, parent, this, changes, requestStart, lengthToReplace);
    }

    return result;
  }

}
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