content: /*******************************************************************************
   * Copyright (c) 2000, 2007 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
   *******************************************************************************/
  package org.eclipse.wst.jsdt.internal.corext.dom;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.eclipse.core.runtime.Assert;
  import org.eclipse.jface.text.IRegion;
  import org.eclipse.jface.text.Region;
  import org.eclipse.wst.jsdt.core.dom.ASTNode;
  import org.eclipse.wst.jsdt.core.dom.Expression;
  
  
  /**
  *
  * Provisional API: This class/interface is part of an interim API that is still under development and expected to
  * change significantly before reaching stability. It is being made available at this early stage to solicit feedback
  * from pioneering adopters on the understanding that any code that uses this API will almost certainly be broken
  * (repeatedly) as the API evolves.
  */
  public class SelectionAnalyzer extends GenericVisitor {
  	
  	private Selection fSelection;
  	private boolean fTraverseSelectedNode;
  	private ASTNode fLastCoveringNode;
  	
  	// Selected nodes
  	private List fSelectedNodes;
  	
  	public SelectionAnalyzer(Selection selection, boolean traverseSelectedNode) {
  		super(true);
  		Assert.isNotNull(selection);
  		fSelection= selection;
  		fTraverseSelectedNode= traverseSelectedNode;
  	}
  	
  	public boolean hasSelectedNodes() {
  		return fSelectedNodes != null && !fSelectedNodes.isEmpty();
  	}
  	
  	public ASTNode[] getSelectedNodes() {
  		if (fSelectedNodes == null || fSelectedNodes.isEmpty())
  			return new ASTNode[0];
  		return (ASTNode[]) fSelectedNodes.toArray(new ASTNode[fSelectedNodes.size()]);
  	}
  	
  	public ASTNode getFirstSelectedNode() {
  		if (fSelectedNodes == null || fSelectedNodes.isEmpty())
  			return null;
  		return (ASTNode)fSelectedNodes.get(0);
  	}
  	
  	public ASTNode getLastSelectedNode() {
  		if (fSelectedNodes == null || fSelectedNodes.isEmpty())
  			return null;
  		return (ASTNode)fSelectedNodes.get(fSelectedNodes.size() - 1);
  	}
  	
  	public boolean isExpressionSelected() {
  		if (!hasSelectedNodes())
  			return false;
  		return fSelectedNodes.get(0) instanceof Expression;
  	}
  	
  	public IRegion getSelectedNodeRange() {
  		if (fSelectedNodes == null || fSelectedNodes.isEmpty())
  			return null;
  		ASTNode firstNode= (ASTNode)fSelectedNodes.get(0);
  		ASTNode lastNode= (ASTNode)fSelectedNodes.get(fSelectedNodes.size() - 1);
  		int start= firstNode.getStartPosition();
  		return new Region(start, lastNode.getStartPosition() + lastNode.getLength() - start);
  	}
  	
  	public ASTNode getLastCoveringNode() {
  		return fLastCoveringNode;
  	}
  	
  	protected Selection getSelection() {
  		return fSelection;
  	}
  	
  	//--- node management ---------------------------------------------------------
  	
  	protected boolean visitNode(ASTNode node) {
  		// The selection lies behind the node.
  		if (fSelection.liesOutside(node)) {
  			return false;
  		} else if (fSelection.covers(node)) {
  			if (isFirstNode()) {
  				handleFirstSelectedNode(node);
  			} else {
  				handleNextSelectedNode(node);
  			}
  			return fTraverseSelectedNode;
  		} else if (fSelection.coveredBy(node)) {
  			fLastCoveringNode= node;
  			return true;
  		} else if (fSelection.endsIn(node)) {
  			return handleSelectionEndsIn(node);
  		}
  		// There is a possibility that the user has selected trailing semicolons that don't belong
  		// to the statement. So dive into it to check if sub nodes are fully covered.
  		return true;
  	}
  	
  	protected void reset() {
  		fSelectedNodes= null;
  	}
  	
  	protected void handleFirstSelectedNode(ASTNode node) {
  		fSelectedNodes= new ArrayList(5);
  		fSelectedNodes.add(node);
  	}
  	
  	protected void handleNextSelectedNode(ASTNode node) {
  		if (getFirstSelectedNode().getParent() == node.getParent()) {
  			fSelectedNodes.add(node);
  		}
  	}
  
  	protected boolean handleSelectionEndsIn(ASTNode node) {
  		return false;
  	}
  	
  	protected List internalGetSelectedNodes() {
  		return fSelectedNodes;
  	}
  	
  	private boolean isFirstNode() {
  		return fSelectedNodes == null;
  	}	
  }
  