Copyright (c) 2005, 2013 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2005, 2013 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.jdt.internal.corext.refactoring.util;

import java.util.HashSet;
import java.util.Iterator;
import java.util.List;

import org.eclipse.jdt.core.dom.ASTNode;
import org.eclipse.jdt.core.dom.ChildListPropertyDescriptor;
import org.eclipse.jdt.core.dom.StructuralPropertyDescriptor;
import org.eclipse.jdt.core.dom.rewrite.TargetSourceRangeComputer;

import org.eclipse.jdt.internal.corext.dom.ASTNodes;

A source range computer that uses the shortest possible source range for a given set of nodes.
 For other nodes, the default extended source range from TargetSourceRangeComputer.computeSourceRange(ASTNode) is used. 

For nodes inside "tight" nodes, the source range is the extended source range, unless this would
violate the no-overlapping condition from the superclass.
Since:
3.2/**
 * A source range computer that uses the shortest possible source range for a given set of nodes.
 * <p>
 * For other nodes, the default extended source range from
 * {@link TargetSourceRangeComputer#computeSourceRange(ASTNode)} is used.
 * <p>
 * For nodes inside "tight" nodes, the source range is the extended source range, unless this would
 * violate the no-overlapping condition from the superclass.
 * 
 * @since 3.2
 */
public class TightSourceRangeComputer extends TargetSourceRangeComputer {
	private HashSet<ASTNode> fTightSourceRangeNodes= new HashSet<>();

	
Add the given node to the set of "tight" nodes.
Params:
reference – a node
Since:
3.2/**
	 * Add the given node to the set of "tight" nodes.
	 * 
	 * @param reference a node
	 * @since 3.2
	 */
	public void addTightSourceNode(ASTNode reference) {
		fTightSourceRangeNodes.add(reference);

	    List<StructuralPropertyDescriptor> properties= reference.structuralPropertiesForType();
	    for (Iterator<StructuralPropertyDescriptor> iterator= properties.iterator(); iterator.hasNext();) {
	        StructuralPropertyDescriptor descriptor= iterator.next();
	        if (descriptor.isChildProperty()) {
	        	ASTNode child= (ASTNode)reference.getStructuralProperty(descriptor);
	        	if (child != null && isExtending(child, reference)) {
	        		addTightSourceNode(child);
	        	}
	        } else if (descriptor.isChildListProperty()) {
	        	List<? extends ASTNode> children= ASTNodes.getChildListProperty(reference, (ChildListPropertyDescriptor) descriptor);
	        	for (Iterator<? extends ASTNode> iterator2= children.iterator(); iterator2.hasNext();) {
	                ASTNode child= iterator2.next();
	                if (isExtending(child, reference)) {
		        		addTightSourceNode(child);
		        	}
                }
	        }
        }
    }

	@Override
	public SourceRange computeSourceRange(ASTNode node) {
		if (fTightSourceRangeNodes.contains(node)) {
			return new TargetSourceRangeComputer.SourceRange(node.getStartPosition(), node.getLength());
		} else {
			return super.computeSourceRange(node); // see bug 85850
		}
	}

	private boolean isExtending(ASTNode child, ASTNode parent) {
	    SourceRange extendedRange= super.computeSourceRange(child);

	    int parentStart= parent.getStartPosition();
		int extendedStart= extendedRange.getStartPosition();
		if (parentStart > extendedStart)
			return true;

		int parentEnd= parentStart + parent.getLength();
		int extendedEnd= extendedStart + extendedRange.getLength();
		if (parentEnd < extendedEnd)
			return true;

	    return false;
    }
}