ElementComparator.java

/*=============================================================================#
 # Copyright (c) 2013-2016 Stephan Wahlbrink (WalWare.de) 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:
 #     Stephan Wahlbrink - initial API and implementation
 #=============================================================================*/

package de.walware.ecommons.ltk.core.util;

import java.util.Comparator;

import com.ibm.icu.text.Collator;

import de.walware.ecommons.ltk.LTKUtil;
import de.walware.ecommons.ltk.core.model.IModelElement;
import de.walware.ecommons.ltk.core.model.ISourceElement;
import de.walware.ecommons.ltk.core.model.ISourceUnit;


public class ElementComparator implements Comparator<IModelElement> {
	
	
	private final Collator unitComparator;
	private final Collator elementComparator;
	
	
	public ElementComparator() {
		this(Collator.getInstance());
	}
	
	public ElementComparator(final Collator elementComparator) {
		this.unitComparator= Collator.getInstance();
		this.elementComparator= elementComparator;
	}
	
	
	@Override
	public int compare(final IModelElement e1, final IModelElement e2) {
		final ISourceUnit u1 = LTKUtil.getSourceUnit(e1);
		final ISourceUnit u2 = LTKUtil.getSourceUnit(e2);
		int result = 0;
		if (u1 != null && u2 != null) {
			if (u1 != u2) {
				result = this.unitComparator.compare(u1.getId(), u2.getId());
			}
			if (result != 0) {
				return result;
			}
			if (e1 instanceof ISourceElement) {
				if (e2 instanceof ISourceElement) {
					return compareSourceElementsInUnit((ISourceElement) e1, (ISourceElement) e2);
				}
				return -1000000;
			}
			else if (e2 instanceof ISourceElement) { // && !(e1 instanceof ISourceUnit)
				return 1000000;
			}
			else {
				return this.elementComparator.compare(e1.getId(), e2.getId());
			}
		}
		if (u1 == null && u2 != null) {
			return Integer.MAX_VALUE;
		}
		if (u2 == null && u1 != null) {
			return Integer.MIN_VALUE;
		}
		return 0;
	}
	
	protected int compareSourceElementsInUnit(final ISourceElement e1, final ISourceElement e2) {
		return (e1.getSourceRange().getOffset() - 
				e2.getSourceRange().getOffset());
	}
	
}