/*******************************************************************************
 * Copyright (c) 2000, 2004 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.jdt.internal.corext.dom.fragments;

import org.eclipse.jdt.core.dom.ASTNode;

/**
 * An IASTFragment represents 'part' of an AST, but
 * not necessarily a subtree of the AST.  A fragment
 * may simply be an instance of some sort of pattern
 * or formation in an AST.
 * Such "fragments", however, do correspond to a
 * contiguous source code region, and, thus, posses a
 * source start position, and a source length.  Every
 * fragment maps to an ASTNode, although this mapping is
 * not necessarily straightforward, and more than one
 * fragment may map to a given node.
 * 
 * Fragments support abstract operations, which
 * support the notion of 'matching' fragments.
 * One operation determines whether a fragment 'matches'
 * a given fragment.  Another operation finds all
 * sub-fragments (fragments contained within a 
 * parent fragment, including the parent itself)
 * which 'match' another given fragment.
 * 
 */
public interface IASTFragment {
		
	/**
	 * Determines whether <code> other </code>
	 * 'matches' <code> this </code>.
	 * This binary operation should be reflexive,
	 * symmetric, and transitive.
	 * 
	 * That two node match does not imply that their source ranges
	 * are the same, or that they map (via getAssociatedNode()) to the
	 * same node.
	 */
	public boolean matches(IASTFragment other);
	
	/**
	 * Returns (at least some approximation of) a maximal set of
	 * sub-fragments of this fragment which match <code> toMatch </code>
	 */
	public IASTFragment[] getSubFragmentsMatching(IASTFragment toMatch);

	/**
	 * Every fragment maps to a node.
	 * Multiple fragments can map to the same node.
	 * 
	 * @return ASTNode The node to which this fragment maps.
	 */
	public ASTNode getAssociatedNode();
	
	/**
	 * Every fragment has a source start position.
	 * 
	 * @return int		The source start position.
	 */
	public int getStartPosition();
	
	/**
	 * Every fragment has a source length.
	 * 
	 * @return int		The source length.
	 */
	public int getLength();
}
