/*
 * Bytecode Analysis Framework
 * Copyright (C) 2003,2004 University of Maryland
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package edu.umd.cs.findbugs.ba.bcp;

/**
 * Abstract PatternElement subclass for matching single instructions which have
 * a single Variable.
 *
 * @see PatternElement
 */
public abstract class OneVariableInstruction extends SingleInstruction {
	private String varName;

	/**
	 * Constructor.
	 *
	 * @param varName the name of the Variable used in this instruction
	 */
	public OneVariableInstruction(String varName) {
		this.varName = varName;
	}

	/**
	 * Add a variable definition to the given BindingSet, or if
	 * there is an existing definition, make sure it is consistent with
	 * the new definition.
	 *
	 * @param variable   the Variable which should be added or checked for consistency
	 * @param bindingSet the existing set of bindings
	 * @return a MatchResult containing the updated BindingSet (if the variable is consistent with the
	 *         previous bindings), or null if the new variable is inconsistent with
	 *         the previous bindings
	 */
	protected MatchResult addOrCheckDefinition(Variable variable, BindingSet bindingSet) {
		bindingSet = addOrCheckDefinition(varName, variable, bindingSet);
		return bindingSet != null
				? new MatchResult(this, bindingSet)
				: null;
	}

}

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