/*
 * FindBugs - Find Bugs in Java programs
 * Copyright (C) 2003-2007 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.classfile.engine.bcel;

import org.apache.bcel.generic.MethodGen;

import edu.umd.cs.findbugs.ba.AssertionMethods;
import edu.umd.cs.findbugs.ba.CFG;
import edu.umd.cs.findbugs.ba.ClassContext;
import edu.umd.cs.findbugs.ba.DepthFirstSearch;
import edu.umd.cs.findbugs.ba.JavaClassAndMethod;
import edu.umd.cs.findbugs.ba.MethodUnprofitableException;
import edu.umd.cs.findbugs.ba.npe.IsNullValueAnalysis;
import edu.umd.cs.findbugs.ba.npe.IsNullValueDataflow;
import edu.umd.cs.findbugs.ba.vna.ValueNumberDataflow;
import edu.umd.cs.findbugs.classfile.CheckedAnalysisException;
import edu.umd.cs.findbugs.classfile.IAnalysisCache;
import edu.umd.cs.findbugs.classfile.MethodDescriptor;

/**
 * Analysis engine to produce IsNullValueDataflow objects
 * for an analyzed method.
 * 
 * @author David Hovemeyer
 */
public class IsNullValueDataflowFactory extends AnalysisFactory<IsNullValueDataflow> {
	/**
	 * Constructor.
	 */
	public IsNullValueDataflowFactory() {
		super("null value analysis", IsNullValueDataflow.class);
	}

	/* (non-Javadoc)
	 * @see edu.umd.cs.findbugs.classfile.IAnalysisEngine#analyze(edu.umd.cs.findbugs.classfile.IAnalysisCache, java.lang.Object)
	 */
	public IsNullValueDataflow analyze(IAnalysisCache analysisCache, MethodDescriptor descriptor) throws CheckedAnalysisException {
		MethodGen methodGen = getMethodGen(analysisCache, descriptor);
		if (methodGen == null) {
			throw new MethodUnprofitableException(descriptor);
		}
		CFG cfg = getCFG(analysisCache, descriptor);
		ValueNumberDataflow vnaDataflow = getValueNumberDataflow(analysisCache, descriptor);
		DepthFirstSearch dfs = getDepthFirstSearch(analysisCache, descriptor);
		AssertionMethods assertionMethods = getAssertionMethods(analysisCache, descriptor.getClassDescriptor());

		IsNullValueAnalysis invAnalysis = new IsNullValueAnalysis(methodGen, cfg, vnaDataflow, dfs, assertionMethods);

		// Set return value and parameter databases

		invAnalysis.setClassAndMethod(new JavaClassAndMethod(
				getJavaClass(analysisCache, descriptor.getClassDescriptor()),
				getMethod(analysisCache, descriptor)));

		IsNullValueDataflow invDataflow = new IsNullValueDataflow(cfg, invAnalysis);
		invDataflow.execute();
		if (ClassContext.DUMP_DATAFLOW_ANALYSIS) {
			invDataflow.dumpDataflow(invAnalysis);
		}
		return invDataflow;

	}
}
