methodreturnvaluestreamfactory.java

一个查找java程序里bug的程序的源代码,该程序本身也是java写的,对提高java编程水平很有用

/*
 * FindBugs - Find bugs in Java programs
 * Copyright (C) 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.detect;

import java.util.*;

import edu.umd.cs.findbugs.ba.Hierarchy;
import edu.umd.cs.findbugs.ba.Location;
import edu.umd.cs.findbugs.ba.RepositoryLookupFailureCallback;
import org.apache.bcel.Constants;
import org.apache.bcel.generic.*;

/**
 * StreamFactory for streams that are created as the result
 * of calling a method on an object.
 */
public class MethodReturnValueStreamFactory implements StreamFactory {
	private static final BitSet invokeOpcodeSet = new BitSet();

	static {
		invokeOpcodeSet.set(Constants.INVOKEINTERFACE);
		invokeOpcodeSet.set(Constants.INVOKESPECIAL);
		invokeOpcodeSet.set(Constants.INVOKESTATIC);
		invokeOpcodeSet.set(Constants.INVOKEVIRTUAL);
	}

	private ObjectType baseClassType;
	private String methodName;
	private String methodSig;
	private boolean isUninteresting;
	private String bugType;

	/**
	 * Constructor.
	 * The Streams created will be marked as uninteresting.
	 *
	 * @param baseClass  base class through which the method will be
	 *                   called (we check instances of the base class and all subtypes)
	 * @param methodName name of the method called
	 * @param methodSig  signature of the method called
	 */
	public MethodReturnValueStreamFactory(String baseClass, String methodName, String methodSig) {
		this.baseClassType = new ObjectType(baseClass);
		this.methodName = methodName;
		this.methodSig = methodSig;
		this.isUninteresting = true;
	}

	/**
	 * Constructor.
	 * The Streams created will be marked as interesting.
	 *
	 * @param baseClass  base class through which the method will be
	 *                   called (we check instances of the base class and all subtypes)
	 * @param methodName name of the method called
	 * @param methodSig  signature of the method called
	 * @param bugType    the bug type that should be reported if
	 *                   the stream is not closed on all paths out of the method
	 */
	public MethodReturnValueStreamFactory(String baseClass, String methodName, String methodSig,
	                                      String bugType) {
		this.baseClassType = new ObjectType(baseClass);
		this.methodName = methodName;
		this.methodSig = methodSig;
		this.isUninteresting = false;
		this.bugType = bugType;
	}

	public Stream createStream(Location location, ObjectType type, ConstantPoolGen cpg,
	                           RepositoryLookupFailureCallback lookupFailureCallback) {

		try {
			Instruction ins = location.getHandle().getInstruction();

			// For now, just support instance methods
			short opcode = ins.getOpcode();
			if (!invokeOpcodeSet.get(opcode))
				return null;

			// Is invoked class a subtype of the base class we want
			// FIXME: should test be different for INVOKESPECIAL and INVOKESTATIC?
			InvokeInstruction inv = (InvokeInstruction) ins;
			ReferenceType classType = inv.getReferenceType(cpg);
			if (!Hierarchy.isSubtype(classType, baseClassType))
				return null;

			// See if method name and signature match
			String methodName = inv.getMethodName(cpg);
			String methodSig = inv.getSignature(cpg);
			if (!this.methodName.equals(methodName) || !this.methodSig.equals(methodSig))
				return null;

			String streamClass = type.getClassName();
			Stream result = new Stream(location, streamClass, streamClass)
			        .setIgnoreImplicitExceptions(true)
			        .setIsOpenOnCreation(true);
			if (!isUninteresting)
				result.setInteresting(bugType);
			return result;
		} catch (ClassNotFoundException e) {
			lookupFailureCallback.reportMissingClass(e);
		}

		return null;
	}
}

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