/*
 * FindBugs - Find bugs in Java programs
 * Copyright (C) 2004 Dave Brosius <dbrosius@users.sourceforge.net>
 * 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.detect;

import java.util.*;

import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.BytecodeScanningDetector;
import edu.umd.cs.findbugs.OpcodeStack;
import edu.umd.cs.findbugs.FieldAnnotation;
import edu.umd.cs.findbugs.visitclass.Constants2;
import org.apache.bcel.classfile.*;
import org.apache.bcel.generic.*;
import org.apache.bcel.Repository;

public class UseObjectEquals extends BytecodeScanningDetector implements Constants2 {
	private BugReporter bugReporter;
	private OpcodeStack stack;

	public UseObjectEquals(BugReporter bugReporter) {
		this.bugReporter = bugReporter;
	}

	public void visit(Method obj) {
		super.visit(obj);
		stack = new OpcodeStack();
	}
	
	public void sawOpcode(int seen) {					
		try {
			if ((seen == INVOKEVIRTUAL) 
			&&   getNameConstantOperand().equals("equals")
			&&   getSigConstantOperand().equals("(Ljava/lang/Object;)Z")) {
			
				if (stack.getStackDepth() > 1) {
					OpcodeStack.Item item = stack.getStackItem(1);
					JavaClass cls = item.getJavaClass();
				
					if (item.isArray()) {
							bugReporter.reportBug(new BugInstance("UOE_BAD_ARRAY_COMPARE", NORMAL_PRIORITY)
					        		.addClassAndMethod(this)
					        		.addSourceLine(this));
					}
					else if ((cls != null) && cls.isFinal()) {
						if (item.getSignature().equals("Ljava/lang/Class;"))
							return;
						String methodClassName = getClassConstantOperand();
						if (methodClassName.equals("java/lang/Object")) {
							bugReporter.reportBug(new BugInstance("UOE_USE_OBJECT_EQUALS", LOW_PRIORITY)
				        		.addClassAndMethod(this)
				        		.addSourceLine(this));	
				        }
				    }
				}
			}
		} catch (ClassNotFoundException cnfe) {
			//cnfe.printStackTrace();
			bugReporter.reportMissingClass(cnfe);
		}
		finally {
			stack.sawOpcode(this, seen);
		}
	}
}

// vim:ts=4

@@ -2194,16 +2194,19 @@
 %0A%09%09%09%09%09%7D%0A
+/*%0A
 %09%09%09%09%09els
@@ -2614,24 +2614,27 @@
 %7D%0A%09%09%09%09    %7D%0A
+*/%0A
 %09%09%09%09%7D%0A%09%09%09%7D%0A%09

Comment out report for UOE_USE_OBJECT_EQUALS pattern. The called class could be changed to be non-final.