AbstractOverriddenMethod.java

/*
 * fb-contrib - Auxiliary detectors for Java programs
 * Copyright (C) 2005-2017 Dave Brosius
 * 
 * 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 com.mebigfatguy.fbcontrib.detect;

import org.apache.bcel.classfile.Code;
import org.apache.bcel.classfile.JavaClass;
import org.apache.bcel.classfile.Method;

import com.mebigfatguy.fbcontrib.utils.BugType;

import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.Detector;
import edu.umd.cs.findbugs.ba.ClassContext;
import edu.umd.cs.findbugs.visitclass.PreorderVisitor;

/**
 * finds methods that are declared abstract but override concrete methods in a
 * superclass.
 */
public class AbstractOverriddenMethod extends PreorderVisitor implements Detector {
    private BugReporter bugReporter;
    private ClassContext clsContext;
    private JavaClass[] superClasses;

    /**
     * constructs a AOM detector given the reporter to report bugs on
     * 
     * @param bugReporter
     *            the sync of bug reports
     */
    public AbstractOverriddenMethod(BugReporter bugReporter) {
        this.bugReporter = bugReporter;
    }

    /**
     * implements the detector to collect the super classes
     * 
     * @param classContext
     *            the context object for the currently parsed class
     */
    @Override
    public void visitClassContext(ClassContext classContext) {
        try {
            clsContext = classContext;
            JavaClass cls = classContext.getJavaClass();
            if (cls.isInterface())
                return;
            superClasses = cls.getSuperClasses();
            cls.accept(this);
        } catch (ClassNotFoundException cnfe) {
            bugReporter.reportMissingClass(cnfe);
        } finally {
            clsContext = null;
            superClasses = null;
        }
    }

    /**
     * overrides the visitor to find abstract methods that override concrete
     * ones
     * 
     * @param obj
     *            the context object of the currently parsed method
     */
    @Override
    public void visitMethod(Method obj) {
        if (!obj.isAbstract())
            return;

        String methodName = obj.getName();
        String methodSig = obj.getSignature();
        outer: for (JavaClass cls : superClasses) {
            Method[] methods = cls.getMethods();
            for (Method m : methods) {
                if (m.isPrivate() || m.isAbstract())
                    continue;
                if (methodName.equals(m.getName()) && methodSig.equals(m.getSignature())) {
                    BugInstance bug = new BugInstance(this, BugType.AOM_ABSTRACT_OVERRIDDEN_METHOD.name(), NORMAL_PRIORITY).addClass(this).addMethod(this);

                    Code code = obj.getCode();
                    if (code != null)
                        bug.addSourceLineRange(clsContext, this, 0, code.getLength() - 1);
                    bugReporter.reportBug(bug);

                    break outer;
                }
            }
        }
    }

    /**
     * implements the Detector with a noop
     */
    @Override
    public void report() {
        // not used, part of the Detector interface
    }
}