MisleadingOverloadModel.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 java.util.HashMap;
import java.util.Map;

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.ba.XFactory;
import edu.umd.cs.findbugs.visitclass.PreorderVisitor;

/**
 * looks for classes that define both static and instance methods with the same name. This 'overloading' is confusing as one method is instance based the other
 * class based, and points to a confusion in implementation.
 */
public class MisleadingOverloadModel extends PreorderVisitor implements Detector {
    enum MethodFoundType {
        Instance, Static, Both
    }

    private final BugReporter bugReporter;

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

    @Override
    public void visitClassContext(ClassContext classContext) {
        JavaClass cls = classContext.getJavaClass();
        String clsName = cls.getClassName();
        Method[] methods = cls.getMethods();
        Map<String, MethodFoundType> declMethods = new HashMap<>(methods.length);
        for (Method m : methods) {
            String methodName = m.getName();
            boolean report;
            MethodFoundType newType;
            if (m.isStatic()) {
                report = declMethods.get(methodName) == MethodFoundType.Instance;
                if (report) {
                    newType = MethodFoundType.Both;
                } else {
                    newType = MethodFoundType.Static;
                }
            } else {
                report = declMethods.get(m.getName()) == MethodFoundType.Static;
                if (report) {
                    newType = MethodFoundType.Both;
                } else {
                    newType = MethodFoundType.Instance;
                }
            }

            declMethods.put(methodName, newType);
            if (report) {
                bugReporter.reportBug(new BugInstance(this, BugType.MOM_MISLEADING_OVERLOAD_MODEL.name(), NORMAL_PRIORITY).addClass(cls)
                        .addMethod(XFactory.createXMethod(clsName, m)).addString(methodName));
            }
        }
    }

    /** implements the visitor to do nothing */
    @Override
    public void report() {
        // required by the interface, but not needed
    }
}