/*
 * FindBugs - Find bugs in Java programs
 * Copyright (C) 2005 Dave Brosius <dbrosius@users.sourceforge.net>
 * Copyright (C) 2005 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.SortedSet;
import java.util.TreeSet;

import org.apache.bcel.Repository;
import org.apache.bcel.classfile.JavaClass;

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

public class RedundantInterfaces extends PreorderVisitor implements Detector, StatelessDetector {
    private final BugReporter bugReporter;

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

    @Override
    public void visitClassContext(ClassContext classContext) {
        JavaClass obj = classContext.getJavaClass();

        String superClassName = obj.getSuperclassName();
        if ("java.lang.Object".equals(superClassName)) {
            return;
        }

        String[] interfaceNames = obj.getInterfaceNames();
        if ((interfaceNames == null) || (interfaceNames.length == 0)) {
            return;
        }

        try {
            JavaClass superObj = obj.getSuperClass();
            SortedSet<String> redundantInfNames = new TreeSet<String>();

            for (String interfaceName : interfaceNames) {
                if (!"java/io/Serializable".equals(interfaceName)) {
                    JavaClass inf = Repository.lookupClass(interfaceName.replace('/', '.'));
                    if (superObj.instanceOf(inf)) {
                        redundantInfNames.add(inf.getClassName());
                    }
                }
            }

            if (redundantInfNames.size() > 0) {
                BugInstance bug = new BugInstance(this, "RI_REDUNDANT_INTERFACES", LOW_PRIORITY).addClass(obj);
                for (String redundantInfName : redundantInfNames) {
                    bug.addClass(redundantInfName).describe("INTERFACE_TYPE");
                }

                bugReporter.reportBug(bug);
            }

        } catch (ClassNotFoundException cnfe) {
            bugReporter.reportMissingClass(cnfe);
        }
    }

    @Override
    public void report() {
    }
}
