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/*
 * 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 org.apache.bcel.Const;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.Instruction;
import org.apache.bcel.generic.ObjectType;

import edu.umd.cs.findbugs.ba.Hierarchy;
import edu.umd.cs.findbugs.ba.Location;
import edu.umd.cs.findbugs.ba.RepositoryLookupFailureCallback;

/**
 * StreamFactory for stream objects loaded from instance fields.
 *
 * @author David Hovemeyer
 */
public class InstanceFieldLoadStreamFactory implements StreamFactory {
    private final String streamBaseClass;

    private String bugPatternType;

    /**
     * Constructor. By default, Streams created by this factory will not be
     * marked as interesting. The setBugPatternType() method should be called to
     * make the factory produce interesting streams.
     *
     * @param streamBaseClass
     *            the base class of the streams produced by the factory
     */
    public InstanceFieldLoadStreamFactory(String streamBaseClass) {
        this.streamBaseClass = streamBaseClass;
    }

    /**
     * Set the bug pattern type reported for unclosed streams loaded from this
     * field. This makes the created streams "interesting".
     *
     * @param bugPatternType
     *            the bug pattern type
     */
    public InstanceFieldLoadStreamFactory setBugPatternType(String bugPatternType) {
        this.bugPatternType = bugPatternType;
        return this;
    }

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

        Instruction ins = location.getHandle().getInstruction();
        if (ins.getOpcode() != Const.GETFIELD) {
            return null;
        }

        String fieldClass = type.getClassName();
        try {
            if (fieldClass.startsWith("[")) {
                return null;
            }
            if (!Hierarchy.isSubtype(fieldClass, streamBaseClass)) {
                return null;
            }

            Stream stream = new Stream(location, fieldClass, streamBaseClass);
            stream.setIsOpenOnCreation(true);
            stream.setOpenLocation(location);
            if (bugPatternType != null) {
                stream.setInteresting(bugPatternType);
            }

            // System.out.println("Instance field stream at " + location);
            return stream;
        } catch (ClassNotFoundException e) {
            lookupFailureCallback.reportMissingClass(e);
            return null;
        }
    }
}