/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

/*

 * The Original Code is HAT. The Initial Developer of the

 * Original Code is Bill Foote, with contributions from others

 * at JavaSoft/Sun.

 */

package com.sun.tools.hat.internal.model;

import com.sun.tools.hat.internal.util.Misc;

/**

 *

 * @author      Bill Foote

 */

/**

 * Represents a member of the rootset, that is, one of the objects that

 * the GC starts from when marking reachable objects.

 */

public class Root {

    private long id;            // ID of the JavaThing we refer to

    private long refererId;     // Thread or Class responsible for this, or 0

    private int index = -1;             // Index in Snapshot.roots

    private int type;

    private String description;

    private JavaHeapObject referer = null;

    private StackTrace stackTrace = null;

    // Values for type.  Higher values are more interesting -- see getType().

    // See also getTypeName()

    public final static int INVALID_TYPE = 0;

    public final static int UNKNOWN = 1;

    public final static int SYSTEM_CLASS = 2;

    public final static int NATIVE_LOCAL = 3;

    public final static int NATIVE_STATIC = 4;

    public final static int THREAD_BLOCK = 5;

    public final static int BUSY_MONITOR = 6;

    public final static int JAVA_LOCAL = 7;

    public final static int NATIVE_STACK = 8;

    public final static int JAVA_STATIC = 9;

    public Root(long id, long refererId, int type, String description) {

        this(id, refererId, type, description, null);

    }

    public Root(long id, long refererId, int type, String description,

                StackTrace stackTrace) {

        this.id = id;

        this.refererId = refererId;

        this.type = type;

        this.description = description;

        this.stackTrace = stackTrace;

    }

    public long getId() {

        return id;

    }

    public String getIdString() {

        return Misc.toHex(id);

    }

    public String getDescription() {

        if ("".equals(description)) {

            return getTypeName() + " Reference";

        } else {

            return description;

        }

    }

    /**

     * Return type.  We guarantee that more interesting roots will have

     * a type that is numerically higher.

     */

    public int getType() {

        return type;

    }

    public String getTypeName() {

        switch(type) {

            case INVALID_TYPE:          return "Invalid (?!?)";

            case UNKNOWN:               return "Unknown";

            case SYSTEM_CLASS:          return "System Class";

            case NATIVE_LOCAL:          return "JNI Local";

            case NATIVE_STATIC:         return "JNI Global";

            case THREAD_BLOCK:          return "Thread Block";

            case BUSY_MONITOR:          return "Busy Monitor";

            case JAVA_LOCAL:            return "Java Local";

            case NATIVE_STACK:          return "Native Stack (possibly Java local)";

            case JAVA_STATIC:           return "Java Static";

            default:                    return "??";

        }

    }

    /**

     * Given two Root instances, return the one that is most interesting.

     */

    public Root mostInteresting(Root other) {

        if (other.type > this.type) {

            return other;

        } else {

            return this;

        }

    }

    /**

     * Get the object that's responsible for this root, if there is one.

     * This will be null, a Thread object, or a Class object.

     */

    public JavaHeapObject getReferer() {

        return referer;

    }

    /**

     * @return the stack trace responsible for this root, or null if there

     * is none.

     */

    public StackTrace getStackTrace() {

        return stackTrace;

    }

    /**

     * @return The index of this root in Snapshot.roots

     */

    public int getIndex() {

        return index;

    }

    void resolve(Snapshot ss) {

        if (refererId != 0) {

            referer = ss.findThing(refererId);

        }

        if (stackTrace != null) {

            stackTrace.resolve(ss);

        }

    }

    void setIndex(int i) {

        index = i;

    }

}