/*

 * Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.

 * 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.

 *

 * 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

package sun.jvm.hotspot.gc.shared;

import java.io.*;

import java.util.*;

import sun.jvm.hotspot.debugger.*;

import sun.jvm.hotspot.memory.*;

import sun.jvm.hotspot.runtime.*;

import sun.jvm.hotspot.types.*;

/** <P> The (supported) Generation hierarchy currently looks like this: </P>

    <ul>

    <li> Generation

      <ul>

      <li> CardGeneration

        <ul>

        <li> TenuredGeneration

        </ul>

      <li> DefNewGeneration

      </ul>

    </ul>

*/

public abstract class Generation extends VMObject {

  private static long          reservedFieldOffset;

  private static long          virtualSpaceFieldOffset;

  protected static final int  K = 1024;

  // Fields for class StatRecord

  private static Field         statRecordField;

  private static CIntegerField invocationField;

  // constants from Name enum

  private static int NAME_DEF_NEW;

  private static int NAME_PAR_NEW;

  private static int NAME_MARK_SWEEP_COMPACT;

  private static int NAME_CONCURRENT_MARK_SWEEP;

  private static int NAME_OTHER;

  static {

    VM.registerVMInitializedObserver(new Observer() {

        public void update(Observable o, Object data) {

          initialize(VM.getVM().getTypeDataBase());

        }

      });

  }

  private static synchronized void initialize(TypeDataBase db) {

    Type type = db.lookupType("Generation");

    reservedFieldOffset     = type.getField("_reserved").getOffset();

    virtualSpaceFieldOffset = type.getField("_virtual_space").getOffset();

    // StatRecord

    statRecordField         = type.getField("_stat_record");

    type                    = db.lookupType("Generation::StatRecord");

    invocationField         = type.getCIntegerField("invocations");

    // constants from Generation::Name

    NAME_DEF_NEW = db.lookupIntConstant("Generation::DefNew").intValue();

    NAME_PAR_NEW = db.lookupIntConstant("Generation::ParNew").intValue();

    NAME_MARK_SWEEP_COMPACT = db.lookupIntConstant("Generation::MarkSweepCompact").intValue();

    NAME_CONCURRENT_MARK_SWEEP = db.lookupIntConstant("Generation::ConcurrentMarkSweep").intValue();

    NAME_OTHER = db.lookupIntConstant("Generation::Other").intValue();

  }

  public Generation(Address addr) {

    super(addr);

  }

  public static class Name {

    public static final Name DEF_NEW = new Name("DefNew");

    public static final Name PAR_NEW = new Name("ParNew");

    public static final Name MARK_SWEEP_COMPACT = new Name("MarkSweepCompact");

    public static final Name CONCURRENT_MARK_SWEEP = new Name("ConcurrentMarkSweep");

    public static final Name OTHER = new Name("Other");

    private Name(String value) {

      this.value = value;

    }

    private String value;

    public String toString() {

      return value;

    }

  }

  public Generation.Name kind() {

    return Generation.Name.OTHER;

  }

  static Generation.Name nameForEnum(int value) {

     if (value == NAME_DEF_NEW) {

        return Name.DEF_NEW;

     } else if (value == NAME_PAR_NEW) {

        return Name.PAR_NEW;

     } else if (value == NAME_MARK_SWEEP_COMPACT) {

        return Name.MARK_SWEEP_COMPACT;

     } else if (value == NAME_CONCURRENT_MARK_SWEEP) {

        return Name.CONCURRENT_MARK_SWEEP;

     } else if (value == NAME_OTHER) {

        return Name.OTHER;

     } else {

        throw new RuntimeException("should not reach here");

     }

  }

  public int invocations() {

    return getStatRecord().getInvocations();

  }

  /** The maximum number of object bytes the generation can currently

      hold. */

  public abstract long capacity();

  /** The number of used bytes in the gen. */

  public abstract long used();

  /** The number of free bytes in the gen. */

  public abstract long free();

  /** The largest number of contiguous free words in the generation,

      including expansion. (VM's version assumes it is called at a

      safepoint.)  */

  public abstract long contiguousAvailable();

  public MemRegion reserved() {

    return new MemRegion(addr.addOffsetTo(reservedFieldOffset));

  }

  /** Returns a region guaranteed to contain all the objects in the

      generation. */

  public MemRegion usedRegion() {

    return reserved();

  }

  /* Returns "TRUE" iff "p" points into an allocated object in the

     generation. */

  public boolean isIn(Address p) {

    GenerationIsInClosure blk = new GenerationIsInClosure(p);

    spaceIterate(blk);

    return (blk.space() != null);

  }

  /** Returns "TRUE" iff "p" points into the reserved area of the

     generation. */

  public boolean isInReserved(Address p) {

    return reserved().contains(p);

  }

  protected VirtualSpace virtualSpace() {

    return (VirtualSpace) VMObjectFactory.newObject(VirtualSpace.class, addr.addOffsetTo(virtualSpaceFieldOffset));

  }

  public abstract String name();

  /** Equivalent to spaceIterate(blk, false) */

  public void spaceIterate(SpaceClosure blk) {

    spaceIterate(blk, false);

  }

  /** Iteration - do not use for time critical operations */

  public abstract void spaceIterate(SpaceClosure blk, boolean usedOnly);

  public void print() { printOn(System.out); }

  public abstract void printOn(PrintStream tty);

  public static class StatRecord extends VMObject {

    public StatRecord(Address addr) {

      super(addr);

    }

    public int getInvocations() {

      return (int) invocationField.getValue(addr);

    }

  }

  private StatRecord getStatRecord() {

    return (StatRecord) VMObjectFactory.newObject(Generation.StatRecord.class, addr.addOffsetTo(statRecordField.getOffset()));

  }

}