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Java example source code file (G1CollectedHeap.java)

This example Java source code file (G1CollectedHeap.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

address, addressfield, cintegerfield, collectedheapname, g1collectedheap, g1monitoringsupport, heapregionseq, heapregionsetbase, iterator, memregion, object, observer, sharedheap, type, util

The G1CollectedHeap.java Java example source code

/*
 * Copyright (c) 2011, 2012, 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_implementation.g1;

import java.util.Iterator;
import java.util.Observable;
import java.util.Observer;

import sun.jvm.hotspot.debugger.Address;
import sun.jvm.hotspot.gc_interface.CollectedHeapName;
import sun.jvm.hotspot.memory.MemRegion;
import sun.jvm.hotspot.memory.SharedHeap;
import sun.jvm.hotspot.memory.SpaceClosure;
import sun.jvm.hotspot.runtime.VM;
import sun.jvm.hotspot.runtime.VMObjectFactory;
import sun.jvm.hotspot.types.AddressField;
import sun.jvm.hotspot.types.CIntegerField;
import sun.jvm.hotspot.types.Type;
import sun.jvm.hotspot.types.TypeDataBase;

// Mirror class for G1CollectedHeap.

public class G1CollectedHeap extends SharedHeap {
    // HeapRegionSeq _seq;
    static private long hrsFieldOffset;
    // MemRegion _g1_committed;
    static private long g1CommittedFieldOffset;
    // size_t _summary_bytes_used;
    static private CIntegerField summaryBytesUsedField;
    // G1MonitoringSupport* _g1mm;
    static private AddressField g1mmField;
    // MasterOldRegionSet _old_set;
    static private long oldSetFieldOffset;
    // MasterHumongousRegionSet _humongous_set;
    static private long humongousSetFieldOffset;

    static {
        VM.registerVMInitializedObserver(new Observer() {
                public void update(Observable o, Object data) {
                    initialize(VM.getVM().getTypeDataBase());
                }
            });
    }

    static private synchronized void initialize(TypeDataBase db) {
        Type type = db.lookupType("G1CollectedHeap");

        hrsFieldOffset = type.getField("_hrs").getOffset();
        g1CommittedFieldOffset = type.getField("_g1_committed").getOffset();
        summaryBytesUsedField = type.getCIntegerField("_summary_bytes_used");
        g1mmField = type.getAddressField("_g1mm");
        oldSetFieldOffset = type.getField("_old_set").getOffset();
        humongousSetFieldOffset = type.getField("_humongous_set").getOffset();
    }

    public long capacity() {
        Address g1CommittedAddr = addr.addOffsetTo(g1CommittedFieldOffset);
        MemRegion g1Committed = new MemRegion(g1CommittedAddr);
        return g1Committed.byteSize();
    }

    public long used() {
        return summaryBytesUsedField.getValue(addr);
    }

    public long n_regions() {
        return hrs().length();
    }

    private HeapRegionSeq hrs() {
        Address hrsAddr = addr.addOffsetTo(hrsFieldOffset);
        return (HeapRegionSeq) VMObjectFactory.newObject(HeapRegionSeq.class,
                                                         hrsAddr);
    }

    public G1MonitoringSupport g1mm() {
        Address g1mmAddr = g1mmField.getValue(addr);
        return (G1MonitoringSupport) VMObjectFactory.newObject(G1MonitoringSupport.class, g1mmAddr);
    }

    public HeapRegionSetBase oldSet() {
        Address oldSetAddr = addr.addOffsetTo(oldSetFieldOffset);
        return (HeapRegionSetBase) VMObjectFactory.newObject(HeapRegionSetBase.class,
                                                             oldSetAddr);
    }

    public HeapRegionSetBase humongousSet() {
        Address humongousSetAddr = addr.addOffsetTo(humongousSetFieldOffset);
        return (HeapRegionSetBase) VMObjectFactory.newObject(HeapRegionSetBase.class,
                                                             humongousSetAddr);
    }

    private Iterator<HeapRegion> heapRegionIterator() {
        return hrs().heapRegionIterator();
    }

    public void heapRegionIterate(SpaceClosure scl) {
        Iterator<HeapRegion> iter = heapRegionIterator();
        while (iter.hasNext()) {
            HeapRegion hr = iter.next();
            scl.doSpace(hr);
        }
    }

    public CollectedHeapName kind() {
        return CollectedHeapName.G1_COLLECTED_HEAP;
    }

    public G1CollectedHeap(Address addr) {
        super(addr);
    }
}

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