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package sun.jvm.hotspot.gc.shared;

import java.util.*;

import sun.jvm.hotspot.debugger.*;
import sun.jvm.hotspot.runtime.*;
import sun.jvm.hotspot.types.*;
import sun.jvm.hotspot.utilities.Observable;
import sun.jvm.hotspot.utilities.Observer;

A space that supports compaction operations. This is usually, but not necessarily, a space that is normally contiguous. But, for example, a free-list-based space whose normal collection is a mark-sweep without compaction could still support compaction in full GC's.
/** A space that supports compaction operations. This is usually, but not necessarily, a space that is normally contiguous. But, for example, a free-list-based space whose normal collection is a mark-sweep without compaction could still support compaction in full GC's. */
public abstract class CompactibleSpace extends Space { private static AddressField compactionTopField; 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("CompactibleSpace"); compactionTopField = type.getAddressField("_compaction_top"); } public CompactibleSpace(Address addr) { super(addr); }
May be used temporarily during a compaction phase.
/** May be used temporarily during a compaction phase. */
public Address compactionTop() { return compactionTopField.getValue(addr); } }