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Diffstat (limited to 'libjava/gnu/classpath/jdwp/VMIdManager.java')
| -rw-r--r-- | libjava/gnu/classpath/jdwp/VMIdManager.java | 435 |
1 files changed, 0 insertions, 435 deletions
diff --git a/libjava/gnu/classpath/jdwp/VMIdManager.java b/libjava/gnu/classpath/jdwp/VMIdManager.java deleted file mode 100644 index f787a8c..0000000 --- a/libjava/gnu/classpath/jdwp/VMIdManager.java +++ /dev/null @@ -1,435 +0,0 @@ -/* VMIdManager.java -- A reference/example implementation of a manager for - JDWP object/reference type IDs - - Copyright (C) 2005, 2006, 2007 Free Software Foundation - -This file is part of GNU Classpath. - -GNU Classpath is free software; you can redistribute it and/or modify -it under the terms of the GNU General Public License as published by -the Free Software Foundation; either version 2, or (at your option) -any later version. - -GNU Classpath 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 for more details. - -You should have received a copy of the GNU General Public License -along with GNU Classpath; see the file COPYING. If not, write to the -Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA -02110-1301 USA. - -Linking this library statically or dynamically with other modules is -making a combined work based on this library. Thus, the terms and -conditions of the GNU General Public License cover the whole -combination. - -As a special exception, the copyright holders of this library give you -permission to link this library with independent modules to produce an -executable, regardless of the license terms of these independent -modules, and to copy and distribute the resulting executable under -terms of your choice, provided that you also meet, for each linked -terms of your choice, provided that you also meet, for each linked -independent module, the terms and conditions of the license of that -module. An independent module is a module which is not derived from -or based on this library. If you modify this library, you may extend -this exception to your version of the library, but you are not -obligated to do so. If you do not wish to do so, delete this -exception statement from your version. */ - - -package gnu.classpath.jdwp; - -import gnu.classpath.jdwp.exception.InvalidClassException; -import gnu.classpath.jdwp.exception.InvalidObjectException; -import gnu.classpath.jdwp.id.*; - -import java.lang.ref.Reference; -import java.lang.ref.ReferenceQueue; -import java.lang.ref.SoftReference; -import java.nio.ByteBuffer; -import java.util.HashMap; -import java.util.Hashtable; - -/** - * This class manages objects and referencetypes that are reported - * to the debugger. All objects and referencetypes reported to the - * debugger should go through this manager. - * - * A brief summary of what an <code>IdManager</code> must provide: - * - * <code> - * public ObjectId getObjectId (Object theObject); - * public ObjectId get (long id); - * public ObjectId readObjectId (ByteBuffer bb); - * public ReferenceTypeId getReferenceTypeId (Class clazz); - * public ReferenceTypeId getReferenceType (long id); - * public ReferenceTypeId readReferenceTypeId (ByteBuffer bb); - * </code> - * - * See the javadoc on these methods later in this file for more - * information on these functions. - * - * <b>NOTE:</b> All IDs handled by the ID manager (all object and reference - * type IDs) are assumed to be of type <code>long</code>. - * - * <b>NOTE:</b> This class does not manage virtual machine-specific types, - * like methods, fields, and frames. These already have unique IDs within - * the virtual machine and do not need further abstraction here. - * - * @author Keith Seitz (keiths@redhat.com) - */ -public class VMIdManager -{ - // This factory generates ids for objects and types that may - // be sent to a debugger. - private static class IdFactory - { - // ID of last object / referencetype - private static Object _idLock = new Object (); - private static Object _ridLock = new Object (); - private static long _lastId = 0; - private static long _lastRid = 0; - - // A list of all ID types - private static HashMap _idList = new HashMap (); - - // Initialize the id list with known types - static - { - // ObjectId and ArrayId are special cases. See newObjectId. - _idList.put (ClassLoaderId.typeClass, ClassLoaderId.class); - _idList.put (ClassObjectId.typeClass, ClassObjectId.class); - _idList.put (StringId.typeClass, StringId.class); - _idList.put (ThreadId.typeClass, ThreadId.class); - _idList.put (ThreadGroupId.typeClass, ThreadGroupId.class); - } - - /** - * Returns a new id for the given object - * - * @param obj SoftReference of the object for which an id is desired - * @returns a suitable object id - */ - public static ObjectId newObjectId (SoftReference obj) - { - ObjectId id = null; - Object object = obj.get (); - - // Special case: arrays - if (object.getClass ().isArray ()) - id = new ArrayId (); - else - { - // Loop through all classes until we hit baseclass - Class myClass; - for (myClass = object.getClass (); myClass != null; - myClass = myClass.getSuperclass ()) - { - Class clz = (Class) _idList.get (myClass); - if (clz != null) - { - try - { - id = (ObjectId) clz.newInstance (); - synchronized (_idLock) - { - id.setId (++_lastId); - } - id.setReference (obj); - return id; - } - catch (InstantiationException ie) - { - // This really should not happen - throw new RuntimeException ("cannot create new ID", ie); - } - catch (IllegalAccessException iae) - { - // This really should not happen - throw new RuntimeException ("illegal access of ID", iae); - } - } - } - - /* getSuperclass returned null and no matching ID type found. - So it must derive from Object. */ - id = new ObjectId (); - } - - synchronized (_idLock) - { - id.setId (++_lastId); - } - id.setReference (obj); - return id; - } - - /** - * Returns a new reference type id for the given class - * - * @param ref SoftReference to the desired type - * @returns a suitable reference type id or null when the - * reference is cleared. - */ - public static ReferenceTypeId newReferenceTypeId (SoftReference ref) - { - ReferenceTypeId id; - Class clazz = (Class) ref.get (); - if (clazz == null) - return null; - - if (clazz.isArray ()) - id = new ArrayReferenceTypeId (); - else if (clazz.isInterface ()) - id = new InterfaceReferenceTypeId (); - else - id = new ClassReferenceTypeId (); - id.setReference (ref); - synchronized (_ridLock) - { - id.setId (++_lastRid); - } - return id; - } - } - - /** - * This class is a SoftReferenceIdentity type that is used by - * the ID manager. - */ - class ReferenceKey extends SoftReference - { - // Hash code of referent - private int _hash; - - /** - * Constructs a new <code>ReferenceKey</code> object - * with the given referent. - * - * <p>This constructor should only be used for object lookups - * by the backend. - * - * @param referent the object to reference - */ - public ReferenceKey (Object referent) - { - super (referent); - _hash = referent.hashCode (); - } - - /** - * Constructs a new <code>ReferenceKey</code> object - * with the given referent and reference queue. - * - * <p>The JDWP back-end stores a <code>ReferenceKey</code> - * with its corresponding <code>JdwpId</code>. This constructor - * is used by the back-end when adding new IDs to be managed. - * - * @param referent the object to reference - * @param queue the queue to which to report garbage collections - */ - public ReferenceKey (Object referent, ReferenceQueue queue) - { - super (referent, queue); - _hash = referent.hashCode (); - } - - /** - * Returns the hash code of the referent. - * This seems hacky, but is required in order to use this class - * as a hash table key. - * - * @returns the hash code of the referent - */ - public int hashCode () - { - return _hash; - } - - /** - * Comparator for keys - * - * This method can be used in two ways: - * - * <ol> - * <li>For table lookups, where we want to compare referents</li> - * <li>For clearing GCd objects, where we want to compare the actual - * key object (not the referent)</li> - * </ol> - */ - public boolean equals (Object obj) - { - if (obj instanceof ReferenceKey) - { - ReferenceKey ref = (ReferenceKey) obj; - - /* First check if the two references are the same. - If they are, that means we must be clearing GCd objects. */ - if (this == obj) - return true; - - return (ref.get () == get ()); - } - - return false; - } - } - - // instance of VMIdManager - private static VMIdManager _idm = new VMIdManager (); - - // A reference queue for our objects - private ReferenceQueue _refQueue; - - // Mapping of objects (ReferenceKey) to IDs (ObjectId) - private Hashtable _oidTable; - - // Mapping of ID numbers (Long) to IDs (ObjectId) - private Hashtable _idTable; - - /* Mapping of class (ReferenceKey) to IDs (ReferenceTypeId) for reference - types. Unlike other types, reference id types are NEVER released. */ - private Hashtable _classTable; - - // Mapping of ID numbers (Long) to reference type IDs (ReferenceTypeId) - private Hashtable _ridTable; - - /** - * Gets the instance of VMIdManager, constructing a new one - * if none currently exists. - */ - public static VMIdManager getDefault () - { - return _idm; - } - - // Constructs a new <code>IdManager</code> - private VMIdManager () - { - _refQueue = new ReferenceQueue (); - _oidTable = new Hashtable (50); - _idTable = new Hashtable (50); - _classTable = new Hashtable (20); - _ridTable = new Hashtable (20); - } - - // Updates the object ID table, removing IDs whose objects have - // been garbage collected. - private void _update () - { - Reference ref; - while ((ref = _refQueue.poll ()) != null) - { - ObjectId id = (ObjectId) _oidTable.get (ref); - _oidTable.remove (ref); - _idTable.remove (new Long (id.getId ())); - } - } - - /** - * Returns an id for the given object, adding it - * if it does not have an id. - * - * @param theObject the object to get an ID/add - * @returns the ID of the object - */ - public ObjectId getObjectId (Object theObject) - { - // Special case: null object. - if (theObject == null) - return new NullObjectId (); - - ReferenceKey ref = new ReferenceKey (theObject, _refQueue); - ObjectId id = (ObjectId) _oidTable.get (ref); - if (id == null) - { - // update the tables -- this is an arbitrary place to put this - _update (); - - // Object not found. Make new id for it - id = IdFactory.newObjectId (ref); - _oidTable.put (ref, id); - _idTable.put (new Long (id.getId ()), id); - } - - return id; - } - - /** - * Returns the <code>JdwpId</code> for a given ID. Unlike - * <code>getId</code>, it throws an exception if the ID is not - * known. - * - * @param id the numerical ID of the desired <code>JdwpId</code> - * @throws InvalidObjectException if the ID is not found - */ - public ObjectId get (long id) - throws InvalidObjectException - { - // Special case: null object id. - if (id == 0) - return new NullObjectId (); - - ObjectId oid = (ObjectId) _idTable.get (new Long (id)); - if (oid == null) - throw new InvalidObjectException (id); - - return oid; - } - - public ObjectId readObjectId (ByteBuffer bb) - throws InvalidObjectException - { - long id = bb.getLong (); - return get (id); - } - - /** - * Gets the reference type id for the given class, creating - * a new one if it does not already have an id - * - * @param clazz the class for which to get an ID - * @returns the ID of the class - */ - public ReferenceTypeId getReferenceTypeId (Class clazz) - { - ReferenceKey ref = new ReferenceKey (clazz); - ReferenceTypeId id = (ReferenceTypeId)_classTable.get (ref); - if (id == null) - { - // Object not found. Make new id for it - id = IdFactory.newReferenceTypeId (ref); - _classTable.put (ref, id); - _ridTable.put (new Long (id.getId ()), id); - } - - return id; - } - - /** - * Returns the <code>ReferenceTypeId</code> for a given ID. Unlike - * <code>getReferenceTypeId</code>, it throws an exception if the ID is not - * known. - * - * @param id the numerical ID of the desired reference type - * @throws InvalidClassException if the ID is not found - */ - public ReferenceTypeId getReferenceType (long id) - throws InvalidClassException - { - ReferenceTypeId rid = (ReferenceTypeId) _ridTable.get (new Long (id)); - if (rid == null) - throw new InvalidClassException (id); - - return rid; - } - - public ReferenceTypeId readReferenceTypeId (ByteBuffer bb) - throws InvalidClassException - { - long id = bb.getLong (); - return getReferenceType (id); - } -} |