[RFA/JDWP] IdManager, Events

[Keith Seitz <keiths at redhat dot com>]

Hi,

So, after much discussion last week, I'm not sure where I stand in
making any progress at getting this stuff committed.

I've attached the outstanding patches awaiting more review and/or
approval.

Comments/questions/concerns?
Keith

Index: gnu/classpath/jdwp/event/filters/IEventFilter.java
===================================================================
RCS file: gnu/classpath/jdwp/event/filters/IEventFilter.java
diff -N gnu/classpath/jdwp/event/filters/IEventFilter.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ gnu/classpath/jdwp/event/filters/IEventFilter.java	27 Jun 2005 18:05:44 -0000
@@ -0,0 +1,65 @@
+/* IEventFilter.java -- an interface for event filters
+   Copyright (C) 2005 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., 59 Temple Place, Suite 330, Boston, MA
+02111-1307 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.event.filters;
+
+import gnu.classpath.jdwp.event.Event;
+
+/**
+ * An interface for event filters. The debugger registers an event
+ * filter for a given event when it is interested in receiving
+ * notifications about that event from the VM.
+ *
+ * <p>Filters are attached to {@link gnu.classpath.jdwp.event.EventRequest}s
+ * in order to allow the debugger to specify that an event should be sent
+ * only when the filters for the event request all match.
+ *
+ * <p>No filters means "send all notifications".
+ *
+ * @author Keith Seitz  (keiths@redhat.com)
+ */
+public interface IEventFilter
+{
+  /**
+   * Does the given event match the filter?
+   *
+   * @param event  the <code>Event</code> to scrutinize
+   */
+  public boolean matches (Event event);
+}
Index: gnu/classpath/jdwp/event/Event.java
===================================================================
RCS file: gnu/classpath/jdwp/event/Event.java
diff -N gnu/classpath/jdwp/event/Event.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ gnu/classpath/jdwp/event/Event.java	27 Jun 2005 18:05:57 -0000
@@ -0,0 +1,125 @@
+/* Event.java -- a base class for all event types
+   Copyright (C) 2005 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., 59 Temple Place, Suite 330, Boston, MA
+02111-1307 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.event;
+
+import gnu.classpath.jdwp.JdwpConstants;
+import gnu.classpath.jdwp.transport.JdwpCommandPacket;
+import gnu.classpath.jdwp.transport.JdwpPacket;
+
+import java.io.DataOutputStream;
+import java.io.IOException;
+
+/**
+ * This class is a base class for all VM->debugger event
+ * notifications.
+ *
+ * @author Keith Seitz  (keiths@redhat.com)
+ */
+public abstract class Event
+{
+  // The kind of event represented by this event
+  private byte _eventKind;
+
+  /**
+   * Constructs an <code>Event</code> of the given kind
+   *
+   * @param kind  the type of event
+   */
+  public Event (byte kind)
+  {
+    _eventKind = kind;
+  }
+
+  /**
+   * Returns the event type of this event
+   *
+   * @returns  the event kind
+   */
+  public byte getEventKind ()
+  {
+    return _eventKind;
+  }
+
+  /**
+   * Abstract function used by implementing classes to fill in the
+   * event-specific data. Note that request ID is automatically added
+   * by this class (since it appears in all event notifications).
+   *
+   * @param outStream  the stream to which to write data
+   */
+  protected abstract void _writeData (DataOutputStream outStream)
+    throws IOException;
+
+  /**
+   * Returns the filtering parameters for this event. For example,
+   * most events may be filtered by thread, so one of the parameters
+   * returned should be a <code>Thread</code>.
+   */
+  public abstract Object[] getParameters ();
+
+  /**
+   * Converts this event into to a JDWP packet
+   *
+   * @param dos     the stream to which to write data
+   * @param request the request the wanted this notification
+   * @returns a <code>JdwpPacket</code> of the events
+   */
+  public JdwpPacket toPacket (DataOutputStream dos, EventRequest request)
+  {
+    JdwpPacket pkt;
+    try
+      {
+	dos.writeByte (request.getSuspendPolicy ());
+	dos.writeInt (1);
+	dos.writeByte (_eventKind);
+	dos.writeInt (request.getId ());
+	_writeData (dos);
+
+	pkt = new JdwpCommandPacket (JdwpConstants.CommandSet.Event.value,
+				     JdwpConstants.CommandSet.Event.Composite);
+      }
+    catch (IOException ioe)
+      {
+	pkt = null;
+      }
+
+    return pkt;
+  }
+}

Index: gnu/classpath/jdwp/id/IdManager.java
===================================================================
RCS file: gnu/classpath/jdwp/id/IdManager.java
diff -N gnu/classpath/jdwp/id/IdManager.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ gnu/classpath/jdwp/id/IdManager.java	27 Jun 2005 18:08:40 -0000
@@ -0,0 +1,232 @@
+/* IdManager.java -- a manager for JDWP object/reference type IDs
+   Copyright (C) 2005 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., 59 Temple Place, Suite 330, Boston, MA
+02111-1307 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.id;
+
+import gnu.classpath.jdwp.exception.InvalidClassException;
+import gnu.classpath.jdwp.exception.InvalidObjectException;
+
+import java.lang.ref.Reference;
+import java.lang.ref.ReferenceQueue;
+import java.lang.ref.WeakReference;
+import java.io.DataInputStream;
+import java.io.IOException;
+import java.util.Collections;
+import java.util.Hashtable;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.WeakHashMap;
+
+/**
+ * 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.
+ *
+ * @author Keith Seitz  (keiths@redhat.com)
+ */
+public class IdManager
+{
+  // Reference queues for invalid ObjectIds and ReferenceTypeIds
+  private ReferenceQueue _oidRefQueue;
+  private ReferenceQueue _ridRefQueue;
+
+  /* Mapping of objects (Object) to IDs (ObjectId). Table is a
+     synchronized WeakHashMap. */
+  private Map _oidTable;
+
+  /* Mapping of ID numbers (Long) to IDs (ObjectId). IDs are
+     stored as WeakReferences */
+  private Hashtable _idTable;
+
+  /* Mapping of class (Class) to IDs (ReferenceTypeId) for reference
+     types. Table is a synchronized WeakHashMap. */
+  private Map _classTable;
+
+  /* Mapping of ID numbers (Long) to reference type IDs (ReferenceTypeId).
+     IDs are stored as WeakReferences */
+  private Hashtable _ridTable;
+
+  /**
+   * Constructs a new <code>IdManager</code>
+   */
+  public IdManager ()
+  {
+    _oidRefQueue = new ReferenceQueue ();
+    _ridRefQueue = new ReferenceQueue ();
+    _oidTable = Collections.synchronizedMap (new WeakHashMap (50));
+    _idTable = new Hashtable (50);
+    _classTable = Collections.synchronizedMap (new WeakHashMap (20));
+    _ridTable = new Hashtable (20);
+  }
+
+  // Updates the ID tables, removing IDs whose objects/classes have
+  // been garbage collected.
+  private void _update ()
+  {
+    Reference ref;
+    while ((ref = _oidRefQueue.poll ()) != null)
+      {
+	ObjectId id = (ObjectId) ref.get ();
+	_oidTable.remove (new Long (id.getId ()));
+      }
+
+    while ((ref = _ridRefQueue.poll ()) != null)
+      {
+	ReferenceTypeId id = (ReferenceTypeId) ref.get ();
+	_ridTable.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 getId (Object theObject)
+  {
+    ObjectId id = (ObjectId) _oidTable.get (theObject);
+    if (id == null)
+      {
+	// update the tables -- this is an arbitrary place to put this
+	_update ();
+
+	// Object not found. Make new id for it
+	id = JdwpIdFactory.newId (theObject);
+	_oidTable.put (theObject, id);
+	_idTable.put (new Long (id.getId ()),
+		      new WeakReference (id, _oidRefQueue));
+      }
+
+    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
+  {
+    WeakReference ref = (WeakReference) _idTable.get (new Long (id));
+    ObjectId oid = (ObjectId) ref.get ();
+    if (oid == null)
+      throw new InvalidObjectException (id);
+ 
+    return oid;
+  }
+
+  /**
+   * Reads a numerical ID from the stream, returning
+   * the actual ID associated with it
+   *
+   * @returns the object id
+   * @throws IOException for any errors reading from the stream
+   * @throws InvaildObjectException if ID is not found
+   */
+  public ObjectId readId (DataInputStream is)
+    throws IOException, InvalidObjectException
+  {
+    // All IDs are longs, making this really easy
+    long nid = is.readLong ();
+    return get (nid);
+  }
+
+  /**
+   * Gets the reference type id for the given class, creating
+   * a new one if it does not already have an id
+   *
+   * @param theClazz  the class for which to get an ID
+   * @returns  the ID of the class
+   */
+  public ReferenceTypeId getReferenceTypeId (Class clazz)
+  {
+    ReferenceTypeId id = (ReferenceTypeId)_classTable.get (clazz);
+    if (id == null)
+      {
+	// Object not found. Make new id for it
+	id = JdwpIdFactory.newReferenceTypeId (clazz);
+	_classTable.put (clazz, id);
+	_ridTable.put (new Long (id.getId ()),
+		       new WeakReference (id, _ridRefQueue));
+      }
+
+    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
+  {
+    WeakReference ref = (WeakReference) _ridTable.get (new Long (id));
+    ReferenceTypeId rid = (ReferenceTypeId) ref.get ();
+    if (rid == null)
+      throw new InvalidClassException (id);
+ 
+    return rid;
+  }
+
+  /**
+   * Reads a numerical ID from the stream, returning
+   * the actual reference type ID associated with it
+   *
+   * @returns the JdwpId
+   * @throws IOException for any errors reading from the stream
+   * @throws InvaildObjectException if ID is not found
+   */
+  public ReferenceTypeId readReferenceTypeId (DataInputStream is)
+    throws IOException, InvalidClassException
+  {
+    // All IDs are longs, making this really easy
+    long nid = is.readLong ();
+    return getReferenceType (nid);
+  }
+}