fostore20/src/java/org/apache/jdo/impl/fostore/AID.java - db-jdo - Git at Google

 /*
  * Copyright 2005 The Apache Software Foundation.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 package org.apache.jdo.impl.fostore;

 import java.io.DataInput;
 import java.io.DataOutput;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.io.IOException;
 import java.util.Arrays;

 import java.security.AccessController;
 import java.security.MessageDigest;
 import java.security.PrivilegedAction;
 import java.security.NoSuchAlgorithmException;

 import javax.jdo.JDOFatalException;
 import javax.jdo.JDOFatalInternalException;
 import javax.jdo.JDOUserException;
 import javax.jdo.JDOFatalUserException;
 import javax.jdo.spi.JDOImplHelper;
 import javax.jdo.spi.PersistenceCapable;

 import org.apache.jdo.pm.PersistenceManagerInternal;
 import org.apache.jdo.state.StateManagerInternal;
 import org.apache.jdo.util.I18NHelper;


 /**
  * Represents the identity of a JDO object in the File/Object store.  This
  * implementation uses application identity.  The identity is based on the class
  * of the object and a byte[] buffer that represents values in the user
  * object Id instance which creates a unique identifier within that class.
  * These ID's are unique only within a single datastore.
  * <p>
  *
  * @author Marina Vatkina
  */
 public class AID extends OID {

     // These bytes represent user ID:
     private byte[] buffer;

     // Hashcode uniquely identifying this AID via UID.
     private int hashCode;

     // CLID for the superclass that corresponds to the user defined
     // key class.
     private long sCLIDBits;

     /** I18N support. */
     private static final I18NHelper msg = I18NHelper.getInstance(I18N.NAME);

     /** JDOImplHelper instance */
     private final static JDOImplHelper jdoImplHelper =
         (JDOImplHelper) AccessController.doPrivileged (
             new PrivilegedAction () {
                 public Object run () {
                     try {
                         return JDOImplHelper.getInstance();
                     }
                     catch (SecurityException e) {
                         throw new JDOFatalUserException (msg.msg(
                             e.getMessage()), e); // NOI18N
                     }
                 }
             }
         );

     /**
      * Default constructor.
      */
     public AID() {
         super();
         sCLIDBits = getCLID().getId();
     }

     /**
     * Creates an AID with the given value.
     */
     public AID(long oid) {
         super(oid);
         sCLIDBits = getCLID().getId();
     }

     /**
     * Create and return a new instance of AID.
     * @return a new instance of AID.
     */
     static AID create(Class pcClass, PersistenceCapable pc,
                                       Object userOid,
                                       PersistenceManagerInternal pm,
                                       FOStorePMF pmf) {
         boolean fromPC = false;
         if (userOid == null) {
             fromPC = true;
             userOid = pc.jdoNewObjectIdInstance();
             pc.jdoCopyKeyFieldsToObjectId(userOid);
         }
         AID rc = new AID();
         rc.createBuffer(userOid, pcClass, pmf, fromPC, pc);
         rc.setSuperCLIDBits(pcClass, userOid.getClass(), pm, pmf);

         return rc;
     }


     /**
     * Determines if this AID is equal to another.
     * @param other The other AID in the equality comparison.
     * @return True if they are equal, false otherwise.
     */
     public boolean equals(Object other) {
         boolean rc = false;
         if (other instanceof AID) {
             AID o = (AID)other;

             long uidBits = this.oid & UID_MASK;
             long o_uidBits = o.oid & UID_MASK;

             // It is enough to compare super class CLID bits,
             // as there are no 2 subclasses with the same uid.
             rc = Arrays.equals(this.buffer, o.buffer) &&
                 (uidBits == o_uidBits) && (sCLIDBits == o.sCLIDBits);
         }
         return rc;
     }

     /**
     * Returns a String representation of this AID.  Includes whether or not
     * the instance is provisional, and its reserved bits, if they are set.
     */
     public String toString() {
         StringBuffer rc =
             new StringBuffer(
                 "OID: " + // NOI18N
                 ((oid & CLID_MASK) >> CLID_SHIFT) +
                 "-0x") ; // NOI18N
         for (int i = 0; i < buffer.length; i++) {
             rc.append(toHexString(buffer[i]));
         }

         if (isProvisional()) {
             rc.append(" (provisional)"); // NOI18N
         }
         long res = oid & RESERVED_MASK;
         if (res > 0) {
             res = res >> RESERVED_SHIFT;
             rc.append(" (reserved=" + res + ")"); // NOI18N
         }
         rc.append(" (super CLID=" + sCLIDBits + ")"); // NOI18N
         return rc.toString();
     }

     /**
     * Returns the id itself in String form, for debugging.
     */
     public String oidString() {
         return "" + oid; // NOI18N
     }

     /**
     * Provides a unique hashCode for this AID.
     */
     public int hashCode() {
         if (0 == hashCode) {
             hashCode = new Long(oid & UID_MASK).hashCode();
         }
         return hashCode;
     }


     /**
      * Returns true for application identity type for this OID.
      */
     boolean isApplicationIdentity() {
         return true;
     }

     /**
      * Returns false for datastore identity type for this OID.
      */
     boolean isDataStoreIdentity() {
         return false;
     }

     /**
      * Returns copy of the requested oid to be accessed by the user.
      */
     Object getExternalObjectId(PersistenceCapable pc) {

         // Create and return user Oid value from persistence-capable
         // instance.
         Object rc = pc.jdoNewObjectIdInstance();
         pc.jdoCopyKeyFieldsToObjectId(rc);

         return rc;
     }

     //
     // Serialization
     // We provide the {write,read}Object methods for java.io.Serialization, so
     // that we know exactly what's being written and read.  We also have
     // methods used elsewhere in the fostore package that don't rely
     // ObjectOutput stuff.
     //

     /**
     * Writes this AID to the output stream.
     */
     public void writeObject(ObjectOutputStream out) throws IOException {
         write(out);
     }

     /**
     * Reads this AID's value from the input stream.
     */
     public void readObject(ObjectInputStream in) throws IOException {
         boolean applicationIdentity = in.readBoolean();
         oid = in.readLong();
         this.readBuffer(in);
     }

     /**
     * Writes this AID to the output stream.
     */
     void write(DataOutput out) throws IOException {
         if (logger.isDebugEnabled()) {
                 logger.debug("AID.write: " + this + " oid: " + oid);  // NOI18N
         }
         out.writeBoolean(true);
         out.writeLong(oid);
         out.writeLong(sCLIDBits);
         out.writeInt(buffer.length);
         out.write(buffer);
     }

     /**
     * Reads AID buffer's value from the input stream.
     */
     void readBuffer(DataInput in) throws IOException {
         try {
             sCLIDBits = in.readLong();
             int length = in.readInt();
             buffer = new byte[length];
             in.readFully(buffer);
         } catch (IOException ex) {
             throw new FOStoreFatalIOException(
                 AID.class, "read", ex); // NOI18N
         }
         if (logger.isDebugEnabled()) {
                 logger.debug("AID.read: " + this);  // NOI18N
         }
     }

     /** Replaces provisional oid with real oid (datastore identity only)
      * @param realOID as OID instance
      * @param pmf as FOStorePMF
      * @param sm as StateManagerInternal
      */
     void replaceProvisionalOIDWithReal(OID realOID, FOStorePMF pmf,
                                            StateManagerInternal sm) {
         // Construct oid from new CLID and existing UID.
         if (logger.isDebugEnabled()) {
             logger.debug("AID.replaceProvisionalOIDWithReal: " +   // NOI18N
                 this + " with: " + realOID); // NOI18N
         }
         OID oldOid = this.copy();

         long clidBits = realOID.oid & CLID_MASK;
         long uidBits = this.oid & UID_MASK;
         this.oid = clidBits | uidBits;

         if (sm != null && sm.getPCClass() != null) {
             // Calculate superclass version of this OID for future lookup.
             setSuperCLIDBits(sm.getPCClass(), null, sm.getPersistenceManager(), pmf);

         } else if (oldOid.isProvisional()) {
             // else just sync the values.
             sCLIDBits = getCLID().getId();
         }
     }

     /**
      * Returns copy of the requested oid.
      */
     OID copy() {
         AID rc = new AID();
         rc.oid = oid;
         rc.sCLIDBits = sCLIDBits;
         rc.buffer = new byte[buffer.length];
         System.arraycopy(buffer, 0, rc.buffer, 0, buffer.length);

         return rc;
     }

     /**
      * Copy key fields from OID into PC instance. No-op for the
      * datastore identity type for this OID.
      * @param sm as StateManagerInternal
      * @param pmf as FOStorePMF
      * @param pcClass Class of the PC instance.
      * @param pkfields array of PK field numbers.
      */
     void copyKeyFieldsToPC(StateManagerInternal sm, FOStorePMF pmf,
                                     Class pcClass, int[] pkfields) {
         FieldFetcher ff =
             new FieldFetcher(new FOStoreInput(buffer, 0, buffer.length),
                  pmf.getModel(),
                  sm.getPersistenceManager(),
                  pcClass.getClassLoader(),
                  false); // do not skip other fields
         ff.setPCClass(pcClass);

         sm.replaceFields(pkfields, ff);
     }

     //
     // Internal methods.
     //

     private void createBuffer (Object userOid, Class pcClass, FOStorePMF pmf,
             boolean fromPC, PersistenceCapable pc) {
         if (logger.isDebugEnabled()) {
             logger.debug("AID.createBuffer: " +   // NOI18N
                 " for userOid: " + userOid + ", pcClass: " + pcClass.getName()); // NOI18N
         }
         FOStoreModel model = pmf.getModel();
         CLID clid = model.getCLID(pcClass);
         long clidBits = clid.getId();
         clidBits <<= CLID_SHIFT;
         if (clid.isProvisional()) {
             clidBits |= PROV_CLID_MASK;
         }

         FOStoreOutput out = new FOStoreOutput();
         AIDTranscriber aidTranscriber = new AIDTranscriber(out, pcClass, pmf);
         try {
             jdoImplHelper.copyKeyFieldsFromObjectId(
                     pcClass, aidTranscriber, userOid);
         } catch (NullPointerException npe) {
             if (fromPC) {
                 throw new JDOUserException(msg.msg("EXC_MakePersistentKeyFieldNull",
                     npe.getMessage()), pc);
             } else {
                 throw new JDOUserException(msg.msg("EXC_GetObjectByIdKeyFieldNull",
                     npe.getMessage()), userOid);
             }
         }

         // Read the field values part of the block.
         int length = out.getPos();
         byte[] temp = out.getBuf();
         buffer = new byte[length];
         System.arraycopy(temp, 0, buffer, 0, length);

         long uidBits = computeUID();
         oid = clidBits | (uidBits & UID_MASK);
         if (logger.isDebugEnabled()) {
             logger.debug("AID.createBuffer: " +   // NOI18N
                 this + " oid: " + Long.toHexString(oid)); // NOI18N
         }

     }

     /**
      * Sets CLID bits for the superclass that corresponds to the user
      * defined key class.
      * @param pcClass the class of the persisntence-capable instance or
      * null if not known.
      * @param keyClass the class of the user defined key or null if not
      * known.
      * @param pm the PersistenceManagerInternal that requested the operation.
      * @param pmf the FOStorePMF that requested the operation.
      */
     private void setSuperCLIDBits(Class pcClass, Class keyClass,
                                   PersistenceManagerInternal pm,
                                   FOStorePMF pmf) {
         long rc = getCLID().getId();

         if (pcClass != null) {
             if (keyClass == null) {
                 keyClass = jdoImplHelper.newObjectIdInstance(pcClass).getClass();
             }
             try {

                 Class cls = pm.loadPCClassForObjectIdClass(keyClass);
                 if (cls != null) {
                     rc = pmf.getModel().getCLID(cls).getId();

                     if (logger.isDebugEnabled()) {
                         logger.debug("AID.getSuperCLID: " + rc);  // NOI18N
                     }
                 }
             } catch (Exception e) {
                 // ignore - will set superclass to the pcClass.
             }

         }
         sCLIDBits = rc;
     }

     /**
      * Compute unique user Id from the buffer.
      */
     private long computeUID() {
         long rc = 0;
         try {
             MessageDigest md = MessageDigest.getInstance("SHA"); // NOI18N
             byte hasharray[] = md.digest(buffer);
             for (int i = 0; i < Math.min(8, hasharray.length); i++) {
                 rc += (long)(hasharray[i] & 255) << (i * 8);
             }

         } catch (NoSuchAlgorithmException ex) {
             throw new JDOFatalInternalException(
                 msg.msg("ERR_Algorithm"), ex); // NOI18N
         }
         return rc;
     }

     /**
      * Covert byte into 2-digit hexadecimal String.
      */
     private static String toHexString(int b) {
         char a = (b < 0)? 'F' : '0';
         return "" + a + hexDigit[(b & 0xF)]; //NOI18N
     }

     /** A table of hex digits */
     private static final char[] hexDigit = {
         '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
     };

 }
	/*
	* Copyright 2005 The Apache Software Foundation.
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	package org.apache.jdo.impl.fostore;

	import java.io.DataInput;
	import java.io.DataOutput;
	import java.io.ObjectInputStream;
	import java.io.ObjectOutputStream;
	import java.io.IOException;
	import java.util.Arrays;

	import java.security.AccessController;
	import java.security.MessageDigest;
	import java.security.PrivilegedAction;
	import java.security.NoSuchAlgorithmException;

	import javax.jdo.JDOFatalException;
	import javax.jdo.JDOFatalInternalException;
	import javax.jdo.JDOUserException;
	import javax.jdo.JDOFatalUserException;
	import javax.jdo.spi.JDOImplHelper;
	import javax.jdo.spi.PersistenceCapable;

	import org.apache.jdo.pm.PersistenceManagerInternal;
	import org.apache.jdo.state.StateManagerInternal;
	import org.apache.jdo.util.I18NHelper;


	/**
	* Represents the identity of a JDO object in the File/Object store. This
	* implementation uses application identity. The identity is based on the class
	* of the object and a byte[] buffer that represents values in the user
	* object Id instance which creates a unique identifier within that class.
	* These ID's are unique only within a single datastore.
	* <p>
	*
	* @author Marina Vatkina
	*/
	public class AID extends OID {

	// These bytes represent user ID:
	private byte[] buffer;

	// Hashcode uniquely identifying this AID via UID.
	private int hashCode;

	// CLID for the superclass that corresponds to the user defined
	// key class.
	private long sCLIDBits;

	/** I18N support. */
	private static final I18NHelper msg = I18NHelper.getInstance(I18N.NAME);

	/** JDOImplHelper instance */
	private final static JDOImplHelper jdoImplHelper =
	(JDOImplHelper) AccessController.doPrivileged (
	new PrivilegedAction () {
	public Object run () {
	try {
	return JDOImplHelper.getInstance();
	}
	catch (SecurityException e) {
	throw new JDOFatalUserException (msg.msg(
	e.getMessage()), e); // NOI18N
	}
	}
	}
	);

	/**
	* Default constructor.
	*/
	public AID() {
	super();
	sCLIDBits = getCLID().getId();
	}

	/**
	* Creates an AID with the given value.
	*/
	public AID(long oid) {
	super(oid);
	sCLIDBits = getCLID().getId();
	}

	/**
	* Create and return a new instance of AID.
	* @return a new instance of AID.
	*/
	static AID create(Class pcClass, PersistenceCapable pc,
	Object userOid,
	PersistenceManagerInternal pm,
	FOStorePMF pmf) {
	boolean fromPC = false;
	if (userOid == null) {
	fromPC = true;
	userOid = pc.jdoNewObjectIdInstance();
	pc.jdoCopyKeyFieldsToObjectId(userOid);
	}
	AID rc = new AID();
	rc.createBuffer(userOid, pcClass, pmf, fromPC, pc);
	rc.setSuperCLIDBits(pcClass, userOid.getClass(), pm, pmf);

	return rc;
	}


	/**
	* Determines if this AID is equal to another.
	* @param other The other AID in the equality comparison.
	* @return True if they are equal, false otherwise.
	*/
	public boolean equals(Object other) {
	boolean rc = false;
	if (other instanceof AID) {
	AID o = (AID)other;

	long uidBits = this.oid & UID_MASK;
	long o_uidBits = o.oid & UID_MASK;

	// It is enough to compare super class CLID bits,
	// as there are no 2 subclasses with the same uid.
	rc = Arrays.equals(this.buffer, o.buffer) &&
	(uidBits == o_uidBits) && (sCLIDBits == o.sCLIDBits);
	}
	return rc;
	}

	/**
	* Returns a String representation of this AID. Includes whether or not
	* the instance is provisional, and its reserved bits, if they are set.
	*/
	public String toString() {
	StringBuffer rc =
	new StringBuffer(
	"OID: " + // NOI18N
	((oid & CLID_MASK) >> CLID_SHIFT) +
	"-0x") ; // NOI18N
	for (int i = 0; i < buffer.length; i++) {
	rc.append(toHexString(buffer[i]));
	}

	if (isProvisional()) {
	rc.append(" (provisional)"); // NOI18N
	}
	long res = oid & RESERVED_MASK;
	if (res > 0) {
	res = res >> RESERVED_SHIFT;
	rc.append(" (reserved=" + res + ")"); // NOI18N
	}
	rc.append(" (super CLID=" + sCLIDBits + ")"); // NOI18N
	return rc.toString();
	}

	/**
	* Returns the id itself in String form, for debugging.
	*/
	public String oidString() {
	return "" + oid; // NOI18N
	}

	/**
	* Provides a unique hashCode for this AID.
	*/
	public int hashCode() {
	if (0 == hashCode) {
	hashCode = new Long(oid & UID_MASK).hashCode();
	}
	return hashCode;
	}


	/**
	* Returns true for application identity type for this OID.
	*/
	boolean isApplicationIdentity() {
	return true;
	}

	/**
	* Returns false for datastore identity type for this OID.
	*/
	boolean isDataStoreIdentity() {
	return false;
	}

	/**
	* Returns copy of the requested oid to be accessed by the user.
	*/
	Object getExternalObjectId(PersistenceCapable pc) {

	// Create and return user Oid value from persistence-capable
	// instance.
	Object rc = pc.jdoNewObjectIdInstance();
	pc.jdoCopyKeyFieldsToObjectId(rc);

	return rc;
	}

	//
	// Serialization
	// We provide the {write,read}Object methods for java.io.Serialization, so
	// that we know exactly what's being written and read. We also have
	// methods used elsewhere in the fostore package that don't rely
	// ObjectOutput stuff.
	//

	/**
	* Writes this AID to the output stream.
	*/
	public void writeObject(ObjectOutputStream out) throws IOException {
	write(out);
	}

	/**
	* Reads this AID's value from the input stream.
	*/
	public void readObject(ObjectInputStream in) throws IOException {
	boolean applicationIdentity = in.readBoolean();
	oid = in.readLong();
	this.readBuffer(in);
	}

	/**
	* Writes this AID to the output stream.
	*/
	void write(DataOutput out) throws IOException {
	if (logger.isDebugEnabled()) {
	logger.debug("AID.write: " + this + " oid: " + oid); // NOI18N
	}
	out.writeBoolean(true);
	out.writeLong(oid);
	out.writeLong(sCLIDBits);
	out.writeInt(buffer.length);
	out.write(buffer);
	}

	/**
	* Reads AID buffer's value from the input stream.
	*/
	void readBuffer(DataInput in) throws IOException {
	try {
	sCLIDBits = in.readLong();
	int length = in.readInt();
	buffer = new byte[length];
	in.readFully(buffer);
	} catch (IOException ex) {
	throw new FOStoreFatalIOException(
	AID.class, "read", ex); // NOI18N
	}
	if (logger.isDebugEnabled()) {
	logger.debug("AID.read: " + this); // NOI18N
	}
	}

	/** Replaces provisional oid with real oid (datastore identity only)
	* @param realOID as OID instance
	* @param pmf as FOStorePMF
	* @param sm as StateManagerInternal
	*/
	void replaceProvisionalOIDWithReal(OID realOID, FOStorePMF pmf,
	StateManagerInternal sm) {
	// Construct oid from new CLID and existing UID.
	if (logger.isDebugEnabled()) {
	logger.debug("AID.replaceProvisionalOIDWithReal: " + // NOI18N
	this + " with: " + realOID); // NOI18N
	}
	OID oldOid = this.copy();

	long clidBits = realOID.oid & CLID_MASK;
	long uidBits = this.oid & UID_MASK;
	this.oid = clidBits \| uidBits;

	if (sm != null && sm.getPCClass() != null) {
	// Calculate superclass version of this OID for future lookup.
	setSuperCLIDBits(sm.getPCClass(), null, sm.getPersistenceManager(), pmf);

	} else if (oldOid.isProvisional()) {
	// else just sync the values.
	sCLIDBits = getCLID().getId();
	}
	}

	/**
	* Returns copy of the requested oid.
	*/
	OID copy() {
	AID rc = new AID();
	rc.oid = oid;
	rc.sCLIDBits = sCLIDBits;
	rc.buffer = new byte[buffer.length];
	System.arraycopy(buffer, 0, rc.buffer, 0, buffer.length);

	return rc;
	}

	/**
	* Copy key fields from OID into PC instance. No-op for the
	* datastore identity type for this OID.
	* @param sm as StateManagerInternal
	* @param pmf as FOStorePMF
	* @param pcClass Class of the PC instance.
	* @param pkfields array of PK field numbers.
	*/
	void copyKeyFieldsToPC(StateManagerInternal sm, FOStorePMF pmf,
	Class pcClass, int[] pkfields) {
	FieldFetcher ff =
	new FieldFetcher(new FOStoreInput(buffer, 0, buffer.length),
	pmf.getModel(),
	sm.getPersistenceManager(),
	pcClass.getClassLoader(),
	false); // do not skip other fields
	ff.setPCClass(pcClass);

	sm.replaceFields(pkfields, ff);
	}

	//
	// Internal methods.
	//

	private void createBuffer (Object userOid, Class pcClass, FOStorePMF pmf,
	boolean fromPC, PersistenceCapable pc) {
	if (logger.isDebugEnabled()) {
	logger.debug("AID.createBuffer: " + // NOI18N
	" for userOid: " + userOid + ", pcClass: " + pcClass.getName()); // NOI18N
	}
	FOStoreModel model = pmf.getModel();
	CLID clid = model.getCLID(pcClass);
	long clidBits = clid.getId();
	clidBits <<= CLID_SHIFT;
	if (clid.isProvisional()) {
	clidBits \|= PROV_CLID_MASK;
	}

	FOStoreOutput out = new FOStoreOutput();
	AIDTranscriber aidTranscriber = new AIDTranscriber(out, pcClass, pmf);
	try {
	jdoImplHelper.copyKeyFieldsFromObjectId(
	pcClass, aidTranscriber, userOid);
	} catch (NullPointerException npe) {
	if (fromPC) {
	throw new JDOUserException(msg.msg("EXC_MakePersistentKeyFieldNull",
	npe.getMessage()), pc);
	} else {
	throw new JDOUserException(msg.msg("EXC_GetObjectByIdKeyFieldNull",
	npe.getMessage()), userOid);
	}
	}

	// Read the field values part of the block.
	int length = out.getPos();
	byte[] temp = out.getBuf();
	buffer = new byte[length];
	System.arraycopy(temp, 0, buffer, 0, length);

	long uidBits = computeUID();
	oid = clidBits \| (uidBits & UID_MASK);
	if (logger.isDebugEnabled()) {
	logger.debug("AID.createBuffer: " + // NOI18N
	this + " oid: " + Long.toHexString(oid)); // NOI18N
	}

	}

	/**
	* Sets CLID bits for the superclass that corresponds to the user
	* defined key class.
	* @param pcClass the class of the persisntence-capable instance or
	* null if not known.
	* @param keyClass the class of the user defined key or null if not
	* known.
	* @param pm the PersistenceManagerInternal that requested the operation.
	* @param pmf the FOStorePMF that requested the operation.
	*/
	private void setSuperCLIDBits(Class pcClass, Class keyClass,
	PersistenceManagerInternal pm,
	FOStorePMF pmf) {
	long rc = getCLID().getId();

	if (pcClass != null) {
	if (keyClass == null) {
	keyClass = jdoImplHelper.newObjectIdInstance(pcClass).getClass();
	}
	try {

	Class cls = pm.loadPCClassForObjectIdClass(keyClass);
	if (cls != null) {
	rc = pmf.getModel().getCLID(cls).getId();

	if (logger.isDebugEnabled()) {
	logger.debug("AID.getSuperCLID: " + rc); // NOI18N
	}
	}
	} catch (Exception e) {
	// ignore - will set superclass to the pcClass.
	}

	}
	sCLIDBits = rc;
	}

	/**
	* Compute unique user Id from the buffer.
	*/
	private long computeUID() {
	long rc = 0;
	try {
	MessageDigest md = MessageDigest.getInstance("SHA"); // NOI18N
	byte hasharray[] = md.digest(buffer);
	for (int i = 0; i < Math.min(8, hasharray.length); i++) {
	rc += (long)(hasharray[i] & 255) << (i * 8);
	}

	} catch (NoSuchAlgorithmException ex) {
	throw new JDOFatalInternalException(
	msg.msg("ERR_Algorithm"), ex); // NOI18N
	}
	return rc;
	}

	/**
	* Covert byte into 2-digit hexadecimal String.
	*/
	private static String toHexString(int b) {
	char a = (b < 0)? 'F' : '0';
	return "" + a + hexDigit[(b & 0xF)]; //NOI18N
	}

	/** A table of hex digits */
	private static final char[] hexDigit = {
	'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
	};

	}