fostore20/src/java/org/apache/jdo/impl/fostore/GetExtentRequest.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.IOException;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.NoSuchElementException;

 import javax.jdo.Extent;
 import javax.jdo.JDOHelper;
 import javax.jdo.JDOUserException;
 import javax.jdo.PersistenceManager;

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


 /**
  * Represents a request to get the extent of a class and possibly its
  * subclasses.
  *
  * @author Dave Bristor
  */
 //
 // This is client-side code.  It does not need to live in the server.
 //
 class GetExtentRequest extends AbstractRequest {
     /** The PersistenceManagerInternal that is making this request. */
     private final PersistenceManagerInternal pm;

     /** The class of the extent sought by this request. */
     private final Class cls;

     /** If true retrieve instances of cls and its subclasses, otherwise just
      * of cls. */
     private final boolean subclasses;

     /** Maximum number of instances that should be returned at a time. */
     private static final int maxInstances;

     /** Extent returned to user. */
     private FOStoreExtent extent;

     /** List of returned instances */
     private ArrayList instances;

     /** List of returned object Ids */
     private ArrayList oids;

     static {
         int max = 100;
         try {
             String property = (String)AccessController.doPrivileged(
                 new PrivilegedAction () {
                     public Object run () {
                         return System.getProperty("maxInstances"); // NOI18N
                     }
                 }
                 );
             max = Integer.parseInt(property);
         } catch (SecurityException ex) {
             // cannot read maxInstances flag => log warning
             if (logger.isWarnEnabled())
                 logger.warn(msg.msg("MSG_CannotGetSystemProperty", //NOI18N
                     "maxInstances", ex.toString())); //NOI18N
         } catch (Exception ex) {
             // use default
         }
         maxInstances = max;
     }

     GetExtentRequest(FOStoreExtent extent, Class cls, boolean subclasses,  Message m,
                      PersistenceManagerInternal pm) {

         super(m, (FOStorePMF)pm.getPersistenceManagerFactory());
         this.pm = pm;
         this.cls = cls;
         this.subclasses = subclasses;
         this.extent = extent;
     }

     /**
      * @see AbstractRequest#doRequestBody
      * @see InsertRequest#doRequestBody
      */
     protected void doRequestBody() throws IOException {
         //
         // The format of this request is variable, depending on whether or not
         // we already have in-client metadata for the given class.
         //
         // If we do have in-client metadata for the given class:
         //
         // int: maximum number of instances to return
         // boolean: true
         // clid of the class
         // boolean: true if subclasses, false otherwise
         //
         // Otherwise:
         //
         // int: maximum number of instances to return
         // boolean: flase
         // String name of the class
         // FOStoreSchemaUID of the class.
         // boolean: true if subclasses, false otherwise
         //

         FOStoreModel model = pmf.getModel();
         CLID clid = model.getCLID(cls);
         out.writeInt(maxInstances);
         if (null != clid && ! clid.isProvisional()) {
             out.writeBoolean(true);
             clid.write(out);
             if (logger.isDebugEnabled()) {
                 logger.debug("GetExtentRequest.dRB: " + clid // NOI18N
                                + " subclasses=" + subclasses); // NOI18N
             }
         } else {
             out.writeBoolean(false);
             out.writeUTF(cls.getName());
             FOStoreSchemaUID fsuid = FOStoreSchemaUID.lookup(cls, model);
             fsuid.write(out);
             if (logger.isDebugEnabled()) {
                 logger.debug(
                     "GetExtentRequest.dRB: " + cls.getName() // NOI18N
                     + " subclasses=" + subclasses); // NOI18N
             }
         }
         out.writeBoolean(subclasses);
     }

     /**
      * Handles replies to GetExtentRequests.
      * The format of the reply is:
      * <pre>
      * int: count of number of instances in the extent
      * int: count of the number of instances returned
      * int: count of the number of oids returned
      * that many instances
      * </pre>
      * The number of instances returned + number of oid returned = number
      * of instances in the extent.  This is for performance: we don't
      * want to return *all* the instances at once: we return some, plus
      * information so that we can get the rest, if the user requests so.
      * <p>
      * The status might be Status.WARN, in which case there were OID's in
      * the database extent which were unreadable.  But the count should
      * be for the actual number of objects returned.
      */
      public void handleReply(Status status, DataInput in, int length)
          throws IOException {


          int extentSize = in.readInt();
          int numInstances = in.readInt();
          int numOIDs = in.readInt();
          if (logger.isDebugEnabled()) {
              logger.debug(
                  "GER.hR/1: extentSize=" + extentSize + // NOI18N
                  ", numInstances=" + numInstances + // NOI18N
                  ", numOIDs=" + numOIDs); // NOI18N
          }

          // Get instances for the extent
          instances =
              readInstances(in, numInstances, pmf.getModel(), pm, cls);

          // Add OIDs for the extent
          oids = new ArrayList(numOIDs);
          for (int i = 0; i < numOIDs; i++) {
              OID oid = OID.read(in);
              if (logger.isDebugEnabled()) {
                  logger.debug("GER.hR/4: " + oid + // NOI18N
                                 " " + Tester.toHex(oid.oid, 16)); // NOI18N
              }
              oids.add(oid);
          }
     }


     /**
      * Reads instances from given DataInput using a {@link FieldFetcher}.
      * @param in DataInput from which instances are read.
      * @param numInstances Number of instances to read from <code>in</code>.
      * @param model Model required to by {@link FieldFetcher}.
      * @param pm PersistenceManagerInternal required  {@link FieldFetcher}.
      * @param cls Candidate Class for which instances are being obtained.
      * @return ArrayList of instances read.
      */
     static ArrayList readInstances(DataInput in, int numInstances,
                                    FOStoreModel model,
                                    PersistenceManagerInternal pm,
                                    Class cls)
         throws IOException {

          ArrayList rc = new ArrayList(numInstances);
          for (int i = 0; i < numInstances; i++) {
              OID oid = OID.read(in);
              if (logger.isDebugEnabled()) {
                  logger.debug("GER.readInstances/1: " + oid + // NOI18N
                                 " " + Tester.toHex(oid.oid, 16)); // NOI18N
              }

              // Fill in pc's fields.
              int objLength = in.readInt();
              if (logger.isDebugEnabled()) {
                  logger.debug(
                      "GER.readInstances/2: reading " + objLength +  // NOI18N
                      " bytes"); // NOI18N
              }
              byte data[] = new byte[objLength];
              in.readFully(data);
              FieldFetcher ff =
                  new FieldFetcher(new FOStoreInput(data, 0, objLength),
                                   model,
                                   pm,
                                   cls.getClassLoader());
              StateManagerInternal sm = ff.fetch(oid);
              Object pc = sm.getObject();
              rc.add(pc);
          }
          return rc;
     }

     /** Returns max number of instances */
     int getMaxInstances() {
         return maxInstances;
     }

     /** Returns the list of instances */
     ArrayList getInstances() {
         return instances;
     }

     /** Returns the list of object id's */
     ArrayList getOIDs() {
         return oids;
     }

     /** Returns the Extent associated with this request */
     Extent getExtent() {
         return extent;
     }

 }
	/*
	* 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.IOException;
	import java.security.AccessController;
	import java.security.PrivilegedAction;
	import java.util.ArrayList;
	import java.util.HashSet;
	import java.util.Iterator;
	import java.util.NoSuchElementException;

	import javax.jdo.Extent;
	import javax.jdo.JDOHelper;
	import javax.jdo.JDOUserException;
	import javax.jdo.PersistenceManager;

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


	/**
	* Represents a request to get the extent of a class and possibly its
	* subclasses.
	*
	* @author Dave Bristor
	*/
	//
	// This is client-side code. It does not need to live in the server.
	//
	class GetExtentRequest extends AbstractRequest {
	/** The PersistenceManagerInternal that is making this request. */
	private final PersistenceManagerInternal pm;

	/** The class of the extent sought by this request. */
	private final Class cls;

	/** If true retrieve instances of cls and its subclasses, otherwise just
	* of cls. */
	private final boolean subclasses;

	/** Maximum number of instances that should be returned at a time. */
	private static final int maxInstances;

	/** Extent returned to user. */
	private FOStoreExtent extent;

	/** List of returned instances */
	private ArrayList instances;

	/** List of returned object Ids */
	private ArrayList oids;

	static {
	int max = 100;
	try {
	String property = (String)AccessController.doPrivileged(
	new PrivilegedAction () {
	public Object run () {
	return System.getProperty("maxInstances"); // NOI18N
	}
	}
	);
	max = Integer.parseInt(property);
	} catch (SecurityException ex) {
	// cannot read maxInstances flag => log warning
	if (logger.isWarnEnabled())
	logger.warn(msg.msg("MSG_CannotGetSystemProperty", //NOI18N
	"maxInstances", ex.toString())); //NOI18N
	} catch (Exception ex) {
	// use default
	}
	maxInstances = max;
	}

	GetExtentRequest(FOStoreExtent extent, Class cls, boolean subclasses, Message m,
	PersistenceManagerInternal pm) {

	super(m, (FOStorePMF)pm.getPersistenceManagerFactory());
	this.pm = pm;
	this.cls = cls;
	this.subclasses = subclasses;
	this.extent = extent;
	}

	/**
	* @see AbstractRequest#doRequestBody
	* @see InsertRequest#doRequestBody
	*/
	protected void doRequestBody() throws IOException {
	//
	// The format of this request is variable, depending on whether or not
	// we already have in-client metadata for the given class.
	//
	// If we do have in-client metadata for the given class:
	//
	// int: maximum number of instances to return
	// boolean: true
	// clid of the class
	// boolean: true if subclasses, false otherwise
	//
	// Otherwise:
	//
	// int: maximum number of instances to return
	// boolean: flase
	// String name of the class
	// FOStoreSchemaUID of the class.
	// boolean: true if subclasses, false otherwise
	//

	FOStoreModel model = pmf.getModel();
	CLID clid = model.getCLID(cls);
	out.writeInt(maxInstances);
	if (null != clid && ! clid.isProvisional()) {
	out.writeBoolean(true);
	clid.write(out);
	if (logger.isDebugEnabled()) {
	logger.debug("GetExtentRequest.dRB: " + clid // NOI18N
	+ " subclasses=" + subclasses); // NOI18N
	}
	} else {
	out.writeBoolean(false);
	out.writeUTF(cls.getName());
	FOStoreSchemaUID fsuid = FOStoreSchemaUID.lookup(cls, model);
	fsuid.write(out);
	if (logger.isDebugEnabled()) {
	logger.debug(
	"GetExtentRequest.dRB: " + cls.getName() // NOI18N
	+ " subclasses=" + subclasses); // NOI18N
	}
	}
	out.writeBoolean(subclasses);
	}

	/**
	* Handles replies to GetExtentRequests.
	* The format of the reply is:
	* <pre>
	* int: count of number of instances in the extent
	* int: count of the number of instances returned
	* int: count of the number of oids returned
	* that many instances
	* </pre>
	* The number of instances returned + number of oid returned = number
	* of instances in the extent. This is for performance: we don't
	* want to return all the instances at once: we return some, plus
	* information so that we can get the rest, if the user requests so.
	* <p>
	* The status might be Status.WARN, in which case there were OID's in
	* the database extent which were unreadable. But the count should
	* be for the actual number of objects returned.
	*/
	public void handleReply(Status status, DataInput in, int length)
	throws IOException {


	int extentSize = in.readInt();
	int numInstances = in.readInt();
	int numOIDs = in.readInt();
	if (logger.isDebugEnabled()) {
	logger.debug(
	"GER.hR/1: extentSize=" + extentSize + // NOI18N
	", numInstances=" + numInstances + // NOI18N
	", numOIDs=" + numOIDs); // NOI18N
	}

	// Get instances for the extent
	instances =
	readInstances(in, numInstances, pmf.getModel(), pm, cls);

	// Add OIDs for the extent
	oids = new ArrayList(numOIDs);
	for (int i = 0; i < numOIDs; i++) {
	OID oid = OID.read(in);
	if (logger.isDebugEnabled()) {
	logger.debug("GER.hR/4: " + oid + // NOI18N
	" " + Tester.toHex(oid.oid, 16)); // NOI18N
	}
	oids.add(oid);
	}
	}


	/**
	* Reads instances from given DataInput using a {@link FieldFetcher}.
	* @param in DataInput from which instances are read.
	* @param numInstances Number of instances to read from <code>in</code>.
	* @param model Model required to by {@link FieldFetcher}.
	* @param pm PersistenceManagerInternal required {@link FieldFetcher}.
	* @param cls Candidate Class for which instances are being obtained.
	* @return ArrayList of instances read.
	*/
	static ArrayList readInstances(DataInput in, int numInstances,
	FOStoreModel model,
	PersistenceManagerInternal pm,
	Class cls)
	throws IOException {

	ArrayList rc = new ArrayList(numInstances);
	for (int i = 0; i < numInstances; i++) {
	OID oid = OID.read(in);
	if (logger.isDebugEnabled()) {
	logger.debug("GER.readInstances/1: " + oid + // NOI18N
	" " + Tester.toHex(oid.oid, 16)); // NOI18N
	}

	// Fill in pc's fields.
	int objLength = in.readInt();
	if (logger.isDebugEnabled()) {
	logger.debug(
	"GER.readInstances/2: reading " + objLength + // NOI18N
	" bytes"); // NOI18N
	}
	byte data[] = new byte[objLength];
	in.readFully(data);
	FieldFetcher ff =
	new FieldFetcher(new FOStoreInput(data, 0, objLength),
	model,
	pm,
	cls.getClassLoader());
	StateManagerInternal sm = ff.fetch(oid);
	Object pc = sm.getObject();
	rc.add(pc);
	}
	return rc;
	}

	/** Returns max number of instances */
	int getMaxInstances() {
	return maxInstances;
	}

	/** Returns the list of instances */
	ArrayList getInstances() {
	return instances;
	}

	/** Returns the list of object id's */
	ArrayList getOIDs() {
	return oids;
	}

	/** Returns the Extent associated with this request */
	Extent getExtent() {
	return extent;
	}

	}