src/main/java/edu/stanford/ramcloud/JRamCloud.java - spring-open - Gitiles

 /* Copyright (c) 2013 Stanford University
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
  * copyright notice and this permission notice appear in all copies.
  *
  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR(S) DISCLAIM ALL WARRANTIES
  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL AUTHORS BE LIABLE FOR
  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */

 package edu.stanford.ramcloud;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.lang.Integer;

 /*
  * This class provides Java bindings for RAMCloud. Right now it is a rather
  * simple subset of what RamCloud.h defines.
  *
  * Running ``javah'' on this file will generate a C header file with the
  * appropriate JNI function definitions. The glue interfacing to the C++
  * RAMCloud library can be found in JRamCloud.cc.
  *
  * For JNI information, the IBM tutorials and Android developer docs are much
  * better than Sun's at giving an overall intro:
  *      http://www.ibm.com/developerworks/java/tutorials/j-jni/section4.html
  *      http://developer.android.com/training/articles/perf-jni.html
  */
 public class JRamCloud {
     static {
         System.loadLibrary("edu_stanford_ramcloud_JRamCloud");
     }

     /// Pointer to the underlying C++ RAMCloud object associated with this
     /// object.
     private long ramcloudObjectPointer = 0;

     /**
      * See src/RejectRules.h.
      */
     public class RejectRules {
 	private long givenVersion;
         private boolean doesntExist;
         private boolean exists;
         private boolean versionLeGiven;
         private boolean versionNeGiven;

         public RejectRules() {
             this.givenVersion = -1;
             this.exists = this.doesntExist = this.versionLeGiven = this.versionNeGiven = false;
         }

         public void setLeVersion(long version) {
             setVersion(version);
             this.versionLeGiven = true;
         }

         public void setExists() {
             this.exists = true;
         }

         public void setDoesntExists() {
             this.doesntExist = true;
         }

         public void setNeVersion(long version) {
             setVersion(version);
             this.versionNeGiven = true;
         }

         private void setVersion(long version) {
             this.givenVersion = version;
         }
     }

     public static class multiReadObject {
         long tableId;
         byte[] key;

         public multiReadObject(long _tableId, byte[] _key){
             tableId = _tableId;
             key = _key;
         }
     }

     public static class MultiWriteObject {
         long tableId;
         byte[] key;
         byte[] value;
         RejectRules rules;

         public MultiWriteObject(long tableId, byte[] key, byte[] value, RejectRules rules) {
             this.tableId = tableId;
             this.key = key;
             this.value = value;
             this.rules = rules;
         }
     }

     public class MultiWriteRspObject {
         private int status;
         private long version;

         public MultiWriteRspObject(int status, long version) {
             this.status = status;
             this.version = version;
         }
         public int getStatus() {
             return status;
         }

         public long getVersion() {
             return version;
         }
     }

     /**
      * This class is returned by Read operations. It encapsulates the entire
      * object, including the key, value, and version.
      *
      * It mostly exists because Java doesn't support primitive out parameters
      * or multiple return values, and we don't know the object's size ahead of
      * time, so passing in a fixed-length array would be problematic.
      */
     public class Object {
         Object(byte[] _key, byte[] _value, long _version)
         {
             key = _key;
             value = _value;
             version = _version;
         }

         public String
         getKey()
         {
             return new String(key);
         }

         public String
         getValue()
         {
             return new String(value);
         }

         final public byte[] key;
         final public byte[] value;
         final public long version;
     }

     public class TableEnumerator {
         private long tableEnumeratorObjectPointer = 0;
         private long ramCloudObjectPointer = 0;

         public TableEnumerator(long tableId)
         {
             ramCloudObjectPointer = ramcloudObjectPointer;
             tableEnumeratorObjectPointer = init(tableId);
         }

         private native long init(long tableId);
         public native boolean hasNext();
         public native Object next();
     }

     /**
      * Connect to the RAMCloud cluster specified by the given coordinator's
      * service locator string. This causes the JNI code to instantiate the
      * underlying RamCloud C++ object.
      */
     public
     JRamCloud(String coordinatorLocator)
     {
         ramcloudObjectPointer = connect(coordinatorLocator);
     }

     /**
      * Disconnect from the RAMCloud cluster. This causes the JNI code to
      * destroy the underlying RamCloud C++ object.
      */
     public void
     disconnect()
     {
         if (ramcloudObjectPointer != 0) {
             disconnect(ramcloudObjectPointer);
             ramcloudObjectPointer = 0;
         }
     }

     /**
      * This method is called by the garbage collector before destroying the
      * object. The user really should have called disconnect, but in case
      * they did not, be sure to clean up after them.
      */
     public void
     finalize()
     {
         System.err.println("warning: JRamCloud::disconnect() was not called " +
                            "prior to the finalizer. You should disconnect " +
                            "your JRamCloud object when you're done with it.");
         disconnect();
     }

     /**
      * Convenience read() wrapper that take a String key argument.
      */
     public Object
     read(long tableId, String key)
     {
         return read(tableId, key.getBytes());
     }

     /**
      * Convenience read() wrapper that take a String key argument.
      */
     public Object
     read(long tableId, String key, RejectRules rules)
     {
         return read(tableId, key.getBytes(), rules);
     }

     /**
      * Convenience remove() wrapper that take a String key argument.
      */
     public long
     remove(long tableId, String key)
     {
         return remove(tableId, key.getBytes());
     }

     /**
      * Convenience remove() wrapper that take a String key argument.
      */
     public long
     remove(long tableId, String key, RejectRules rules)
     {
         return remove(tableId, key.getBytes(), rules);
     }

     /**
      * Convenience write() wrapper that take String key and value arguments.
      */
     public long
     write(long tableId, String key, String value)
     {
         return write(tableId, key.getBytes(), value.getBytes());
     }

     /**
      * Convenience write() wrapper that take String key and value arguments.
      */
     public long
     write(long tableId, String key, String value, RejectRules rules)
     {
         return write(tableId, key.getBytes(), value.getBytes(), rules);
     }

     /**
      * Convenience write() wrapper that takes a String key and a byte[] value
      * argument.
      */
     public long
     write(long tableId, String key, byte[] value)
     {
         return write(tableId, key.getBytes(), value);
     }

     /**
      * Convenience write() wrapper that takes a String key and a byte[] value
      * argument.
      */
     public long
     write(long tableId, String key, byte[] value, RejectRules rules)
     {
         return write(tableId, key.getBytes(), value, rules);
     }

     private static native long connect(String coordinatorLocator);
     private static native void disconnect(long ramcloudObjectPointer);

     public native long createTable(String name);
     public native long createTable(String name, int serverSpan);
     public native void dropTable(String name);
     public native long getTableId(String name);
     public native Object read(long tableId, byte[] key);
     public native Object read(long tableId, byte[] key, RejectRules rules);
     public native Object[] multiRead(long[] tableId, byte[] keydata[], short[] keyDataSize, int requestNum);
     public native long remove(long tableId, byte[] key);
     public native long remove(long tableId, byte[] key, RejectRules rules);
     public native long write(long tableId, byte[] key, byte[] value);
     public native long write(long tableId, byte[] key, byte[] value, RejectRules rules);
     public native long writeRule(long tableId, byte[] key, byte[] value, RejectRules rules);
     public native MultiWriteRspObject[] multiWrite(MultiWriteObject[] mwrite);

     /*
      * The following exceptions may be thrown by the JNI functions:
      */

     public class TableDoesntExistException extends Exception {
         public TableDoesntExistException(String message)
         {
             super(message);
         }
     }

     public class ObjectDoesntExistException extends Exception {
         public ObjectDoesntExistException(String message)
         {
             super(message);
         }
     }

     public class ObjectExistsException extends Exception {
         public ObjectExistsException(String message)
         {
             super(message);
         }
     }

     public class WrongVersionException extends Exception {
         public WrongVersionException(String message)
         {
             super(message);
         }
     }

     public class InvalidObjectException extends Exception {
         public InvalidObjectException(String message) {
             super(message);
         }
     }

     public class RejectRulesException extends Exception {
         public RejectRulesException(String message) {
             super(message);
         }
     }

     /**
      * A simple end-to-end test of the java bindings.
      */
     public static void
     main(String argv[])
     {
         JRamCloud ramcloud = new JRamCloud(argv[0]);
         long tableId = ramcloud.createTable("hi");
         System.out.println("created table, id = " + tableId);
         long tableId2 = ramcloud.getTableId("hi");
         System.out.println("getTableId says tableId = " + tableId2);

         System.out.println("wrote obj version = " +
             ramcloud.write(tableId, "thisIsTheKey", "thisIsTheValue"));

         JRamCloud.Object o = ramcloud.read(tableId, "thisIsTheKey");
         System.out.println("read object: key = [" + o.getKey() + "], value = ["
             + o.getValue() + "], version = " + o.version);

         ramcloud.remove(tableId, "thisIsTheKey");

         try {
             ramcloud.read(tableId, "thisIsTheKey");
             System.out.println("Error: shouldn't have read successfully!");
         } catch (Exception e) {
             // OK
         }

         ramcloud.write(tableId, "thisIsTheKey", "thisIsTheValue");

         long before = System.nanoTime();
         for (int i = 0; i < 1000; i++) {
             JRamCloud.Object unused = ramcloud.read(tableId, "thisIsTheKey");
         }
         long after = System.nanoTime();
         System.out.println("Avg read latency: " +
             ((double)(after - before) / 1000 / 1000) + " usec");

         // multiRead test
         long tableId4 = ramcloud.createTable("table4");
         System.out.println("table4 id " + tableId4);
         ramcloud.write(tableId4, "object1-1", "value:1-1");
         ramcloud.write(tableId4, "object1-2", "value:1-2");
         ramcloud.write(tableId4, "object1-3", "value:1-3");
         long tableId5 = ramcloud.createTable("table5");
         System.out.println("table5 id " + tableId5);
         ramcloud.write(tableId5, "object2-1", "value:2-1");
         long tableId6 = ramcloud.createTable("table6");
         ramcloud.write(tableId6, "object3-1", "value:3-1");
         ramcloud.write(tableId6, "object3-2", "value:3-2");

 	long tableIdList[] = new long[2];
         byte[] keydata[] = new byte[2][];
         short keydataSize[] = new short[2];
         tableIdList[0] = tableId4;
         keydata[0] = "object1-1".getBytes();
         keydataSize[0] = (short) keydata[0].length;
         tableIdList[1] = tableId5;
         keydata[1] = "object2-1".getBytes();
 	keydataSize[1] = (short) keydata[1].length;

         JRamCloud.Object out[] = ramcloud.multiRead(tableIdList, keydata, keydataSize, 2);
         for (int i = 0 ; i < 2 ; i++){
             System.out.println("multi read object: key = [" + out[i].getKey() + "], value = ["
                     + out[i].getValue() + "]");
         }

         MultiWriteObject mwrite[] = new MultiWriteObject[2];
         for (int i = 0; i < 1000; i++) {
             String key1 = "key1" + new Integer(i).toString();
             String key2 = "key2" + new Integer(i).toString();

             mwrite[0] = new MultiWriteObject(tableId4, key1.getBytes(), "v0-value".getBytes(), null);
             mwrite[1] = new MultiWriteObject(tableId5, key2.getBytes(), "v1".getBytes(), null);
             MultiWriteRspObject[] rsp = ramcloud.multiWrite(mwrite);
             if (rsp != null) {
                 for (int j = 0; j < rsp.length; j++) {
                     System.out.println("multi write rsp(" + j + ") status:version " + rsp[j].getStatus() + ":" + rsp[j].getVersion());
                 }
             }
         }
         for (int i = 0; i < 1000; i++) {
             String key1 = "key1" + new Integer(i).toString();
             String key2 = "key2" + new Integer(i).toString();
             tableIdList[0] = tableId4;
             keydata[0] = key1.getBytes();
             keydataSize[0] = (short) keydata[0].length;
             tableIdList[1] = tableId5;
             keydata[1] = key2.getBytes();
             keydataSize[1] = (short) keydata[1].length;

             out = ramcloud.multiRead(tableIdList, keydata, keydataSize, 2);
             for (int j = 0; j < 2; j++) {
                 System.out.println("multi read object: key = [" + out[j].getKey() + "], value = [" + out[j].getValue() + "]");
             }
         }

         ramcloud.dropTable("table4");
         ramcloud.dropTable("table5");
         ramcloud.dropTable("table6");
         ramcloud.disconnect();
     }
 }
	/* Copyright (c) 2013 Stanford University
	*
	* Permission to use, copy, modify, and distribute this software for any
	* purpose with or without fee is hereby granted, provided that the above
	* copyright notice and this permission notice appear in all copies.
	*
	* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR(S) DISCLAIM ALL WARRANTIES
	* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
	* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL AUTHORS BE LIABLE FOR
	* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
	* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
	* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
	* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
	*/

	package edu.stanford.ramcloud;
	import java.util.ArrayList;
	import java.util.Arrays;
	import java.lang.Integer;

	/*
	* This class provides Java bindings for RAMCloud. Right now it is a rather
	* simple subset of what RamCloud.h defines.
	*
	* Running ``javah'' on this file will generate a C header file with the
	* appropriate JNI function definitions. The glue interfacing to the C++
	* RAMCloud library can be found in JRamCloud.cc.
	*
	* For JNI information, the IBM tutorials and Android developer docs are much
	* better than Sun's at giving an overall intro:
	* http://www.ibm.com/developerworks/java/tutorials/j-jni/section4.html
	* http://developer.android.com/training/articles/perf-jni.html
	*/
	public class JRamCloud {
	static {
	System.loadLibrary("edu_stanford_ramcloud_JRamCloud");
	}

	/// Pointer to the underlying C++ RAMCloud object associated with this
	/// object.
	private long ramcloudObjectPointer = 0;

	/**
	* See src/RejectRules.h.
	*/
	public class RejectRules {
	private long givenVersion;
	private boolean doesntExist;
	private boolean exists;
	private boolean versionLeGiven;
	private boolean versionNeGiven;

	public RejectRules() {
	this.givenVersion = -1;
	this.exists = this.doesntExist = this.versionLeGiven = this.versionNeGiven = false;
	}

	public void setLeVersion(long version) {
	setVersion(version);
	this.versionLeGiven = true;
	}

	public void setExists() {
	this.exists = true;
	}

	public void setDoesntExists() {
	this.doesntExist = true;
	}

	public void setNeVersion(long version) {
	setVersion(version);
	this.versionNeGiven = true;
	}

	private void setVersion(long version) {
	this.givenVersion = version;
	}
	}

	public static class multiReadObject {
	long tableId;
	byte[] key;

	public multiReadObject(long _tableId, byte[] _key){
	tableId = _tableId;
	key = _key;
	}
	}

	public static class MultiWriteObject {
	long tableId;
	byte[] key;
	byte[] value;
	RejectRules rules;

	public MultiWriteObject(long tableId, byte[] key, byte[] value, RejectRules rules) {
	this.tableId = tableId;
	this.key = key;
	this.value = value;
	this.rules = rules;
	}
	}

	public class MultiWriteRspObject {
	private int status;
	private long version;

	public MultiWriteRspObject(int status, long version) {
	this.status = status;
	this.version = version;
	}
	public int getStatus() {
	return status;
	}

	public long getVersion() {
	return version;
	}
	}

	/**
	* This class is returned by Read operations. It encapsulates the entire
	* object, including the key, value, and version.
	*
	* It mostly exists because Java doesn't support primitive out parameters
	* or multiple return values, and we don't know the object's size ahead of
	* time, so passing in a fixed-length array would be problematic.
	*/
	public class Object {
	Object(byte[] _key, byte[] _value, long _version)
	{
	key = _key;
	value = _value;
	version = _version;
	}

	public String
	getKey()
	{
	return new String(key);
	}

	public String
	getValue()
	{
	return new String(value);
	}

	final public byte[] key;
	final public byte[] value;
	final public long version;
	}

	public class TableEnumerator {
	private long tableEnumeratorObjectPointer = 0;
	private long ramCloudObjectPointer = 0;

	public TableEnumerator(long tableId)
	{
	ramCloudObjectPointer = ramcloudObjectPointer;
	tableEnumeratorObjectPointer = init(tableId);
	}

	private native long init(long tableId);
	public native boolean hasNext();
	public native Object next();
	}

	/**
	* Connect to the RAMCloud cluster specified by the given coordinator's
	* service locator string. This causes the JNI code to instantiate the
	* underlying RamCloud C++ object.
	*/
	public
	JRamCloud(String coordinatorLocator)
	{
	ramcloudObjectPointer = connect(coordinatorLocator);
	}

	/**
	* Disconnect from the RAMCloud cluster. This causes the JNI code to
	* destroy the underlying RamCloud C++ object.
	*/
	public void
	disconnect()
	{
	if (ramcloudObjectPointer != 0) {
	disconnect(ramcloudObjectPointer);
	ramcloudObjectPointer = 0;
	}
	}

	/**
	* This method is called by the garbage collector before destroying the
	* object. The user really should have called disconnect, but in case
	* they did not, be sure to clean up after them.
	*/
	public void
	finalize()
	{
	System.err.println("warning: JRamCloud::disconnect() was not called " +
	"prior to the finalizer. You should disconnect " +
	"your JRamCloud object when you're done with it.");
	disconnect();
	}

	/**
	* Convenience read() wrapper that take a String key argument.
	*/
	public Object
	read(long tableId, String key)
	{
	return read(tableId, key.getBytes());
	}

	/**
	* Convenience read() wrapper that take a String key argument.
	*/
	public Object
	read(long tableId, String key, RejectRules rules)
	{
	return read(tableId, key.getBytes(), rules);
	}

	/**
	* Convenience remove() wrapper that take a String key argument.
	*/
	public long
	remove(long tableId, String key)
	{
	return remove(tableId, key.getBytes());
	}

	/**
	* Convenience remove() wrapper that take a String key argument.
	*/
	public long
	remove(long tableId, String key, RejectRules rules)
	{
	return remove(tableId, key.getBytes(), rules);
	}

	/**
	* Convenience write() wrapper that take String key and value arguments.
	*/
	public long
	write(long tableId, String key, String value)
	{
	return write(tableId, key.getBytes(), value.getBytes());
	}

	/**
	* Convenience write() wrapper that take String key and value arguments.
	*/
	public long
	write(long tableId, String key, String value, RejectRules rules)
	{
	return write(tableId, key.getBytes(), value.getBytes(), rules);
	}

	/**
	* Convenience write() wrapper that takes a String key and a byte[] value
	* argument.
	*/
	public long
	write(long tableId, String key, byte[] value)
	{
	return write(tableId, key.getBytes(), value);
	}

	/**
	* Convenience write() wrapper that takes a String key and a byte[] value
	* argument.
	*/
	public long
	write(long tableId, String key, byte[] value, RejectRules rules)
	{
	return write(tableId, key.getBytes(), value, rules);
	}

	private static native long connect(String coordinatorLocator);
	private static native void disconnect(long ramcloudObjectPointer);

	public native long createTable(String name);
	public native long createTable(String name, int serverSpan);
	public native void dropTable(String name);
	public native long getTableId(String name);
	public native Object read(long tableId, byte[] key);
	public native Object read(long tableId, byte[] key, RejectRules rules);
	public native Object[] multiRead(long[] tableId, byte[] keydata[], short[] keyDataSize, int requestNum);
	public native long remove(long tableId, byte[] key);
	public native long remove(long tableId, byte[] key, RejectRules rules);
	public native long write(long tableId, byte[] key, byte[] value);
	public native long write(long tableId, byte[] key, byte[] value, RejectRules rules);
	public native long writeRule(long tableId, byte[] key, byte[] value, RejectRules rules);
	public native MultiWriteRspObject[] multiWrite(MultiWriteObject[] mwrite);

	/*
	* The following exceptions may be thrown by the JNI functions:
	*/

	public class TableDoesntExistException extends Exception {
	public TableDoesntExistException(String message)
	{
	super(message);
	}
	}

	public class ObjectDoesntExistException extends Exception {
	public ObjectDoesntExistException(String message)
	{
	super(message);
	}
	}

	public class ObjectExistsException extends Exception {
	public ObjectExistsException(String message)
	{
	super(message);
	}
	}

	public class WrongVersionException extends Exception {
	public WrongVersionException(String message)
	{
	super(message);
	}
	}

	public class InvalidObjectException extends Exception {
	public InvalidObjectException(String message) {
	super(message);
	}
	}

	public class RejectRulesException extends Exception {
	public RejectRulesException(String message) {
	super(message);
	}
	}

	/**
	* A simple end-to-end test of the java bindings.
	*/
	public static void
	main(String argv[])
	{
	JRamCloud ramcloud = new JRamCloud(argv[0]);
	long tableId = ramcloud.createTable("hi");
	System.out.println("created table, id = " + tableId);
	long tableId2 = ramcloud.getTableId("hi");
	System.out.println("getTableId says tableId = " + tableId2);

	System.out.println("wrote obj version = " +
	ramcloud.write(tableId, "thisIsTheKey", "thisIsTheValue"));

	JRamCloud.Object o = ramcloud.read(tableId, "thisIsTheKey");
	System.out.println("read object: key = [" + o.getKey() + "], value = ["
	+ o.getValue() + "], version = " + o.version);

	ramcloud.remove(tableId, "thisIsTheKey");

	try {
	ramcloud.read(tableId, "thisIsTheKey");
	System.out.println("Error: shouldn't have read successfully!");
	} catch (Exception e) {
	// OK
	}

	ramcloud.write(tableId, "thisIsTheKey", "thisIsTheValue");

	long before = System.nanoTime();
	for (int i = 0; i < 1000; i++) {
	JRamCloud.Object unused = ramcloud.read(tableId, "thisIsTheKey");
	}
	long after = System.nanoTime();
	System.out.println("Avg read latency: " +
	((double)(after - before) / 1000 / 1000) + " usec");

	// multiRead test
	long tableId4 = ramcloud.createTable("table4");
	System.out.println("table4 id " + tableId4);
	ramcloud.write(tableId4, "object1-1", "value:1-1");
	ramcloud.write(tableId4, "object1-2", "value:1-2");
	ramcloud.write(tableId4, "object1-3", "value:1-3");
	long tableId5 = ramcloud.createTable("table5");
	System.out.println("table5 id " + tableId5);
	ramcloud.write(tableId5, "object2-1", "value:2-1");
	long tableId6 = ramcloud.createTable("table6");
	ramcloud.write(tableId6, "object3-1", "value:3-1");
	ramcloud.write(tableId6, "object3-2", "value:3-2");

	long tableIdList[] = new long[2];
	byte[] keydata[] = new byte[2][];
	short keydataSize[] = new short[2];
	tableIdList[0] = tableId4;
	keydata[0] = "object1-1".getBytes();
	keydataSize[0] = (short) keydata[0].length;
	tableIdList[1] = tableId5;
	keydata[1] = "object2-1".getBytes();
	keydataSize[1] = (short) keydata[1].length;

	JRamCloud.Object out[] = ramcloud.multiRead(tableIdList, keydata, keydataSize, 2);
	for (int i = 0 ; i < 2 ; i++){
	System.out.println("multi read object: key = [" + out[i].getKey() + "], value = ["
	+ out[i].getValue() + "]");
	}

	MultiWriteObject mwrite[] = new MultiWriteObject[2];
	for (int i = 0; i < 1000; i++) {
	String key1 = "key1" + new Integer(i).toString();
	String key2 = "key2" + new Integer(i).toString();

	mwrite[0] = new MultiWriteObject(tableId4, key1.getBytes(), "v0-value".getBytes(), null);
	mwrite[1] = new MultiWriteObject(tableId5, key2.getBytes(), "v1".getBytes(), null);
	MultiWriteRspObject[] rsp = ramcloud.multiWrite(mwrite);
	if (rsp != null) {
	for (int j = 0; j < rsp.length; j++) {
	System.out.println("multi write rsp(" + j + ") status:version " + rsp[j].getStatus() + ":" + rsp[j].getVersion());
	}
	}
	}
	for (int i = 0; i < 1000; i++) {
	String key1 = "key1" + new Integer(i).toString();
	String key2 = "key2" + new Integer(i).toString();
	tableIdList[0] = tableId4;
	keydata[0] = key1.getBytes();
	keydataSize[0] = (short) keydata[0].length;
	tableIdList[1] = tableId5;
	keydata[1] = key2.getBytes();
	keydataSize[1] = (short) keydata[1].length;

	out = ramcloud.multiRead(tableIdList, keydata, keydataSize, 2);
	for (int j = 0; j < 2; j++) {
	System.out.println("multi read object: key = [" + out[j].getKey() + "], value = [" + out[j].getValue() + "]");
	}
	}

	ramcloud.dropTable("table4");
	ramcloud.dropTable("table5");
	ramcloud.dropTable("table6");
	ramcloud.disconnect();
	}
	}