Latest topics for the forum "Docs"

Yale Football Coach Resigns After Faulty Rhodes Scholarship Claim

shoud7 — GMT

NEW HAVEN, Conn. -- Yale football coach Tom Williams resigned Wednesday amid a probe by the university into whether he lied on his resume about being a candidate for a prestigious Rhodes scholarship, the New Haven Register reported.
Williams said last month that when he was a senior linebacker at Stanford in 1992 he was a candidate for a Rhodes scholarship, but passed up the opportunity in favor of an NFL tryout.
He spoke on the issue while Yale quarterback Patrick Witt, a Rhodes finalist, debated whether to play in the season finale against archrival Harvard or miss the game for an interview that would determine if he obtained the scholarship.

Witt opted to play in the Nov. 19 game, which Yale lost 45-7.
Williams, who turns 42 Thursday, listed on his resume submitted to Yale that he had been a Rhodes finalist.
The university launched an inquiry after The New York Times reported that the Rhodes Trust, which finances the scholarship, had no record of Williams ever applying for the scholarship.
The result of the inquiry has not been made public. Williams, in a statement announcing his decision, sought to explain the discrepancy.

Database Replication

saoj — GMT

We know that it is impossible to abandon your good and old relational database. You will probably need to do offline reports and heavy queries and a relational database is perfect for that. So what you need is to replicate all your Space4J commands to a relational database. To do this you can implement the executeSQL method for your commands so that you can later read the logs and execute them against a relational database.

Check the method below from the [i]Command [/i]interface:

[code]
/**
* This method will let you replicate your data in a relational database,
* so you can continue creating your reports and using data data warehousing tools with SQL.
* Doing this with Space4J and Commands is possible, but not recommended at all.
* Note that this method is not abstract, therefore it is not required.
* It is up to the system to replicate its data in a relational database.
* Rodolfo de Paula was the first one to raise this issue! Why not have the best of both worlds?
* @param conn A connection to the database where this command will be executed through SQL.
* @throws SQLException If there was an error executing the SQL.
*/
public void executeSQL(Connection conn) throws SQLException {}
[/code]

[u]ToDo:[/u] Create a standalone program that read the logs and execute them against a JDBC connection.

Clustering

saoj — GMT

Clustering can be useful for load-balance and fault-tolerance. It also allows a snapshot to be taken without placing the whole system in read-only mode. That's because you can use a slave to take snapshot while the rest of the nodes continue to run like nothing as happened, in other words, only the slave taking the snapshot needs to enter read-only mode.

To create a Space4J cluster is very easy and simple. Refer to the [url="http://www.space4j.org/phonebookcluster.jsp"]PhoneBookCluster.java[/url] program for an example. We also have a [url="http://s4j.mentaframework.org/posts/list/4.page"]stress program[/url] to test the cluster feature.

The source code for PhoneBookCluster.java is below:
[code]
package org.space4j.examples.phonebook;

import org.space4j.Space4J;
import org.space4j.implementation.MasterSpace4J;
import org.space4j.implementation.SlaveSpace4J;

/**
* This is to show you how simple it is to make a Space4J cluster!
*
* To make a cluster, open up two shells (or DOS) and execute in the first:
*
* java org.space4j.demos.phonebook.PhoneBookCluster master
*
* and in the second:
*
* java org.space4j.demos.PhoneBookCluster slave 127.0.0.1
*
* You can also use two different machines. Just pass the master IP address to the slave instead of 127.0.0.1.
* IMPORTANT: If you use two different machines, you must have the main Space4J dir (space4j_db) mounted, so
* both machines can have access to it.
*/
public class PhoneBookCluster extends PhoneBookIndexing {

public PhoneBookCluster(Space4J space4j) throws Exception {

super(space4j);

}

static Space4J createSpace4J(String master, String master_ip) throws Exception {

Space4J space4j = null;

if (master.equals("-master")) {

space4j = new MasterSpace4J("PhoneBook");

} else if (master.equals("-slave")) {

if (master_ip != null) {

space4j = new SlaveSpace4J("PhoneBook", master_ip);

} else {

space4j = new SlaveSpace4J("PhoneBook", "127.0.0.1");

}
}

return space4j;
}

public static void main(String[] args) throws Exception {

if (args.length < 1 || args.length > 2) {

System.out.println(
"format: java PhoneBookCluster [-master|-slave] ");

return;
}

Space4J space4j = createSpace4J(args[0],
args.length > 1 ? args[1] : null);

PhoneBookCluster book = new PhoneBookCluster(space4j);

run(book);
}
}
[/code]

Indexing

saoj — GMT

When your collection becomes too big, even in-memory searches can become expensive. Imagine a Java collection with 1 million users and you need to find all users with the last name equals to "Smith". Iterating through all elements is clearly not an option. What you need is INDEXES.

Space4J supports 4 different types of indexes through maps, in other words, when you create an index a new Java Map is created to store the index.

The four types of index are:

:arrow: Index.TYPE.REGULAR = Unique index non-sorted. This is used to get an user by its id for example, where each user has an unique id.
[code]
User u = usersById.get(2345);
[/code]

:arrow: Index.TYPE.SORTED = Unique index sorted. This is used to get a list of users in a range of ids (ex: 4000 < id < 5000). Also used when you need to fetch users sorted by the indexed field.
[code]
Map map = usersById.subMap(4000, 5000);

// or to get all the values

Collection users = usersById.subMap(4000, 5000).values();
[/code]

:arrow: Index.TYPE.MULTI = Non-unique index non-sorted. This is used to get all users with age equal to 23.
[code]
Set users = usersByAge.get(23);
[/code]

:arrow: Index.TYPE.MULT_SORTED = Non-unique index sorted. This is used to get all users with age >= 23 and age <= 40. Also used when you need to fech users sorted by the indexed field.
[code]
Map> map = usersByAge.subMap(23, 40);

// or to get a collection with all the values

Collection users = usersByAge.subMapValues(23, 40);
[/code]

The [url="http://www.space4j.org/phonebookindex.jsp"]PhoneBookIndexing.java[/url] program provides examples of how to create and user indexes for your collections in memory. Below is the source code:
[code]
package org.space4j.examples.phonebook;

import java.util.Collection;

import org.space4j.Space4J;
import org.space4j.implementation.SimpleSpace4J;
import org.space4j.indexing.Index;
import org.space4j.indexing.IndexManager;
import org.space4j.indexing.Key;
import org.space4j.indexing.MultiMap;
import org.space4j.indexing.MultiSortedMap;

public class PhoneBookIndexing extends PhoneBook {

private static final String INDX_LASTNAME = "indx_lastname";

private static final String INDX_AGE = "indx_age";

private final Index indexByLastName;

private final Index indexByAge;

public PhoneBookIndexing(Space4J space4j) throws Exception {

super(space4j);

IndexManager im = space.getIndexManager();

// If index does not exist, let's create it...
if (!im.checkIndex(INDX_LASTNAME)) {

/*
* Index name = INDX_LASTNAME
* Map in the Space that will be indexed = MAP_NAME
* Type of index = MULTI = non-unique index
* Object that will be indexed = User.class
* Atributes of the object that will be indexed = "lastName"
*
* We want to create this index because we will be searching
* for Users by lastName. We don't want to do a full table
* scan anymore like in the example without indexes.
*/

Index indx = new Index(INDX_LASTNAME, MAP_NAME, Index.TYPE.MULTI, User.class, "lastName");

boolean ok = im.createIndex(indx, space4j);

if (ok) {

System.out.println(indx + " created!");

} else {

System.out.println(indx + " could not be created!");
}
}

// If index does not exist, let's create it...
if (!im.checkIndex(INDX_AGE)) {

/*
* Index name = INDX_AGE
* Map in the Space that will be indexed = MAP_NAME
* Type of index = MULTI = non-unique sorted index
* Object that will be indexed = User.class
* Atributes of the object that will be indexed = "age"
*
* We want to create this index because we will be searching
* for Users by age. The index will be SORTED because we want
* to search for users in a age range. (age > min and age < max)
*/

Index indx = new Index(INDX_AGE, MAP_NAME, Index.TYPE.MULTI_SORTED, User.class, "age");

boolean ok = im.createIndex(indx, space4j);

if (ok) {

System.out.println(indx + " created!");

} else {

System.out.println(indx + " could not be created!");
}
}

indexByLastName = im.getIndex(INDX_LASTNAME);
indexByAge = im.getIndex(INDX_AGE);
}

/*
* Let's override our search method to use our
* index instead of doing a full table scan.
*/
@Override
public Collection findUsers(String last) {

// Remember that our index is of the type MULTI.

MultiMap map = indexByLastName.getMap();

// A multi-map will store a Set for each key.
// That's why our index is NON-UNIQUE meaning the same
// key (lastName) can be associated with different entries in the map.
// That makes sense as some users can have the same last name.

return map.get(last);
}

@Override
public Collection findUsers(int minAge, int maxAge) {

// Remember that our index is of the type MULTI_SORTED.

MultiSortedMap map = indexByAge.getMap();

// A multi-sorted-map will store a Set for each key.
// That's why our index is NON-UNIQUE meaning the same
// key (minAge, maxAge) can be associated with different entries in the map.
// The map is also sorted by its key, meaning we can
// perform range searches efficiently like below.

return map.subMapValues(new Key(minAge), true, new Key(maxAge), true);
}

public static void main(String[] args) throws Exception {

PhoneBookIndexing book = new PhoneBookIndexing(
new SimpleSpace4J("PhoneBook"));

run(book);

}
}
[/code]

Cluster Stress Test

saoj — GMT

To stress test Space4J's cluster implementation, let's place a master node and a slave node under stress doing many reads and updates. Each node will have a predefined number of threads doing insert, delete, search and iteration at the same time in the Java collection in memory. A snapshot will also be taken from time to time by the slave node.

You can download the [i]PhoneBookClusterStress.java[/i] program by [url="http://www.space4j.org/examples/PhoneBookClusterStress.java"]clicking here[/url]. The source code is also listed below. (Note that to compile and run this problem you must include the space4.jar in the classpath)

To run this example you need to open two shell/dos windows, one for the master node and one for the slave node. You can also run each node in a separate machine over the network.

The arguments you must pass to the each program are:

:arrow: -master or -slave = to indicate if this node is the master or the slave
:arrow: IP address of the master
:arrow: number of insert threads
:arrow: number of delete threads
:arrow: number of select threads
:arrow: number of search threads
:arrow: thread sleep time = how long each thread will sleep after each action
:arrow: collection initial size = how many elements should the collection has before the threads start
:arrow: snapshot time = how often should we take a snapshot

After executing the programs for some time, hit CTRL+C to print the statistics. Here is an example:

[u]Master Program:[/u]
[code]
java -cp .;space4j.jar org.space4j.examples.phonebook.PhoneBookClusterStress -master 127.0.0.1 5 4 10 5 50 2000 1000
...
...
...
Selected 302 records!
Found 14 recods!
Selected 302 records!
Selected 302 records!
Selected 302 records!
Selected 302 records!
Selected 302 records!
Found 24 recods!
Found 21 recods!
Found 23 recods!
Selected 302 records!
Selected 302 records!
Inserted record number 5004
Inserted record number 5005
Deleted record number 2489
Inserted record number 5006
Deleted record number 4974
Deleted record number 655
Deleted record number 4926
Inserted record number 5007

========== Results:
Inserted = 2487
Deleted = 2041
Selected = 2334460
Searched = 86698
Snapshots= 0
Time: 39265 ms
[/code]
[u]Slave Program:[/u]
[code]
java -cp .;space4j.jar org.space4j.examples.phonebook.PhoneBookClusterStress -slave 127.0.0.1 5 4 10 5 50 2000 1000
...
...
Inserted record number 13273
Deleted record number 3267
Deleted record number 6578
Found 31 recods!
Selected 302 records!
Selected 302 records!
Selected 302 records!
Found 28 recods!
Selected 302 records!
Selected 302 records!
Found 41 recods!
Selected 302 records!
Found 24 recods!
Selected 302 records!
Selected 302 records!
Selected 302 records!
Found 29 recods!
Selected 302 records!
Executing snapshot...
=============================> Snapshot Complete!

========== Results:
Inserted = 30
Deleted = 32
Selected = 45300
Searched = 2558
Snapshots= 3
Time: 781 ms

[/code]
The source code of the [i]PhoneBookClusterStress.java[/i] program:
[code]
package org.space4j.examples.phonebook;

import java.util.Collection;
import java.util.Iterator;
import java.util.Random;

import org.space4j.Space4J;

public class PhoneBookClusterStress extends PhoneBookCluster {

private final Thread[] insertThread;

private final Thread[] deleteThread;

private final Thread[] selectThread;

private final Thread[] searchThread;

private Thread snapshotThread;

private Random rand = new Random();

private volatile long totalInserted = 0;
private volatile long totalDeleted = 0;
private volatile long totalSelected = 0;
private volatile long totalSearched = 0;
private volatile long snapshotsTaken = 0;

private long started;

private volatile boolean running = true;

public PhoneBookClusterStress(Space4J space4j, final int nInsert, final int nDelete, final int nSelect, final int nSearch,
final int sleepTime, final int tableSize, final int snapshotTime) throws Exception {

super(space4j);

// populate the table if needed...

int size = users.size();

if (size < tableSize) {

int diff = tableSize - size;

for (int i = 0; i < diff; i++) {

insertRandom();

System.out.print("\rInserting " + i + "... ");
}
}

System.out.println();

insertThread = new Thread[nInsert];

deleteThread = new Thread[nDelete];

selectThread = new Thread[nSelect];

searchThread = new Thread[nSearch];

for (int i = 0; i < nInsert; i++) {
insertThread[i] = new Thread(new Runnable() {

public void run() {

while (running) {

try {

Thread.sleep(sleepTime);

handleInsert();

} catch (Exception e) {

return;
}
}
}

});
}

for (int i = 0; i < nDelete; i++) {
deleteThread[i] = new Thread(new Runnable() {

public void run() {

while (running) {

try {

Thread.sleep(sleepTime);

handleDelete();

} catch (Exception e) {

return;
}
}
}

});
}

for (int i = 0; i < nSelect; i++) {
selectThread[i] = new Thread(new Runnable() {

public void run() {

while (running) {

try {

Thread.sleep(sleepTime);

handleSelect();

} catch (Exception e) {

return;
}
}
}

});
}

for (int i = 0; i < nSearch; i++) {
searchThread[i] = new Thread(new Runnable() {

public void run() {

while (running) {

try {

Thread.sleep(sleepTime);

handleSearch();

} catch (Exception e) {

return;
}
}
}

});
}

if (snapshotTime > 0) {

snapshotThread = new Thread(
new Runnable() {

public void run() {

while (running) {

try {

Thread.sleep(snapshotTime);

System.out.println("Executing snapshot...");

PhoneBookClusterStress.this.executeSnapshot();

System.out.println(
"=============================> Snapshot Complete!");

snapshotsTaken++;

} catch (Exception e) {

return;
}
}
}

});
}
}

public void start() {

for (int i = 0; i < insertThread.length; i++) {
insertThread[i].start();
}

for (int i = 0; i < deleteThread.length; i++) {
deleteThread[i].start();
}

for (int i = 0; i < selectThread.length; i++) {
selectThread[i].start();
}

for (int i = 0; i < searchThread.length; i++) {
searchThread[i].start();
}

snapshotThread.start();
}

protected int insertRandom() throws Exception {

// insert a random phone number...

StringBuilder sb = new StringBuilder();

sb.append("Oliveira").append(rand.nextInt(100) + 1);

return this.addNumber("Sergio", sb.toString(), "123-4321", rand.nextInt(100) + 1);
}

protected int deleteRandom() throws Exception {

// delete a random phone number
// (guess a number, iterate to choose a phone and delete it)

Iterator iter = users.keySet().iterator();

int count = rand.nextInt(users.size() / 10) + 1;

int index = 0;

int id = -1;

while (iter.hasNext() && index++ <= count) {

id = (Integer) iter.next();

}

if (id > 0) {

this.delUser(id);

}

return id;
}

private void handleInsert() throws Exception {

int id = insertRandom();

System.out.println("Inserted record number " + id);

totalInserted++;
}

private void handleDelete() throws Exception {

int id = deleteRandom();

if (id == -1) {

System.out.println("Could not delete anything!");

} else {

System.out.println("Deleted record number " + id);

totalDeleted++;
}
}

private void handleSelect() {

// select any 300 phone numbers and loop through them...

Iterator iter = users.values().iterator();

int count = 0;

while (iter.hasNext() && count++ <= 300) {

iter.next();
}

System.out.println("Selected " + count + " records!");

totalSelected += count;
}

private void handleSearch() {

// choose a user and try to find his phone number...

StringBuilder sb= new StringBuilder();

sb.append("Oliveira").append(rand.nextInt(100) + 1);

Collection coll = this.findUsers(sb.toString());

int count = 0;

Iterator iter = coll.iterator();

while (iter.hasNext()) {

count++;

iter.next();
}

System.out.println("Found " + count + " recods!");

totalSearched += count;

}

private void interruptAll() {

for(int i=0;i

for(int i=0;i

for(int i=0;i

for(int i=0;i
}

public static void main(String[] args) throws Exception {

if (args.length >= 3) {

if (args[2].equals("-nostress")) {

Space4J space4j = createSpace4J(args[0], args[1]);

PhoneBookCluster phone = new PhoneBookCluster(space4j);

run(phone);

return;
}

}

if (args.length != 9) {

System.out.println(
"format: java PhoneBookClusterStress [-master|-slave] [-nostress] "
+ " ");

return;
}

int nInsert, nDelete, nSelect, nSearch, sleepTime, tableSize, snapTime;

nInsert = Integer.parseInt(args[2]);

nDelete = Integer.parseInt(args[3]);

nSelect = Integer.parseInt(args[4]);

nSearch = Integer.parseInt(args[5]);

sleepTime = Integer.parseInt(args[6]);

tableSize = Integer.parseInt(args[7]);

snapTime = Integer.parseInt(args[8]);

// let the slaves take the snapshot
if (args[0].equals("-master")) {
snapTime = 0;
}

Space4J space4j = createSpace4J(args[0], args[1]);

final PhoneBookClusterStress stress = new PhoneBookClusterStress(space4j,
nInsert, nDelete, nSelect, nSearch, sleepTime, tableSize,
snapTime);

stress.started = System.currentTimeMillis();

Runtime.getRuntime().addShutdownHook(new Thread() {

@Override
public void run() {

long totalInserted = stress.totalInserted;
long totalDeleted = stress.totalDeleted;
long totalSelected = stress.totalSelected;
long totalSearched = stress.totalSearched;
long snapshotsTaken = stress.snapshotsTaken;
long now = System.currentTimeMillis();

stress.running = false;

stress.interruptAll();

try { Thread.sleep(1500); } catch(Exception e) { }

System.out.println("\n\n========== Results:");
System.out.println("Inserted = " + totalInserted);
System.out.println("Deleted = " + totalDeleted);
System.out.println("Selected = " + totalSelected);
System.out.println("Searched = " + totalSearched);
System.out.println("Snashopts= " + snapshotsTaken);
System.out.println("Time: " + (now - stress.started) + " ms");

}
});

stress.start();
}

}
[/code]

Stress Test

saoj — GMT

To prove how fast and highly multithreaded Space4J is, we implemented a stress test program that creates many threads to perform insertion, deletion, search and iteration at the same time in the same indexed Java collection in memory.

You can download the [i]PhoneBookStress.java[/i] program by [url="http://www.space4j.org/examples/PhoneBookStress.java"]clicking here[/url]. The source code is also listed below. (Note that to compile and run this problem you must include the space4.jar in the classpath)

The arguments you must pass to the program are:

:arrow: number of insert threads
:arrow: number of delete threads
:arrow: number of select threads
:arrow: number of search threads
:arrow: thread sleep time = how long each thread will sleep after each action
:arrow: collection initial size = how many elements should the collection has before the threads start
:arrow: snapshot time = how often should we take a snapshot

After executing the program for some time, hit CTRL+C to print the statistics. Here is an example:
[code]
java -cp .;space4j.jar org.space4j.examples.phonebook.PhoneBookStress 5 4 10 5 50 2000 1000
...
...
...
Found 29 recods!
Found 28 recods!
Found 27 recods!
Selected 302 records!
Selected 302 records!
Found 20 recods!
Selected 302 records!
Found 22 recods!
=============================> Snapshot Complete!
Deleted record number 575
Deleted record number 1224
Deleted record number 675
Inserted record number 3020
Inserted record number 3019
Inserted record number 3018
Deleted record number 575
Inserted record number 3017
Inserted record number 3021

========== Results:
Inserted = 60
Deleted = 54
Selected = 79426
Searched = 2867
Snapshots=6
Time: 1375 ms
[/code]

The source code of the [i]PhoneBookStress.java[/i] program:
[code]
package org.space4j.examples.phonebook;

import java.util.Collection;
import java.util.Iterator;
import java.util.Random;

import org.space4j.Space4J;
import org.space4j.implementation.SimpleSpace4J;

public class PhoneBookStress extends PhoneBookIndexing {

private final Thread[] insertThread;

private final Thread[] deleteThread;

private final Thread[] selectThread;

private final Thread[] searchThread;

private final Thread snapshotThread;

private Random rand = new Random();

private volatile long totalInserted = 0;
private volatile long totalDeleted = 0;
private volatile long totalSelected = 0;
private volatile long totalSearched = 0;
private volatile long snapshotsTaken = 0;

private long started;

private volatile boolean running = true;

public PhoneBookStress(Space4J space4j, final int nInsert, final int nDelete, final int nSelect, final int nSearch,
final int sleepTime, final int tableSize, final int snapshotTime) throws Exception {

super(space4j);

// populate the table if needed...

int size = users.size();

if (size < tableSize) {

int diff = tableSize - size;

for (int i = 0; i < diff; i++) {

insertRandom();

System.out.print("\rInserting " + i + "... ");
}
}

System.out.println();

insertThread = new Thread[nInsert];

deleteThread = new Thread[nDelete];

selectThread = new Thread[nSelect];

searchThread = new Thread[nSearch];

for (int i = 0; i < nInsert; i++) {
insertThread[i] = new Thread(new Runnable() {

public void run() {

while (running) {

try {

Thread.sleep(sleepTime);

handleInsert();

} catch (Exception e) {

return;
}
}
}

});
}

for (int i = 0; i < nDelete; i++) {
deleteThread[i] = new Thread(new Runnable() {

public void run() {

while (running) {

try {

Thread.sleep(sleepTime);

handleDelete();

} catch (Exception e) {

return;
}
}
}

});
}

for (int i = 0; i < nSelect; i++) {
selectThread[i] = new Thread(new Runnable() {

public void run() {

while (running) {

try {

Thread.sleep(sleepTime);

handleSelect();

} catch (Exception e) {

return;
}
}
}

});
}

for (int i = 0; i < nSearch; i++) {
searchThread[i] = new Thread(new Runnable() {

public void run() {

while (running) {

try {

Thread.sleep(sleepTime);

handleSearch();

} catch (Exception e) {

return;
}
}
}

});
}

snapshotThread = new Thread(
new Runnable() {

public void run() {

while (running) {

try {

Thread.sleep(snapshotTime);

System.out.println("Executing snapshot...");

PhoneBookStress.this.executeSnapshot();

System.out.println(
"=============================> Snapshot Complete!");

snapshotsTaken++;

} catch (Exception e) {

return;
}
}
}

});
}

public void start() {

for (int i = 0; i < insertThread.length; i++) {
insertThread[i].start();
}

for (int i = 0; i < deleteThread.length; i++) {
deleteThread[i].start();
}

for (int i = 0; i < selectThread.length; i++) {
selectThread[i].start();
}

for (int i = 0; i < searchThread.length; i++) {
searchThread[i].start();
}

snapshotThread.start();
}

protected int insertRandom() throws Exception {

// insert a random phone number...

StringBuilder sb = new StringBuilder();

sb.append("Oliveira").append(rand.nextInt(100) + 1);

return this.addNumber("Sergio", sb.toString(), "123-4321", rand.nextInt(100) + 1);
}

protected int deleteRandom() throws Exception {

// delete a random phone number
// (guess a number, iterate to choose a phone and delete it)

Iterator iter = users.keySet().iterator();

int count = rand.nextInt(users.size() / 10) + 1;

int index = 0;

int id = -1;

while (iter.hasNext() && index++ <= count) {

id = (Integer) iter.next();

}

if (id > 0) {

this.delUser(id);

}

return id;
}

private void handleInsert() throws Exception {

int id = insertRandom();

System.out.println("Inserted record number " + id);

totalInserted++;
}

private void handleDelete() throws Exception {

int id = deleteRandom();

if (id == -1) {

System.out.println("Could not delete anything!");

} else {

System.out.println("Deleted record number " + id);

totalDeleted++;
}
}

private void handleSelect() {

// select any 300 phone numbers and loop through them...

Iterator iter = users.values().iterator();

int count = 0;

while (iter.hasNext() && count++ <= 300) {

iter.next();
}

System.out.println("Selected " + count + " records!");

totalSelected += count;
}

private void handleSearch() {

// choose a user and try to find his phone number...

StringBuilder sb= new StringBuilder();

sb.append("Oliveira").append(rand.nextInt(100) + 1);

Collection coll = this.findUsers(sb.toString());

int count = 0;

Iterator iter = coll.iterator();

while (iter.hasNext()) {

count++;

iter.next();
}

System.out.println("Found " + count + " recods!");

totalSearched += count;

}

private void interruptAll() {

for(int i=0;i

for(int i=0;i

for(int i=0;i

for(int i=0;i
}

public static void main(String[] args) throws Exception {

if (args.length >= 1) {

if (args[0].equals("-nostress")) {

PhoneBook book = new PhoneBook(new SimpleSpace4J("PhoneBook"));

run(book);

return;
}

}

if (args.length != 7) {

System.out.println(
"format: java PhoneBookStress [-nostress] "
+ " ");

return;
}

int nInsert, nDelete, nSelect, nSearch, sleepTime, tableSize, snapTime;

nInsert = Integer.parseInt(args[0]);

nDelete = Integer.parseInt(args[1]);

nSelect = Integer.parseInt(args[2]);

nSearch = Integer.parseInt(args[3]);

sleepTime = Integer.parseInt(args[4]);

tableSize = Integer.parseInt(args[5]);

snapTime = Integer.parseInt(args[6]);

final PhoneBookStress stress = new PhoneBookStress(
new SimpleSpace4J("PhoneBook"), nInsert, nDelete, nSelect,
nSearch, sleepTime, tableSize, snapTime);

stress.started = System.currentTimeMillis();

Runtime.getRuntime().addShutdownHook(new Thread() {

@Override
public void run() {

long totalInserted = stress.totalInserted;
long totalDeleted = stress.totalDeleted;
long totalSelected = stress.totalSelected;
long totalSearched = stress.totalSearched;
long snapshotsTaken = stress.snapshotsTaken;
long now = System.currentTimeMillis();

stress.running = false;

stress.interruptAll();

try { Thread.sleep(1500); } catch(Exception e) { }

System.out.println("\n\n========== Results:");
System.out.println("Inserted = " + totalInserted);
System.out.println("Deleted = " + totalDeleted);
System.out.println("Selected = " + totalSelected);
System.out.println("Searched = " + totalSearched);
System.out.println("Snashopts= " + snapshotsTaken);
System.out.println("Time: " + (now - stress.started) + " ms");

}
});

stress.start();
}

}

[/code]