Vic Hood

How effective is the gear addition /removal mechanism of OpenShift? I am looking to create a mini web based application , but dont really know my consumer base yet. So will Openshift scale up/down automatically?

Hello Folks,

Ive written the following code that converts a 2d arraylist into a 2d matrix, but now I need to check that the matrix created is also square(num of rows = num of columns).

Could anyone explain how I could possibly modify my code to acheive that?


My code is
int[][] input2DArray = null; ArrayList<ArrayList<Integer>> dynamicInputMatrix = new ArrayList<ArrayList<Integer>>(); try { Scanner input; input = new Scanner(new File(textFileName)); while (input.hasNextLine()) { Scanner colReader = new Scanner(input.nextLine()); ArrayList<Integer> col = new ArrayList<Integer>(); while (colReader.hasNextInt()) { col.add(colReader.nextInt()); col.trimToSize(); } dynamicInputMatrix.add(col); } input2DArray = new int[dynamicInputMatrix.size()][dynamicInputMatrix.size()]; System.out.println(input2DArray.length+" "+input2DArray[0].length); int row = 0; int column = 0; for (ArrayList<Integer> l : dynamicInputMatrix) { column = 0; while (column < l.size()) { for (Integer value : l) { if (value!=null) { input2DArray[row][column] = value; } column++; } row++; } } if (input2DArray.length!=input2DArray[0].length) { throw new IllegalStateException("The input needs to be a square matrix!"); // This code is never accessed! } } catch (FileNotFoundException e) { e.printStackTrace(); System.err.println("File not found! Please place it in the right place."); } return input2DArray; }

Im looking to learn Data Structures and their implementation . Does Think Python provide any sort of insight into them?
Thanks!

Thanks Dennis and Athira!

The problem was with not looking at the code from the right perspective. Thank you for the time!

Any help folks?!

Thanks for the reply Dennis.

I moved the if/else block into the if statement, however the program still doesnt work as expected.For instance, even if an element is actually present in the 'dotcom' , the program still results in a miss ,I some how feel that Im not being able to set the locationCells correctly in DotCom.java. Any help on that would be great.

method that sets up the Game in DotComBust
private void setupGame(){ // create Three separate Dot Com objects! DotCom one=new DotCom(); one.setName("Pets.com"); DotCom two=new DotCom(); two.setName("eToys.com"); DotCom three=new DotCom(); three.setName("MSN.com"); // Add em to the list! dotComsList.add(one); dotComsList.add(two); dotComsList.add(three); //Print out to screen. System.out.println("Your aim is to sink the three dotcoms"); System.out.println("Try to sink em in the lowest number of guesses"); // Assign the location to each of the dotcom for(DotCom dotComSet:dotComsList){ //Setting location for one dot com at a time! ArrayList<String> newLocation=helper.placeDotCom(3);// from Helper claSS! dotComSet.setLocationCells(newLocation); for(String s:newLocation){ System.out.println("Array Location"+s); } } } public String checkYourself(String userGuess){ String result="miss"; // check if there's a hit by checking for index of hit value int index=locationCells.indexOf(userGuess); System.out.println("index of"+index);// this value is always -1 , even if the arrayList contains teh element, so only misses being counted! if(index>=0){ // if hit then remove that from the list. locationCells.remove(index); if(locationCells.isEmpty()){ // once the arraylist is empty the entity has sunk result="kill"; } else{ // else mark a hit! result="hit"; } } return result; }

Result
Your aim is to sink the three dotcoms Try to sink em in the lowest number of guesses Array Locationd3 Array Locationd4 Array Locationd5 Array Locationa3 Array Locationb3 Array Locationc3 Array Locatione3 Array Locatione4 Array Locatione5 Enter a Guess! 4// this should be a hit! index of-1 index of-1 index of-1 miss ...

Hi Folks,

Im trying to learn Java through HeadFirst and tried out some of their code on my own to build a sink-a -dot-com game. The game is simple, its supposed to take three user inputs and compare them as to whether they match those of the cells alloted to the dotcoms randomly.
Here's my source code

DotComBust.java

package org.self.Test; import java.util.ArrayList; public class DotComBust { private GameHelper helper= new GameHelper(); private ArrayList<DotCom>dotComsList=new ArrayList<DotCom>(); private int numGuesses=0; private void setupGame(){ // create Three separate Dot Com objects! DotCom one=new DotCom(); one.setName("Pets.com"); DotCom two=new DotCom(); two.setName("eToys.com"); DotCom three=new DotCom(); three.setName("MSN.com"); // Add em to the list! dotComsList.add(one); dotComsList.add(two); dotComsList.add(three); //Print out to screen. System.out.println("Your aim is to sink the three dotcoms"); System.out.println("Try to sink em in the lowest number of guesses"); // Assign the location to each of the dotcom for(DotCom dotComSet:dotComsList){ //Setting location for one dot com at a time! ArrayList<String> newLocation=helper.placeDotCom(3);// from Helper claSS! dotComSet.setLocationCells(newLocation); } } private void startPlaying(){ // first check if the list is empty.If not then proceed while(!dotComsList.isEmpty()){ String userGuess=helper.getUserInput("Enter a Guess!"); //pass control to checkUserGuess checkUserGuess(userGuess); } finishGame(); } private void checkUserGuess(String userGuess){ // increment the number of guesses numGuesses++; String result="miss"; //System.out.println(result); for(DotCom dotComToTest:dotComsList){ result=dotComToTest.checkYourself(userGuess); if(result.equals("hit")){ // if hit then break; break; } if(result.equals("kill")){ dotComsList.remove(dotComToTest); break; } //print the result } System.out.println(result); } private void finishGame(){ // Method executed at end of game! System.out.println("All the Dot-coms have been sunk. Your stock is worthless!!"); if (numGuesses<=18){ System.out.println("It took you only "+numGuesses+"guesses"); System.out.println("You won before running out of options!"); } else{ System.out.println("It took you long enough"+numGuesses+"guesses"); } } public static void main(String[] args) { // TODO Auto-generated method stub DotComBust game=new DotComBust(); game.setupGame(); game.startPlaying(); } }
and DotCom.java
package org.self.Test; import java.util.ArrayList; public class DotCom { private String name; private ArrayList<String> locationCells; public void setLocationCells(ArrayList<String>loc){ locationCells=loc; } public void setName(String n){ name=n;// setter methods } public String checkYourself(String userGuess){ String result="miss"; // check if there's a hit by checking for index of hit value int index=locationCells.indexOf(userGuess); System.out.println("index of"+index); if(index>=0){ // if hit then remove that from the list. locationCells.remove(index); } if(locationCells.isEmpty()){ // once the arraylist is empty the entity has sunk result="kill"; } else{ // else mark a hit! result="hit"; } return result; } }


When I run DotComBust.java this is what happens
Your aim is to sink the three dotcoms Try to sink em in the lowest number of guesses Enter a Guess! 4 index of-1 hit Enter a Guess! 4 index of-1 hit Enter a Guess!
Im pretty sure the problem is because of the element not being present in the list, then how am I being able to print hit? Any insight would be helpful, thanks!!

Hello Budi,
First off, I have a newbie question, how different is the Servlet 3.0 spec different from the earlier spec? How different would it be to code in it, when compared to the 2.5 spec?

Finally, does the book help n00bs in handling the transition well?

Thank you and Welcome to Javaranch!

Hey Folks,
Im trying to learn a little Python but I'm curious as to how far Python could help in an Enterprise setting like Java, most of the Python Ive seen so far either tends to be for scientific application or for trying out new things.
It would be great if the authors could chip in as well.

UPDATE: Was able to fix that error. However I get the following error now

Hibernate: insert into person (NAME, SURNAME, ADDRESS) values (?, ?, ?) Hibernate: select person0_.ID as ID0_, person0_.NAME as NAME0_, person0_.SURNAME as SURNAME0_, person0_.ADDRESS as ADDRESS0_ from person person0_ Exception in thread "main" org.hibernate.exception.SQLGrammarException: could not execute query at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:92) at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66) at org.hibernate.loader.Loader.doList(Loader.java:2536) at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2276) at org.hibernate.loader.Loader.list(Loader.java:2271) at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:452) at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:363) at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196) at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1268) at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102) at com.sample.TestPerson.queryPerson(TestPerson.java:24) at com.sample.TestPerson.main(TestPerson.java:18) Caused by: org.postgresql.util.PSQLException: ERROR: column person0_.id does not exist Position: 8 at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2102) at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1835) at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:257)

What I dont understand is why is hibernate looking at person0_ instead of person, any input on this could be helpful. Thanks!

I'm trying to set up a small working sample of Hibernate that I found here.
However when I run the code I get the follwing error
.
Exception in thread "main" org.hibernate.exception.SQLGrammarException: could not insert: [com.sample.Person] at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:92) at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66) at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:64) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2345) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2852) at org.hibernate.action.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:71) at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:273) at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:320) at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:203) at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:129) at ..... Caused by: org.postgresql.util.PSQLException: ERROR: relation "person" does not exist Position: 13 at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2102) at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1835) at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:257) at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:500) at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:388) at org.postgresql.jdbc2.AbstractJdbc2Statement.executeUpdate(AbstractJdbc2Statement.java:334) at org.hibernate.id.IdentityGenerator$GetGeneratedKeysDelegate.executeAndExtract(IdentityGenerator.java:94) at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:57) ... 23 more
But I already have a table by the name person in the database and here's my hibernate.cfg.xml

<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <!-- hibernate dialect --> <property name="hibernate.dialect">org.hibernate.dialect.MySQLInnoDBDialect</property> <property name="hibernate.connection.driver_class">org.postgresql.Driver</property> <property name="hibernate.connection.url">jdbc:postgresql://localhost/testDB</property> <property name="hibernate.connection.username">postgres</property> <property name="hibernate.connection.password"></property> <property name="hibernate.show.sql" ></property> <property name="transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</property> <!-- Automatic schema creation (begin) === --> <property name="hibernate.hbm2ddl.auto">create</property> <!-- Simple memory-only cache --> <property name="hibernate.cache.provider_class">org.hibernate.cache.HashtableCacheProvider</property> <!-- Enable Hibernate's automatic session context management --> <property name="current_session_context_class">thread</property> <!-- ############################################ --> <!-- # mapping files with external dependencies # --> <!-- ############################################ --> <mapping resource="com/sample/Person.hbm.xml" /> </session-factory> </hibernate-configuration> Person.hbm.xml [code=xml] <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <hibernate-mapping> <class name="com.sample.Person" table="person"> <id name="id" column="ID"> <generator class="native" /> </id> <property name="name"> <column name="NAME" length="16" not-null="true" /> </property> <property name="surname"> <column name="SURNAME" length="16" not-null="true" /> </property> <property name="address"> <column name="ADDRESS" length="16" not-null="true" /> </property> </class> </hibernate-mapping>

Content of the postgresql log file
2012-02-13 09:23:25 IST LOG: database system was shut down at 2012-02-10 18:14:57 IST 2012-02-13 09:23:25 IST FATAL: the database system is starting up 2012-02-13 09:23:33 IST LOG: database system is ready to accept connections 2012-02-13 09:23:38 IST LOG: autovacuum launcher started 2012-02-13 09:46:01 IST ERROR: syntax error at or near "auto_increment" at character 41 2012-02-13 09:46:01 IST STATEMENT: create table person (ID bigint not null auto_increment, NAME varchar(16) not null, SURNAME varchar(16) not null, ADDRESS varchar(16) not null, primary key (ID)) type=InnoDB 2012-02-13 09:46:01 IST ERROR: relation "person" does not exist at character 13 2012-02-13 09:46:01 IST STATEMENT: insert into person (NAME, SURNAME, ADDRESS) values ($1, $2, $3) RETURNING * 2012-02-13 09:46:01 IST LOG: could not receive data from client: No connection could be made because the target machine actively refused it. 2012-02-13 09:46:01 IST LOG: unexpected EOF on client connection 2012-02-13 09:48:15 IST ERROR: syntax error at or near "auto_increment" at character 41 2012-02-13 09:48:15 IST STATEMENT: create table person (ID bigint not null auto_increment, NAME varchar(16) not null, SURNAME varchar(16) not null, ADDRESS varchar(16) not null, primary key (ID)) type=InnoDB 2012-02-13 09:48:15 IST ERROR: relation "person" does not exist at character 13 2012-02-13 09:48:15 IST STATEMENT: insert into person (NAME, SURNAME, ADDRESS) values ($1, $2, $3) RETURNING * 2012-02-13 09:48:15 IST LOG: could not receive data from client: No connection could be made because the target machine actively refused it. 2012-02-13 09:48:15 IST LOG: unexpected EOF on client connection

It would be great if anyone could point out what Im doing wrong, as this is my first attempt at Hibernate.
Thanks!

What do you mean by it doesnt work ? What exactly is the problem?

Hey Eric,
Thanks for the reply!
But what I'm worried about is whether the issue would persist, despite a change of library, like I said before, and as for the hacking, I've tried changing the z-index in the css class of the library without any respite, any suggestions?

Hi Bear, thanks for the reply, would it be advisable to use JQuery and its UI, just for the calendar functionality? The thing is the calendar control works seamlessly on other pages, but not on this one, which seems to suggest that its gotta do with the tabs in place. What if I face the same issue with JQuery as well?

As to why I chose that library, it has worked well for me so far in all the other pages that I have used so far, in far we use it across applications.

I don't know if this question has been asked before, if yes a link would do.I'm trying to use a javascript-based calendar in a webpage(jsp) that Im building with tabs. I'm using this, to help generate the tabs in my JSP, I have a few fields that require dates and hence the calendar. A snippet of what's happening when I click on the calendar, is attached below. Any help would be great, Thanks!