Tuesday, 31 May 2011

Struts 2 Starter Project for JDeveloper 11g (11.1.1.5)

I thought I would create a Struts 2 starter project (not before time) for JDeveloper 11g which included some must haves as follows to make this as close to being integrated into the IDE as possible.

  • Be able to run actions without having to alter the URL at runtime
  • Provide XML insight for struts.xml
  • View the struts.xml file from the navigator
  • Include the struts 2 tags in the component palette
Here is how I did this.

1.Create an empty project called "Web"
2. Add a HTML file called index.html, ignoring it's content for now.
3. This will give us a "public_html" directory and of course a web.xml , so at this point navigate to the file system and add the Struts 2 JAR files as follows, all these are required to "WEB-INF\lib".
  • commons-fileupload-1.2.2.jar
  • commons-logging-1.1.1.jar
  • freemarker-2.3.16.jar
  • javassist-3.11.0.GA.jar
  • ognl-3.0.1.jar
  • struts2-core-2.2.3.jar
  • xwork-core-2.2.3.jar
4. Next we have to add a struts.xml to the IDE which for Struts 2 belongs in the "WEB-INF\classes" folder. Create the folder on the file system and add a empty struts.xml file.
5. Now to view struts.xml in the navigator we have to edit the project properties and add the "WEB-INF\classes" to the project source path so it shows in the navigator as shown below.


6. From the JAR file "struts2-core-2.2.3.jar" extract the DTD "struts-2.1.7.dtd" and place it into the "WEB-INF\classes". It's the DTD which will enable XML code insight to help us build our struts 2 XML config file.
7. Refresh the project to ensure your project is starting to take shape
8. Edit struts2.xml and add content as follows, you could use code insight if you wanted to now we have that setup. You will see we reference the DTD as a SYSTEM file itself from the same directory.
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts SYSTEM "struts-2.1.7.dtd">

<struts>

    <package name="struts-demo" namespace="/" extends="struts-default">
      
      <action name="entername">
        <result>nameinput.jsp</result>
      </action>
      
      <action name="sayHello" class="pas.acs.struts.demo.actions.Hello">
        <result name="input">nameinput.jsp</result>
        <result>response.jsp</result>
      </action>
    </package>

</struts>

9. Create our action class as follows.
package pas.acs.struts.demo.actions;

import com.opensymphony.xwork2.ActionSupport;

public class Hello extends ActionSupport
{
  private String name;
  private String message;
  
  public Hello()
  {
  }

  public void setName(String name)
  {
    this.name = name;
  }

  public String getName()
  {
    return name;
  }

  public void setMessage(String message)
  {
    this.message = message;
  }

  public String getMessage()
  {
    return String.format("Hello %s", getName());
  }
}

10. Create a Hello-validation.xml to use for validation in the same directory as our class above.
<!DOCTYPE validators PUBLIC
"-//OpenSymphony Group//XWork Validator 1.0.2//EN"
"http://www.opensymphony.com/xwork/xwork-validator-1.0.2.dtd">

<validators>
  <field name="name">
    <field-validator type="requiredstring">
      <param name="trim">true</param>
      <message>Please enter name</message>
    </field-validator>
  </field>
</validators> 

11. Create the 2 required JSP as follows

nameinput.jsp
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<%@ page contentType="text/html;charset=windows-1252"%>
<%@ taglib uri="/struts-tags" prefix="s"%>
<html>
<head>
  <style type="text/css">
    .errorMessage
    {
      color:red;
    }
  </style>
  <meta http-equiv="Content-Type" content="text/html; charset=windows-1252"/>
  <title>Struts 2 Demo In JDeveloper 11g PS3</title>
</head>
<body>
  <h2>Struts 2 Demo In Jdeveloper 11g PS3</h2>
  <s:form action="sayHello" method="POST">
    <s:textfield label="Your Name" name="name" />
    <s:submit value="Go" />
  </s:form>
</body>
</html>

response.jsp
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<%@ page contentType="text/html;charset=windows-1252"%>
<%@ taglib uri="/struts-tags" prefix="s"%>
<html>
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=windows-1252"/>
  <title>Struts 2 Demo In JDeveloper 11g PS3</title>
</head>
<body>
  <h2>Struts 2 Demo In JDeveloper 11g PS3</h2>
  <s:property value="message" />
</body>
</html>

12. Edit index.html with content as follows to start our struts 2 application with the correct URL syntax to invoke the action.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
    <META HTTP-EQUIV="Refresh" CONTENT="0;URL=entername.action">
</head>

<body>
<p>Loading ...</p>
</body>
</html>

13. Edit then project properties and select "JSP tag Libraries' and then select "Add" and navigate to "struts2-core-2.2.3.jar" to find the struts tags and add them to the component palette.

14. Edit web.xml to look as follows.
<?xml version = '1.0' encoding = 'windows-1252'?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
         version="2.5" xmlns="http://java.sun.com/xml/ns/javaee">
    <filter>
        <filter-name>struts2</filter-name>
        <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
    </filter>

    <filter-mapping>
        <filter-name>struts2</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>         
</web-app>

15. Run index.html to invoke the Integrated WebLogic server and verify a page as follows.


16. Enter in your name and press the "go" button


So now you have a Struts 2 starter project for JDeveloper 11g (11.1.1.5)

Your project would look as follows within JDeveloper 11g IDE

Wednesday, 25 May 2011

Intermittent Oracle JDBC Connection Failures to RAC

More often then not I get the following come my way regarding Oracle JDBC connections to a RAC Cluster.

"My JDBC connections to a RAC cluster intermittently fail every now and then, but SQL*Plus works fine?"

Here is a little demo that will enable you to continually get JDBC connections to the RAC cluster , waiting for a connection failure. Nice way to verify if indeed there are intermittent problems from ORACLE JDBC when connecting to the cluster. We use the ScheduledExecutorService to get connections periodically and never terminate until we get a connection request failure. This demo is using an 11g R2 cluster with SCAN.

PeriodicJDBCRacTester.java (Main class to run the test)

package pas.au.jdbc.rac;

import java.io.FileInputStream;

import java.text.DateFormat;

import java.util.Date;
import java.util.Properties;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;

public class PeriodicJDBCRacTester
{
  private static final DateFormat DATEFORMAT = DateFormat.getInstance();
  private String periodString = "30";
  private String url = null;
  private String user = null;
  private String passwd = null;
  private static Properties myProperties = new Properties();
  
  public PeriodicJDBCRacTester()
  {
    try
    {
      myProperties.load(new FileInputStream("jdbcractest.properties"));
      processProps(myProperties);
    }
    catch (Exception e)
    {
      e.printStackTrace();
    }
  }
  
  public void run()
  {
    ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
    try 
    {

      LoadBalanceTest loadBalanceTest = 
         new LoadBalanceTest(url, user, passwd);

      String periodString = "30";
      int prd = Integer.parseInt(periodString);
      long period = (long) prd;
      
      System.out.println("\nPeriodic JDBC Load Balance Test ");
      System.out.println("Period to report results in seconds is : " + period + "\n");
     
      System.out.printf("** Started [%s] with %s(sec) interval between runs **\n", 
                        DATEFORMAT.format(new Date()),
                        periodString);
      
      final ScheduledFuture jdbcRacMonitor = 
          scheduler.scheduleAtFixedRate(loadBalanceTest, 0, 30, 
                                        TimeUnit.SECONDS);
                                       
              
    } 
    catch (Exception ex) 
    {
      ex.printStackTrace();
    } 
  }

  private void processProps(Properties inProps)
  {
    periodString = inProps.getProperty("period");
    url = inProps.getProperty("url");
    user = inProps.getProperty("user");
    passwd = inProps.getProperty("passwd");
  }
  
  public static void main(String[] args)
  {
    PeriodicJDBCRacTester test = new PeriodicJDBCRacTester();
    test.run();
  }
}  

LoadBalanceTest.java (Test class which is called periodically which obtains connections)
package pas.au.jdbc.rac;

import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import java.text.DateFormat;

import java.util.Date;

import oracle.jdbc.pool.OracleDataSource;

public class LoadBalanceTest implements Runnable
{
  private static final DateFormat DATEFORMAT = DateFormat.getInstance();
  
  private OracleDataSource ods = null;
  public final String userId = "scott";
  public final String password = "tiger";

  private String url = null;
  
  public LoadBalanceTest(String url, String user, String password) throws SQLException
  {
    ods = new OracleDataSource();
    ods.setUser(user);
    ods.setPassword(password);
    ods.setURL(url);  
    
    this.url = url;
    
  }

  public Connection getConnection() throws SQLException
  {
    return ods.getConnection();
  }
  
  public void run ()
  {
    Connection[] connArray = new Connection[5];
    System.out.println("\nCurrent run started at " + new Date());
    System.out.println("Obtaining 5 connections");
    try
    {
      for (int i = 0; i < connArray.length; i++)
      {
        connArray[i] = getConnection();
      }

      for (int j = 0; j < connArray.length; j++)
      {
        if (j == 0)
        {
          DatabaseMetaData meta = connArray[j].getMetaData();
          System.out.println("using URL : " + url + "\n");
          // gets driver info:

          System.out.println("=============\nDatabase Product Name is ... " +
                             meta.getDatabaseProductName());
          System.out.println("Database Product Version is  " +
                             meta.getDatabaseProductVersion());
          System.out.println("=============\nJDBC Driver Name is ........ " +
                             meta.getDriverName());
          System.out.println("JDBC Driver Version is ..... " +
                             meta.getDriverVersion());
          System.out.println("JDBC Driver Major Version is " +
                             meta.getDriverMajorVersion());
          System.out.println("JDBC Driver Minor Version is " +
                             meta.getDriverMinorVersion());
          System.out.println("=============");
        }

        getInstanceDetails(connArray[j], j);
      }

      System.out.println("Closing Connections\n");
      for (int y = 0; y < connArray.length; y++)
      {
        connArray[y].close();
      }
    }
    catch (SQLException sqle)
    {
      // TODO: Add catch code
      sqle.printStackTrace();
    }
  }

  public void getInstanceDetails (Connection conn, int i) throws SQLException
  {
    String sql = 
      "select sys_context('userenv', 'instance_name'), " + 
      "sys_context('userenv', 'server_host'), " + 
      "sys_context('userenv', 'service_name') " + 
      "from dual";
    
    Statement stmt = conn.createStatement();
    ResultSet rset = stmt.executeQuery(sql);
    while (rset.next())
    {
      System.out.println
        ("Connection #" + i + " : instance[" + rset.getString(1) + "], host[" + 
         rset.getString(2) + "], service[" + rset.getString(3) + "]");
    }
   
    stmt.close();
    rset.close();
  }
}
jdbcractest.properties (Properties file used to connect to the cluster and define the period in seconds for when the test will run)

period=30
url=jdbc:oracle:thin:@apctcsol1.au.oracle.com:1521/pas_srv
user=scott
passwd=tiger

If you want to run this with ANT you can use a build.xml as follows.
<?xml version="1.0" encoding="windows-1252" ?>

<project default="run" name="JDBCRACTester" basedir=".">

  <property file="build.properties"/>
   
  <path id="j2ee.classpath">
    <pathelement path="./lib/ojdbc6.jar"/>
    <pathelement path="./lib/JDBCRACTester.jar"/>
  </path>

  <property name="src.dir" value="src"/>
  <property name="classes.dir" value="classes"/>
  <property name="lib.dir" value="lib"/>
  <property name="class.name" value="pas.au.jdbc.rac.PeriodicJDBCRacTester"/>
  
  <target name="init">
    <tstamp/>
    <mkdir dir="${lib.dir}"/>
    <mkdir dir="${classes.dir}"/>
  </target>
  
  <target name="clean" description="Clean lib, classes directories">
    <delete dir="${classes.dir}"/>
  </target>
  
  <target name="compile" description="Compiles classes into ${classes.dir}" depends="init">
    <javac includeantruntime="false" srcdir="${src.dir}" debug="true" destdir="${classes.dir}" 
           includes="**/*.java" >
      <classpath refid="j2ee.classpath"/>
    </javac>
  </target>

  <target name="package" depends="compile" description="Package application into ${ant.project.name}.jar">
    <jar basedir="${classes.dir}" destfile="${lib.dir}/${ant.project.name}.jar">
      <include name="**/*.class"/>
    </jar>
  </target>
  
  <target name="run" depends="package" description="Run the JDBC RAC Tester application">
    <echo message="Running the JDBC RAC Tester application"/>
    <java classname="${class.name}" fork="true">
      <classpath>
        <path refid="j2ee.classpath"/>
        <path path="${lib.dir}/${ant.project.name}.jar"/>
      </classpath>
    </java>
  </target>

</project>

Output (Run using ANT) 

  run:
     [echo] Running the JDBC RAC Tester application
     [java]
     [java] Periodic JDBC Load Balance Test
     [java] Period to report results in seconds is : 30
     [java]
     [java] ** Started [5/25/11 9:38 AM] with 30(sec) interval between runs **
     [java]
     [java] Current run started at Wed May 25 09:38:59 EST 2011
     [java] Obtaining 5 connections
     [java] using URL : jdbc:oracle:thin:@apctcsol1.au.oracle.com:1521/pas_srv
     [java]
     [java] =============
     [java] Database Product Name is ... Oracle
     [java] Database Product Version is  Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - Production
     [java] With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
     [java] Data Mining and Real Application Testing options
     [java] =============
     [java] JDBC Driver Name is ........ Oracle JDBC driver
     [java] JDBC Driver Version is ..... 11.2.0.2.0
     [java] JDBC Driver Major Version is 11
     [java] JDBC Driver Minor Version is 2
     [java] =============
     [java] Connection #0 : instance[A12], host[auw2k4], service[pas_srv]
     [java] Connection #1 : instance[A11], host[auw2k3], service[pas_srv]
     [java] Connection #2 : instance[A12], host[auw2k4], service[pas_srv]
     [java] Connection #3 : instance[A11], host[auw2k3], service[pas_srv]
     [java] Connection #4 : instance[A12], host[auw2k4], service[pas_srv]
     [java] Closing Connections
     [java]
     [java]
     [java] Current run started at Wed May 25 09:39:29 EST 2011
     [java] Obtaining 5 connections
     [java] using URL : jdbc:oracle:thin:@apctcsol1.au.oracle.com:1521/pas_srv
     [java]
     [java] =============
     [java] Database Product Name is ... Oracle
     [java] Database Product Version is  Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - Production
     [java] With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
     [java] Data Mining and Real Application Testing options
     [java] =============
     [java] JDBC Driver Name is ........ Oracle JDBC driver
     [java] JDBC Driver Version is ..... 11.2.0.2.0
     [java] JDBC Driver Major Version is 11
     [java] JDBC Driver Minor Version is 2
     [java] =============
     [java] Connection #0 : instance[A12], host[auw2k4], service[pas_srv]
     [java] Connection #1 : instance[A11], host[auw2k3], service[pas_srv]
     [java] Connection #2 : instance[A12], host[auw2k4], service[pas_srv]
     [java] Connection #3 : instance[A11], host[auw2k3], service[pas_srv]
     [java] Connection #4 : instance[A11], host[auw2k3], service[pas_srv]
     [java] Closing Connections
     [java]

Thursday, 5 May 2011

How to Access Oracle Coherence Caches from a JRuby App

The following how to shows how to access the Coherence Grid using JRuby as an extend client. Easy to setup and run using ANT.

http://www.oracle.com/technetwork/articles/dsl/jruby-coherence-393993.html