Writing a Simple Java Application

Using the DAS Java API is very easy. Below we will describe the steps needed to create a simple job application.

Step 1: Write the Source Code

Copy the code listed below into the a text file named SimpleJob.java.

import java.io.*;

import java.lang.*;

import ecrion.das.*;

import java.net.*;

import java.util.*;

public class SampleJob

{

public static void main(String[] args)

{

try

{

// create parameters

JobParameters rp = new JobParameters();

// create a new engine

Engine eng = new Engine();

//Make sure that this path is valid!!!

String jobPath = "C:\\Users\\Public\\Documents\\Ecrion\\Data Aggregation Server 2011\\Samples\\Job Samples\\SampleCSV.dax";

rp.Diagram = new LocalDiagram(jobPath);

//Make sure that this path is valid!!

String csvPath = "C:\\Users\Public\\Documents\\Ecrion\\Data Aggregation Server 2011\\Samples\\Database Samples\\US Presidents.csv");

//override CSV file path

rp.Diagram.Properties = new Vector();

rp.Diagram.Properties.add(new JobProperty("11", "src", csvPath));

// create an output stream

OutputStream outputStream = new FileOutputStream("C:\\Temp\\CSVSample.xml");

// render

eng.Aggregate(outputStream, rp);

// remember to close the streams

inputStream.close();

outputStream.close();

}

catch(Exception e)

{

System.out.println(e.getMessage());

};

}

Step 2: Compile the Code File

First locate our .jar file named Ecrion.DAS.Java.jar. It should be in C:\Program Files\Ecrion\Data Aggregation Server 2011\Client\Java or C:\Program Files (x86)\Ecrion\Data Aggregation Server 2011\Client\Java under a default installation. We'll assume that this is the case and provide the console commands under this assumption. If you have the .jar under a different path you can adapt the commands to use that location. Also make sure that you have the Java Development Kit installed. To check, search for a directory under C:\Program Files\Java that starts with the string "jdk".

Open a console, navigate using the cd command to the location where you saved your SimpleJob.java file and type the following:

> javac -cp ".;C:\Program Files\Ecrion\Data Aggregation Server 2011\Client\Java\Ecrion.DAS.Java.jar" SimpleJob.java

Step 3: Run the Program

Running the program is done using the java command.

> java -cp ".;C:\Program Files\Ecrion\Data Aggregation Server 2011\Client\Java\Ecrion.DAS.Java.jar" SimpleJob

The last command should have no output. If you have the proper write permissions on your C:\ drive, a file named jobOut.xml should appear at that location.

This concludes our "Simple Job" example. More examples can be found in your Samples folder. Read on below if you want a step by step explanation of the code.

Understanding the Code

First is creating our Engine object:

// create a new engine

Engine eng = new Engine();

Next, we'll need to create a Diagram. In our example, we will use a LocalDiagram constructed from a hard-coded string.

//Make sure that this path is valid!!!

String jobPath = "C:\\Users\\Public\\Documents\\Ecrion\\Data Aggregation Server 2011\\Samples\\Job Samples\\SampleCSV.dax";

rp.Diagram = new LocalDiagram(jobPath);

Set some job parameters. Job Parameters are used to overwrite some key resources in your job, like connection-strings, Web service URLs, etc. The

purpose is to use the same job with various data sources, or to hide some critical aspects of your jobs (like username and password from XML job).

In this sample we will overwrite the CSV file path from job <das:csv-url> element with the id 11.

Now we'll create an output stream (we'll use a FileOutputStream in this example) and call the Aggregate() method on our Engine object.