Using BEAM functionality in your software

The BEAM Toolbox provides various functions that can be easily used in your software (e.g. a data processing module). Once you have created a BEAM Library following the Eclipse configuration notes in this document you can integrate this user library into your software to use the BEAM Java^TM API.

Setting up a new Eclipse project

The Java Project Wizard will help you creating a new Eclipse Project. You can start the Java Project Wizard by clicking File > New > Project, selecting "Java Project" from the wizard list and pressing the Next button. It takes two steps to create the new project.

Step One:

Enter a name for your new project into the "Project name" field.

Set the "Create new project in workspace" radiobutton.

Set the "Create separate source and output folders" radiobutton.

After clicking the Next button a new dialog window containing four tabs "Source", "Project", "Libraries" and "Order and Export" will appear.

Step Two:

Select the "Libraries" tab.

Click the Add Library... button.

Select "user library" from the list.

Select the "user library" you have created in the chapter Configuring Eclipse.

click the Finish button.

After pressing the Finish button Eclipse creates a new project folder in your workspace. Within this folder you will find files and subdirectories storing your project configuration, a \src directory for the source code of your plug-in and an output directory \bin, where eclipse will store the compiled sources of your plug-in.

Now you are able to create Java^TM classes inside of your new project and use the BEAM API functions.

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Developing a new scientific processor using the BEAM API.

To create a new scientific processor you will at least need two classes. One base class that provides the processing algorithms and another class with a main method to start your processor. The BEAM Java^TM API provides an easy to use processing framework.

Perform the following instructions to create the base class for your processor.

Note: For a well structured Java code you should create a suitable package structure to store your classes. In the following example all classes will be stored in the package org.esa.beam.processor.exampleProc. Use New > Package to create your package structure inside the /scr folder of your project or simple enter the prefered package name into to the package field of the new class wizard.

Select New > Class from the menu.
Enter a name for the new class.
Ensure that the creation of public static void main(String[] args) is disabled.
Click the Browse... Button beside the field labeled with "Superclass:".
Enter "Processor" into the field labeled with "Choose a type". All classes in your Worspace and in the imported libraries containing "Processor" in its name will be listed below.
Select the class org.esa.beam.framework.processor.Processor as Superclass for your new class.
Press the OK button to confirm.
Press Finish to create the new class.

Eclipse will create now the new class MyProcessor extending class org.esa.beam.framework.processor.Processor and add empty method bodies for the methods you will have to implement.

Furthermore you will have to create a new class with a main method, so you are able to start your processor.

Select New > Class from the menu.
Enter a name for the new class.
Ensure that the checkbox for creating a "public static void main(String[] args)" is enabled.
Press the OK button to confirm.

Again the BEAM processing framework provides methods for this reason. Use the ProcessorRunner class for starting your processor.

Hint: The Eclipse Code Assist will assist you on typing source code. You can activate it by pressing Ctrl + Space. E.g.: To enter the class name ProcessorRunner you can simply enter the first letters of the class name (e.g. Processor) and press Ctrl + Space.

A list with all classes starting with Processor will appear. Select the ProcessorRunner class from the list. Beside completing your input, Eclipse will automatically apply the necessary import statement.

The ProcessorRunner provides the method runProcessor() that will start your Processor and pass the command line arguments to it.

To run the new created processor you will have to create a run configuration.

Open the run configurations dialog window by clicking Run > Run....
Select "Java Application" from the configurations tree and click the New button.
Now enter a name for the new run configuration and click the Search... button beside the field labeled with "Main class".
Select the main class you have created for your processor.
Press the OK button to confirm.

Click the Apply button to save your new run configuration. After you have started your new created run configuration from this dialog window the first time by clicking the Run button, it can be launched again quickly via the "Run History".

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