Language - Java

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JavaJava is a modern, object-oriented programming language developed by Oracle.

Introduction

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Quick Downloads

Just need the Java documentation, drivers, libraries, and examples? Here they are:

Documentation

Example Code

Libraries and Drivers

Getting started with Java

If you are new to writing code for Phidgets, we recommend starting by running, then modifying existing examples. This will allow you to:

  • Make sure your libraries are properly linked
  • Go from source code to a test application as quickly as possible
  • Ensure your Phidget is hooked up properly

Instructions are divided up by operating system. Choose:

Windows(2000/XP/Vista/7)

Description of Library Files

Java programs on Windows depend on the following files, which the installers above put onto your system:

  • phidget21.dll contains the actual Phidgets library, which is used at run-time. If you used our installer, it's already placed in C:\Windows\System32. It can be manually installed - check our Manual Installation instructions.
  • phidget21.jar is the Phidgets Java library for JDK 1.4.2 or higher. Your compiler has to know where this file is. By default, our installer puts this file into C:\Program Files\Phidgets. So, you can either point your compiler to that location, or copy and link to it in a directory for your project workspace. For more information, please see the section for your specific compiler/environment. If you do not want to use our installer, you can download the file.

Running the examples and writing your own code can be fairly compiler-specific, so we include instructions for each compilers/environments.

Mac OS X

Java has excellent support on Mac OS X through the Java Compiler.

The first step in using Java on Mac is to install the Phidget libraries. Compile and install them as explained on the getting started guide for your device. Then, the OS - Mac OS X page also describes the different Phidget files, their installed locations, and their roles....

Running the examples and writing your own code can be fairly compiler-specific, so we include instructions for each compilers/environments.

Linux

Java has excellent support on Mac OS X through the Java Compiler.

The first step in using Java on Linux is to install the Phidget libraries. Compile and install them as explained on the main Linux page. That Linux page also describes the different Phidget files, their installed locations, and their roles.

Running the examples and writing your own code can be fairly compiler-specific, so we include instructions for each compilers/environments.

Things to cover that are not covered below:

  • Description of files
    • Dependence on libphidget21.so
    • Using jar in a manifest (including compiled C header)
  • Use of sudo without udev rules installed
  • Makefile in examples
    • Use and expansion
    • Other batch compiling of all examples
  • Differences between gcj and openjdk packages
  • Compiling lines (e.g. .:phidget21)
  • Runtime linking of java file resources
  • Mismatch of javac and java versions
    • On command line
    • On Eclipse (weird error given)
  • Some information about IDEs as given below in windows, but also
    • Binding netbeans to gcj (not sure if it is possible in openjdk)
    • Opening simple examples (not copy and paste)

Compilers/Environments

You can program Phidgets with Java in command line with the javac compiler as well as in IDEs such as NetBeans and Eclipse. This instructions in this section was written for a Windows environment, but the steps also holds true for Mac OS X and Linux environments.

Javac

Use Our Examples

Download the example and unpack them into a folder. Here, you can find example programs for all the devices. If you aren't sure what the software example for your device is called, check the software object listed in the Getting Started guide for your device. Please only use the simple examples. The full examples are intended for the NetBeans IDE.

Ensure that the phidget21.jar is in the same directory as the source code.

To compile in Windows command prompt:

javac -classpath .;phidget21.jar example.java

The command to compile in a Mac OS X and Linux terminal are slightly different. Rather than prefixing phidget21.jar with a semi-colon( ; ), a colon( : ) is used.

javac -classpath .:phidget21.jar example.java

This will create Java bytecode in the form of .class files. On Windows, type the following to run the program:

java -classpath .;phidget21.jar example

On Mac OS X and Linux, type:

java -classpath .:phidget21.jar example


If you wish, you can compile the project as a .jar so there are fewer files to maintain. The [Java SDK] provides the jar utility which packages all the .class files into a single .jar file. To begin, you will have to provide a Manifest file to indicate the program entry point. With your favourite text editor, create a new file with the following content:

Manifest-Version: 1.0
Class-Path: phidget21.jar
Main-Class: example


Ensure that the file ends in a single new line or a carriage return character. Save the file as example.mf and place it in the same directory as the other .class files. Next, create the .jar with:

jar -cfm example.jar example.mf *.class

Afterwards, you can run the .jar with:

java -jar example.jar

Once you have the Java examples running, we have a teaching section below to help you follow them.

Write Your Own Code

When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your development environment to properly link the Phidget Java libraries. Please see the previous section for instructions.

In your code, you will need to include the Phidget library:

import com.phidgets.*;
import com.phidgets.event.*;

The project now has access to the Phidget21 function calls and you are ready to begin coding.

The same teaching section which describes the examples also has further resources for programming your Phidget.

NetBeans

Use Our Examples

You first download the examples, unpack them into a folder, and then find the source code for your device. The source file will be named the same as the software object for your device. If you aren't sure what the software example for your device is called, check the software object listed in the Getting Started guide for your device. The full examples were written in NetBeans, so the rest of this section will use these examples. To use the simple examples, you will have to import the source code into a new NetBeans project.

Open Project

The only thing left to do is to run the examples! Click on Run → Run Project. The project, by default tries to find the phidget21.jar in ..\..\lib.

Run

Once you have the Java examples running, we have a teaching section below to help you follow them.

Write Your Own Code

When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your development environment to properly link the Phidget Java libraries. To begin:

1. Create a new Java application project with a descriptive name such as PhidgetTest.

New Project

2. Add a reference to the Phidgets Java library. In the projects pane, right click Libraries and add the jar.

Add Jar

3. Find and select phidget21.jar.

Add Jar

4. Then, in your code, you will need to include the Phidget library:

import com.phidgets.*;
import com.phidgets.event.*;


The project now has access to the Phidget21 function calls and you are ready to begin coding.

The same teaching section which describes the examples also has further resources for programming your Phidget.

Eclipse

Use Our Examples

1. Download the examples and unpack them into a folder. Here, you can find example programs for all the devices. If you aren't sure what the software example for your device is called, check the software object listed in the Getting Started guide for your device. Please use the simple examples. The full examples were written in NetBeans, and are not compatible with Eclipse. The rest of this guide will assume that the simple examples are used. The example source code will be copied into your Eclipse project later on. Keep note of the file name of the example as a Java class will be created with the same name.

2. Generate a new Java project with a descriptive name such as PhidgetTest. Click next.

New Project

3. On the next screen, go to the libraries panel and add an external jar.

Add Jar

4. Find and select phidget21.jar.

Add Jar

5. Add a new Java class to the project.

New Class

6. Name this class with the same name as the simple example's name.

New Class

7. Copy and paste the example source code over to the class you created.

Source Code

8. The only thing left to do is to run the examples!

Run


Once you have the Java examples running, we have a teaching section below to help you follow them.

Write Your Own Code

When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your development environment to properly link the Phidget Java libraries. Please see the Use Our Examples section for instructions.

In your code, you will need to include the Phidget library:

import com.phidgets.*;
import com.phidgets.event.*;

The project now has access to the Phidget21 function calls and you are ready to begin coding.

The same teaching section which describes the examples also has further resources for programming your Phidget.

Follow The Examples

By following the instructions for your operating system and compiler above, you probably now have a working example and want to understand it better so you can change it to do what you want. This teaching section has resources for you to learn from the examples and write your own.

Next, comes our API information. These resources outline the Phidgets Java methods:

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Example Flow

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Common Problems and Solutions/Workarounds

Here you can put various frequent problems and our recommended solutions.