JSR
223- Scripting for the Java Platform
Java
introduced the support for scripting languages for java platform from Java- 6.
- JSR 223 - Scripting for the Java Platform helps developers integrate the standard java code with the scripting language by a standard framework and API. With this API we can
- Access
and control Java objects from a scripting environment
- Create
web content with scripting languages
- Embed scripting environments within Java based applications
- Java 6 by default ships Javascript Engine Implementation called Rhino provided by the Mozilla
- New scripting engines that compliance JSR 223 can be plugged in to avail the feature. So now the Python, Ruby scripting advantages can also be availed.
- With this new API, now the power of scripting can be availed from the java.
Example: In the below
piece of code, a javascript function called printName(name) is evaluated from
java and the argument is passed is the java object.
public static void main(String[]
args) {
//
create Script-Engine-Manager object
ScriptEngineManager factory = new ScriptEngineManager();
//
Get Script Engine from factory
ScriptEngine engine = factory.getEngineByName("js");
//
Create binding variable to pass value to script
Bindings bindings =
engine.createBindings();
bindings.put("name", "JAS Technologies");
//
evaluate JavaScript code from String
try {
engine.eval("printName(name);" +
"function printName(name){" +
"print(name+' company');" +
"};",
bindings);
} catch
(ScriptException e) {
e.printStackTrace();
}
}
JSR
199 – java Compiler API
1. One
of the cool features introduced in java 6 is to compile the java source file
dynamically.
2. As
a part of JSR 199-JavaTM
Compiler API, there is a standard java Compiler API which defines the
interfaces for java compiler functions and a standard service provider
framework by which vendor can provide implementation for the interfaces.
3. The
API for compilation is now available part of javax.tool package and
ships with Java 6
4. So
having said above what a developer can do with this is
a.
Dynamically compile java source file
b.
Can compile multiple files
c.
Can compile a java source from a string object
d.
Also several advanced options are also available.
Check the API for complete details.
Below is the small example for compiling the java
source file dynamically
public static void main(String[]
args) {
//File
to be compiled
String fileName = "D:/jas/workspace/com/test/compile/CompileMe.java";
//Get
the java compiler
JavaCompiler javaCompiler = ToolProvider.getSystemJavaCompiler();
//Compile
the java file. Look at the API to find more on options
int returnVal =
javaCompiler.run(null, null, null, fileName);
}
Content from CompileMe.java used in the above example
package com.test.compile;
public class CompileMe {
public static void main(String[]
args) {
System.out.println("The JAS Technologies");
}
}
