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p>The scripting API consists of interfaces and classes that define
903N/AJava <
font size=1><
sup>TM</
sup></
font> Scripting Engines and provides
903N/Aa framework for their use in Java applications. This API is intended
903N/Afor use by application programmers who wish to execute programs
903N/Awritten in scripting languages in their Java applications. The
903N/Ascripting language programs are usually provided by the end-users of
903N/A <
li><
p><
b>Script execution</
b>: Scripts
903N/A are streams of characters used as sources for programs executed by
903N/A script engines. Script execution uses
903N/A <
li><
p><
b>Binding</
b>: This facility
903N/A allows Java objects to be exposed to script programs as named
903N/A classes are used for this purpose.
903N/A <
li><
p><
b>Compilation</
b>: This
903N/A functionality allows the intermediate code generated by the
903N/A front-end of a script engine to be stored and executed repeatedly.
903N/A This benefits applications that execute the same script multiple
903N/A times. These applications can gain efficiency since the engines'
903N/A front-ends only need to execute once per script rather than once per
903N/A script execution. Note that this functionality is optional and
903N/A script engines may choose not to implement it. Callers need to check
903N/A interface using an <
I>instanceof</
I> check.
<
li><
p><
b>Invocation</
b>: This
functionality allows the reuse of intermediate code generated by a
script engine's front-end. Whereas Compilation allows entire scripts
represented by intermediate code to be re-executed, Invocation
be re-executed. As in the case with compilation, not all script
engines are required to provide this facility. Caller has to check
<
li><
p><
b>Script engine discovery and Metadata</
b>: Applications
written to the Scripting API might have specific requirements on
script engines. Some may require a specific scripting language
and/
or version while others may require a specific implementation
engine
and/
or version. Script engines are packaged in a specified
way so that engines can be discovered at runtime and queried for
attributes. The Engine discovery mechanism is based on the Service
discovery mechanism described in the <
b>Jar File Specification</
b>.
Script engine implementing classes are packaged in jar files that
include a text resource named
resource must include a line for each
that is packaged in the jar file.
discovered using this mechanism. <
code>ScriptEngineFactory</
code> has
methods to query attributes about script engine.