Developer

10 Perl modules all Java developers should know

There are numerous CPAN modules which are designed to import Java classes into Perl scripts or access Java APIs like Swing, JDBC and JNI. This document lists the ten most important and useful modules in this collection.

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Just like Perl, Java has been around for a while. However, Perl is a scripting language and Java is a true object-oriented language...which perhaps explains why Java and Perl programmers don't usually hang out at the same bars. This is a little bit of a shame, because Java and Perl actually inter-operate fairly well — there are numerous CPAN modules which are designed to import Java classes into Perl scripts or access Java APIs like Swing, JDBC and JNI.

This document lists the ten most important and useful modules (Table A) in this collection — take a look, and you might find something useful for the next time you sit down to write a hybrid Java/Perl application.

Note: You can install CPAN modules directly from the Internet, by following the instructions provided.

Table A


Package Name

Description

Java

This module provides a framework to start a local, or connect to a remote, Java Virtual Machine (JVM). It includes support for VM localization, object creation, method invocation, event listeners and loops, and exceptions.

Use this module when you need to connect to a local or remote JVM through Perl.

Inline::Java

This module is one of the most useful for Java developers switching over to Perl, because it allows them to embed Java code as-is into a Perl script. This code is then automatically compiled and invoked as needed by the Perl interpreter. The module includes support for environment variables, type casting, shared JVMs, arrays, objects and exceptions.

Use this module when you need to embed Java code directly in a Perl script.

Java::Import

This module makes it easy to import and access Java classes from Perl. It includes the ability to call static methods, pass arguments and process return values, work with Java-based data structures, and handle exceptions.

Use this module when you need to access a Java class from a Perl script.

Java::Build

This module provides an alternative to Ant, the traditional Java build tool. It combines Perl's scripting abilities with the standard Java build/package toolset.

Use this module when you require greater control over the build/package process for a Java class.

Java::Swing

The Swing toolkit provides sophisticated GUI controls (toolbars, buttons, and selectors) for Java applications. This module provides an object-based interface to core Swing API calls, and includes support for extended components, listeners and other wrappers.

Use this module when you need to access Java Swing functions through Perl.

JDBC

This module provides an interface to various database systems using JDBC. It includes support for database connections, query execution and result set retrieval, prepared statements and error handling.

Use this module when you need to connect to an RDBMS through a JDBC "pipe", perhaps to make use of a custom JDBC driver class.

Java::SJ

This module provides a framework to customize Java VM configuration, making it possible to run multiple VMs, each with a different startup configuration and service profile. Configurations are expressed in XML.

Use this module when you need to run multiple Java VMs simultaneously on the same system.

Java::JVM::Classfile

This module reads and parses JVM classfiles and expresses the information within them as a series of objects. Various methods are available to retrieve specific information about class methods, properties and visibility.

Use this module to retrieve detailed information about the objects and classes defined in a JVM classfile.

Template::Plugin::Java

This module provides a framework for describing Java classes in XML and then transforming these XML descriptions into Java source code. The XML description may include descriptions of variables and methods, and includes support for type casting and arrays. Two operation modes are supported: command-line, and embedded within a template.

Use this module when you need to create class templates in a standard, easily-parseable format, perhaps for use on different platforms.

Java::JCR::Jackrabbit

This module makes it possible to connect to, and manipulate, a Jackrabbit (JCR) content repository through Perl. It includes support for custom nodes.

Use this module when you need to access a Jackrabbit content repository.

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