net.dpml.transit
Class Transit

java.lang.Object
  net.dpml.transit.Transit

public final class Transit
extends Object

The Transit class manages the establishment of a singleton transit instance. The implementation establishes an internal cache management system, a suite of protocol handlers, and a dynamic content handler service. During initialization Transit will load an XML configuration descibing the available remote hosts. The XML file will be resolved using the following strategy:

• if the system property dpml.transit.profile is defined then
  • if the value contains the ':' character the value will be treated as a URL referencing a remote configuration
  • otherwise the value will be treated as a relative file path that is first evaluated relative to the current working directory and a file exists at that location it will be loaded, otherwise, the path will be evaluated relative to the DPML Preferences root directory
• otherwise, the default configuration path dpml/transit/xmls/standard.xml will be resolved relative to the Preferences root directory
• if no default configuration is found, Transit will assign a standard profile

During initialization Transit will create the following system properties:

• dpml.home home directory
• dpml.data data directory
• dpml.prefs preferences repository root directory
• dpml.share shared system root directory
• dpml.transit.version Transit system version

Version:

2.0.2

Author:

Digital Product Management Laboratory

Field Summary

static File	DATA The Transit personal data directory.
static File	HOME The DPML home directory established via assesment of the the ${dpml.home} system property and the DPML_HOME environment variable.
static File	PREFS The Transit personal preferences directory.
static File	SYSTEM If a system property named "dpml.system" is defined then the value is assigned otherwise the implementation will look for an environment variable DPML_SYSTEM.
static String	VERSION The Transit system version.

Method Summary

void	addMonitor(Monitor monitor) Add a monitor to Transit.
File	getCacheDirectory() Return the current cache directory.
Layout	getCacheLayout() Return the cache layout.
ContentHandler	getContentHandler(String type) Return the content handler fo the supplied content type.
static Transit	getInstance() Returns the singleton instance of the transit system.
LinkManager	getLinkManager() Return the link manager.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

HOME

public static final File HOME

The DPML home directory established via assesment of the the ${dpml.home} system property and the DPML_HOME environment variable.

SYSTEM

public static final File SYSTEM

If a system property named "dpml.system" is defined then the value is assigned otherwise the implementation will look for an environment variable DPML_SYSTEM.

DATA

public static final File DATA

The Transit personal data directory. The location of this diectory is system dependent.

PREFS

public static final File PREFS

The Transit personal preferences directory. The location of this diectory is system dependent.

VERSION

public static final String VERSION

The Transit system version.

See Also:

Constant Field Values

Method Detail

getInstance

public static Transit getInstance()
                           throws TransitError

Returns the singleton instance of the transit system. If Transit has not been initialized the transit configuration will be resolved using the System property dpml.transit.profile.

Returns:

the singleton transit instance

Throws:

TransitError - if an error occurs during establishment

getCacheDirectory

public File getCacheDirectory()

Return the current cache directory.

Returns:

the cache directory.

getLinkManager

public LinkManager getLinkManager()

Return the link manager.

Returns:

the link manager

getCacheLayout

public Layout getCacheLayout()

Return the cache layout.

Returns:

the layout

addMonitor

public void addMonitor(Monitor monitor)

Add a monitor to Transit.

Parameters:

monitor - the monitor to add

getContentHandler

public ContentHandler getContentHandler(String type)

Return the content handler fo the supplied content type.

Parameters:

type - the content handler type

Returns:

the content handler or null if no content handler found