Package org.apache.velocity.runtime.resource.loader

Class ResourceLoader

java.lang.Object

org.apache.velocity.runtime.resource.loader.ResourceLoader

Direct Known Subclasses:

ClasspathResourceLoader, DataSourceResourceLoader, FileResourceLoader, JarResourceLoader, SpringResourceLoader, StringResourceLoader, URLResourceLoader

public abstract class ResourceLoader
extends Object

This is abstract class the all text resource loaders should extend.

Version:

$Id$

Author:

Jason van Zyl, Geir Magnusson Jr., Claude Brisson

Field Summary

Fields

Modifier and Type	Field	Description
protected String	className	Class name for this loader, for logging/debuggin purposes.
protected boolean	isCachingOn	Does this loader want templates produced with it cached in the Runtime.
protected org.slf4j.Logger	log
protected long	modificationCheckInterval	This property will be passed on to the templates that are created with this loader.
protected RuntimeServices	rsvc

Constructor Summary

Constructors

Constructor	Description
ResourceLoader()

Method Summary

Modifier and Type	Method	Description
protected Reader	buildReader(InputStream rawStream, String encoding)	Builds a Reader given a raw InputStream and an encoding.
void	commonInit(RuntimeServices rs, ExtProperties configuration)	This initialization is used by all resource loaders and must be called to set up common properties shared by all resource loaders
String	getClassName()	Return the class name of this resource Loader
abstract long	getLastModified(Resource resource)	Get the last modified time of the InputStream source that was used to create the template.
long	getModificationCheckInterval()	Get the interval at which the InputStream source should be checked for modifications.
abstract Reader	getResourceReader(String source, String encoding)	Get the Reader that the Runtime will parse to create a template.
abstract void	init(ExtProperties configuration)	Initialize the template loader with a a resources class.
boolean	isCachingOn()	The Runtime uses this to find out whether this template loader wants the Runtime to cache templates created with InputStreams provided by this loader.
abstract boolean	isSourceModified(Resource resource)	Given a template, check to see if the source of InputStream has been modified.
boolean	resourceExists(String resourceName)	Check whether any given resource exists.
void	setCachingOn(boolean value)	Set the caching state.
void	setModificationCheckInterval(long modificationCheckInterval)	Set the interval at which the InputStream source should be checked for modifications.

Methods inherited from class java.lang.Object

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

Field Detail

isCachingOn

protected boolean isCachingOn

Does this loader want templates produced with it cached in the Runtime.

modificationCheckInterval

protected long modificationCheckInterval

This property will be passed on to the templates that are created with this loader.

className

protected String className

Class name for this loader, for logging/debuggin purposes.

rsvc

protected RuntimeServices rsvc

log

protected org.slf4j.Logger log

Constructor Detail

ResourceLoader

public ResourceLoader()

Method Detail

commonInit

public void commonInit(RuntimeServices rs,
                       ExtProperties configuration)

This initialization is used by all resource loaders and must be called to set up common properties shared by all resource loaders

Parameters:

rs -

configuration -

init

public abstract void init(ExtProperties configuration)

Initialize the template loader with a a resources class.

Parameters:

configuration -

getResourceReader

public abstract Reader getResourceReader(String source,
                                         String encoding)
                                  throws ResourceNotFoundException

Get the Reader that the Runtime will parse to create a template.

Parameters:

source -

encoding -

Returns:

The reader for the requested resource.

Throws:

ResourceNotFoundException

Since:

2.0

isSourceModified

public abstract boolean isSourceModified(Resource resource)

Given a template, check to see if the source of InputStream has been modified.

Parameters:

resource -

Returns:

True if the resource has been modified.

getLastModified

public abstract long getLastModified(Resource resource)

Get the last modified time of the InputStream source that was used to create the template. We need the template here because we have to extract the name of the template in order to locate the InputStream source.

Parameters:

resource -

Returns:

Time in millis when the resource has been modified.

getClassName

public String getClassName()

Return the class name of this resource Loader

Returns:

Class name of the resource loader.

setCachingOn

public void setCachingOn(boolean value)

Set the caching state. If true, then this loader would like the Runtime to cache templates that have been created with InputStreams provided by this loader.

Parameters:

value -

isCachingOn

public boolean isCachingOn()

The Runtime uses this to find out whether this template loader wants the Runtime to cache templates created with InputStreams provided by this loader.

Returns:

True if this resource loader caches.

setModificationCheckInterval

public void setModificationCheckInterval(long modificationCheckInterval)

Set the interval at which the InputStream source should be checked for modifications.

Parameters:

modificationCheckInterval -

getModificationCheckInterval

public long getModificationCheckInterval()

Get the interval at which the InputStream source should be checked for modifications.

Returns:

The modification check interval.

resourceExists

public boolean resourceExists(String resourceName)

Check whether any given resource exists. This is not really a very efficient test and it can and should be overridden in the subclasses extending ResourceLoader2.

Parameters:

resourceName - The name of a resource.

Returns:

true if a resource exists and can be accessed.

Since:

1.6

buildReader

protected Reader buildReader(InputStream rawStream,
                             String encoding)
                      throws IOException

Builds a Reader given a raw InputStream and an encoding. Should be use by every subclass that whishes to accept optional BOMs in resources. This method does *not* close the given input stream whenever an exception is thrown.

Parameters:

rawStream - The raw input stream.

encoding - The asked encoding.

Returns:

found reader

Throws:

IOException

UnsupportedEncodingException

Since:

2.0