com.mitchellbosecke.pebble.loader

Class DelegatingLoader

java.lang.Object

com.mitchellbosecke.pebble.loader.DelegatingLoader

All Implemented Interfaces:

Loader<DelegatingLoaderCacheKey>

public class DelegatingLoader
extends Object
implements Loader<DelegatingLoaderCacheKey>

This loader will delegate control to a list of children loaders. This is the default implementation used by Pebble; it delegates to a classpath loader and a file loader to increase the chances of finding templates with varying setups.

Author:

mbosecke

Constructor Summary

Constructors

Constructor and Description
DelegatingLoader(List<Loader<?>> loaders) Constructor provided with a list of children loaders.

Method Summary

Modifier and Type	Method and Description
DelegatingLoaderCacheKey	createCacheKey(String templateName) This method resolves the given template name to a unique object which can be used as the key within the PebbleEngine.getTemplateCache().
String	getCharset()
String	getPrefix()
Reader	getReader(DelegatingLoaderCacheKey cacheKey) The reader which will be used by Pebble to read the contents of the template.
String	getSuffix()
String	resolveRelativePath(String relativePath, String anchorPath) Resolves the given relativePath based on the given anchorPath.
boolean	resourceExists(String templateName)
void	setCharset(String charset) A method for end users to change the charset used by the loader.
void	setPrefix(String prefix) Optional prefix to help find templates, ex "/WEB-INF/templates/" or "database_schema."
void	setSuffix(String suffix) Optional suffix to help find templates, ex ".html", ".peb"

Methods inherited from class java.lang.Object

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

Constructor Detail

DelegatingLoader

public DelegatingLoader(List<Loader<?>> loaders)

Constructor provided with a list of children loaders.

Parameters:

loaders - A list of loaders to delegate to

Method Detail

getReader

public Reader getReader(DelegatingLoaderCacheKey cacheKey)

Description copied from interface: Loader

The reader which will be used by Pebble to read the contents of the template.

Specified by:

getReader in interface Loader<DelegatingLoaderCacheKey>

Parameters:

cacheKey - the cache key to use to load create the reader.

Returns:

A reader object

getSuffix

public String getSuffix()

setSuffix

public void setSuffix(String suffix)

Description copied from interface: Loader

Optional suffix to help find templates, ex ".html", ".peb"

Specified by:

setSuffix in interface Loader<DelegatingLoaderCacheKey>

Parameters:

suffix - Suffix to attach to template names

getPrefix

public String getPrefix()

setPrefix

public void setPrefix(String prefix)

Description copied from interface: Loader

Optional prefix to help find templates, ex "/WEB-INF/templates/" or "database_schema."

Specified by:

setPrefix in interface Loader<DelegatingLoaderCacheKey>

Parameters:

prefix - Prefix to help find templates

getCharset

public String getCharset()

setCharset

public void setCharset(String charset)

Description copied from interface: Loader

A method for end users to change the charset used by the loader.

Specified by:

setCharset in interface Loader<DelegatingLoaderCacheKey>

Parameters:

charset - Character set used by the loader when building a reader object

resolveRelativePath

public String resolveRelativePath(String relativePath,
                                  String anchorPath)

Description copied from interface: Loader

Resolves the given relativePath based on the given anchorPath.

A path is considered as relative when it starts either with '..' or '.' and followed either by a '/' or '\\' otherwise the assumption is that the provided path is an absolute path.

Specified by:

resolveRelativePath in interface Loader<DelegatingLoaderCacheKey>

Parameters:

relativePath - the relative path which should be resolved.

anchorPath - the anchor path based on which the relative path should be resolved on.

Returns:

the resolved path or null when the path could not be resolved.

createCacheKey

public DelegatingLoaderCacheKey createCacheKey(String templateName)

Description copied from interface: Loader

This method resolves the given template name to a unique object which can be used as the key within the PebbleEngine.getTemplateCache(). The returned object will be passed with Loader.getReader(Object).

The resolve method can eventually add information to the cache key from the context (e.g. user session information, servlet request etc.).

As a concrete example if the loader loads a template created by a user form the database the template name itself is not uniquely identify the template. The identification of the template requires also the user which created the template. Hence for the key the user id and the template name should be used. So the cache key is enhanced by some contextual information.

The implementor of the method can add as many additional contextual information to the returned object. However the following things needs to be considered:

• This method will be called on each PebbleEngine.getTemplate(String). Hence the implementation needs to be fast and eventually use some caching for the lookup process.
• The returned object is used within a cache and hence needs to implement Object.equals(Object) and Object.hashCode().
• The object is kept in memory and hence it should not be to memory heavy.

Depending on this implementation the PebbleEngine.getTemplateCache() should be tuned in a way it can operate optimal. E.g. when the number of potential templates is infinite the cache should evict some templates at some point in time otherwise the stability of the memory is not given anymore.

Specified by:

createCacheKey in interface Loader<DelegatingLoaderCacheKey>

Parameters:

templateName - The name of the template

Returns:

Returns the cache key

resourceExists

public boolean resourceExists(String templateName)

Specified by:

resourceExists in interface Loader<DelegatingLoaderCacheKey>