Interface Loader<T>
- All Known Implementing Classes:
AbstractServletLoader
,ClasspathLoader
,DelegatingLoader
,FileLoader
,MemoryLoader
,Servlet5Loader
,ServletLoader
,StringLoader
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Method Summary
Modifier and TypeMethodDescriptioncreateCacheKey
(String templateName) This method resolves the given template name to a unique object which can be used as the key within thePebbleEngine.getTemplateCache()
.The reader which will be used by Pebble to read the contents of the template.resolveRelativePath
(String relativePath, String anchorPath) Resolves the givenrelativePath
based on the givenanchorPath
.boolean
resourceExists
(String templateName) void
setCharset
(String charset) A method for end users to change the charset used by the loader.void
Optional prefix to help find templates, ex "/WEB-INF/templates/" or "database_schema."void
Optional suffix to help find templates, ex ".html", ".peb"
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Method Details
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getReader
The reader which will be used by Pebble to read the contents of the template.- Parameters:
cacheKey
- the cache key to use to load create the reader.- Returns:
- A reader object
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setCharset
A method for end users to change the charset used by the loader.- Parameters:
charset
- Character set used by the loader when building a reader object
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setPrefix
Optional prefix to help find templates, ex "/WEB-INF/templates/" or "database_schema."- Parameters:
prefix
- Prefix to help find templates
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setSuffix
Optional suffix to help find templates, ex ".html", ".peb"- Parameters:
suffix
- Suffix to attach to template names
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resolveRelativePath
Resolves the givenrelativePath
based on the givenanchorPath
.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.
- 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.
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createCacheKey
This method resolves the given template name to a unique object which can be used as the key within thePebbleEngine.getTemplateCache()
. The returned object will be passed withgetReader(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)
andObject.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.- Parameters:
templateName
- The name of the template- Returns:
- Returns the cache key
- This method will be called on each
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resourceExists
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