Package org.apache.tapestry5.commons
Interface Resource
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- All Known Implementing Classes:
AbstractResource
,ClasspathResource
,ClientLocalizationMessageResource
,ContextResource
,MessageCatalogResource
,UrlResource
,VirtualResource
public interface Resource
Represents a resource on the server that may be used for server side processing, or may be exposed to the client side. Generally, this represents an abstraction on top of files on the class path and files stored in the web application context. Resources are often used as map keys; they should be immutable and should implement hashCode() and equals().
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description boolean
exists()
Returns true if the resource exists; if a stream to the content of the file may be opened.Resource
forFile(java.lang.String relativePath)
Returns a Resource based on a relative path, relative to the folder containing the resource.Resource
forLocale(java.util.Locale locale)
Returns a localized version of the resource.java.lang.String
getFile()
Returns the file portion of the Resource path, everything that follows the final forward slash.java.lang.String
getFolder()
Returns the portion of the path up to the last forward slash; this is the directory or folder portion of the Resource.java.lang.String
getPath()
Return the path (the combination of folder and file).boolean
isVirtual()
Returns true if the resource is virtual, meaning this is no underlying file.java.io.InputStream
openStream()
Opens a stream to the content of the resource, or returns null if the resource does not exist.java.net.URL
toURL()
Returns the URL for the resource, or null if it does not exist.Resource
withExtension(java.lang.String extension)
Returns a new Resource with the extension changed (or, if the resource does not have an extension, the extension is added).
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Method Detail
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exists
boolean exists()
Returns true if the resource exists; if a stream to the content of the file may be opened. A resource exists iftoURL()
returns a non-null value. Starting in release 5.3.4, the result of this is cached. Starting in 5.4, some "virtual resources", may return true even thoughtoURL()
returns null.- Returns:
- true if the resource exists, false if it does not
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isVirtual
boolean isVirtual()
Returns true if the resource is virtual, meaning this is no underlying file. Many operations are unsupported on virtual resources, includingtoURL()
,forLocale(java.util.Locale)
,withExtension(String)
,getFile()
,getFolder()
,getPath()
}; these operations will throw anUnsupportedOperationException
.- Since:
- 5.4
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openStream
java.io.InputStream openStream() throws java.io.IOException
Opens a stream to the content of the resource, or returns null if the resource does not exist. The native input stream supplied by the resource is wrapped in aBufferedInputStream
.- Returns:
- an open, buffered stream to the content, if available
- Throws:
java.io.IOException
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toURL
java.net.URL toURL()
Returns the URL for the resource, or null if it does not exist. This value is lazily computed; starting in 5.3.4, subclasses may cache the result. Starting in 5.4, some "virtual resources" may return null.
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forLocale
Resource forLocale(java.util.Locale locale)
Returns a localized version of the resource. May return null if no such resource exists. Starting in release 5.3.4, the result of this method is cached internally.
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forFile
Resource forFile(java.lang.String relativePath)
Returns a Resource based on a relative path, relative to the folder containing the resource. Understands the "." (current folder) and ".." (parent folder) conventions, and treats multiple sequential slashes as a single slash. Virtual resources (resources fabricated at runtime) return themselves.
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withExtension
Resource withExtension(java.lang.String extension)
Returns a new Resource with the extension changed (or, if the resource does not have an extension, the extension is added). The new Resource may not exist (that is,toURL()
may return null.- Parameters:
extension
- to apply to the resource, such as "html" or "properties"- Returns:
- the new resource
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getFolder
java.lang.String getFolder()
Returns the portion of the path up to the last forward slash; this is the directory or folder portion of the Resource.
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getFile
java.lang.String getFile()
Returns the file portion of the Resource path, everything that follows the final forward slash. Starting in 5.4, certain kinds of "virtual resources" may return null here.
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getPath
java.lang.String getPath()
Return the path (the combination of folder and file). Starting in 5.4, certain "virtual resources", may return an arbitrary value here.
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