org.apache.tapestry5.internal.util

Class VirtualResource

java.lang.Object

org.apache.tapestry5.internal.util.VirtualResource

All Implemented Interfaces:

Resource

Direct Known Subclasses:

ClientLocalizationMessageResource, MessageCatalogResource, UrlResource

public abstract class VirtualResource
extends Object
implements Resource

Base class for virtual resources: resources that are not simply mapped to stored files, but are assembled, as necessary, on the fly. This is used inside Tapestry to expose the application's localized message catalog as a module. Subclasses should implement the Resource.openStream() method to return a stream of the contents of the virtual resource.

Since:

5.4

See Also:

ModuleManager, ModuleDispatcher

Field Summary

Fields

Modifier and Type	Field and Description
protected static Charset	UTF8

Constructor Summary

Constructors

Constructor and Description
VirtualResource()

Method Summary

Methods

Modifier and Type	Method and Description
boolean	exists() Returns true if the resource exists; if a stream to the content of the file may be opened.
Resource	forFile(String relativePath) Returns a Resource based on a relative path, relative to the folder containing the resource.
Resource	forLocale(Locale locale) Returns a localized version of the resource.
String	getFile() Returns the file portion of the Resource path, everything that follows the final forward slash.
String	getFolder() Returns the portion of the path up to the last forward slash; this is the directory or folder portion of the Resource.
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.
protected InputStream	toInputStream(byte[] content)
protected InputStream	toInputStream(String content)
URL	toURL() Returns the URL for the resource, or null if it does not exist.
Resource	withExtension(String extension) Returns a new Resource with the extension changed (or, if the resource does not have an extension, the extension is added).

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.tapestry5.ioc.Resource

openStream

Field Detail

UTF8

protected static final Charset UTF8

Constructor Detail

VirtualResource

public VirtualResource()

Method Detail

exists

public boolean exists()

Description copied from interface: Resource

Returns true if the resource exists; if a stream to the content of the file may be opened. A resource exists if Resource.toURL() 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 though Resource.toURL() returns null.

Specified by:

exists in interface Resource

Returns:

true if the resource exists, false if it does not

toURL

public URL toURL()

Description copied from interface: Resource

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.

Specified by:

toURL in interface Resource

forLocale

public Resource forLocale(Locale locale)

Description copied from interface: Resource

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.

Specified by:

forLocale in interface Resource

forFile

public Resource forFile(String relativePath)

Description copied from interface: Resource

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.

Specified by:

forFile in interface Resource

withExtension

public Resource withExtension(String extension)

Description copied from interface: Resource

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, Resource.toURL() may return null.

Specified by:

withExtension in interface Resource

Parameters:

extension - to apply to the resource, such as "html" or "properties"

Returns:

the new resource

getFolder

public String getFolder()

Description copied from interface: Resource

Returns the portion of the path up to the last forward slash; this is the directory or folder portion of the Resource.

Specified by:

getFolder in interface Resource

getFile

public String getFile()

Description copied from interface: Resource

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.

Specified by:

getFile in interface Resource

getPath

public String getPath()

Description copied from interface: Resource

Return the path (the combination of folder and file). Starting in 5.4, certain "virtual resources", may return an arbitrary value here.

Specified by:

getPath in interface Resource

toInputStream

protected InputStream toInputStream(String content)
                             throws IOException

Throws:

IOException

toInputStream

protected InputStream toInputStream(byte[] content)
                             throws IOException

Throws:

IOException

isVirtual

public boolean isVirtual()

Description copied from interface: Resource

Returns true if the resource is virtual, meaning this is no underlying file. Many operations are unsupported on virtual resources, including Resource.toURL(), Resource.forLocale(java.util.Locale), Resource.withExtension(String), Resource.getFile(), Resource.getFolder(), Resource.getPath()}; these operations will throw an UnsupportedOperationException.

Specified by:

isVirtual in interface Resource