org.codehaus.groovy.grails.io.support

Interface Resource

All Known Implementing Classes:

AbstractFileResolvingResource, ClassPathResource, FileSystemResource, UrlResource

public interface Resource

Interface for a resource descriptor that abstracts from the actual type of underlying resource, such as a file or class path resource.

An InputStream can be opened for every resource if it exists in physical form, but a URL or File handle can just be returned for certain resources. The actual behavior is implementation-specific.

Since:

28.12.2003

See Also:

getURL(), getURI(), getFile()

Method Summary

Modifier and Type	Method and Description
long	contentLength() Determine the content length for this resource.
Resource	createRelative(java.lang.String relativePath) Creates a new resource relative to this one
boolean	exists() Return whether this resource actually exists in physical form.
java.lang.String	getDescription() Return a description for this resource, to be used for error output when working with the resource.
java.io.File	getFile() Return a File handle for this resource.
java.lang.String	getFilename() Determine a filename for this resource, i.e.
java.io.InputStream	getInputStream() An input stream
java.net.URI	getURI() Return a URI handle for this resource.
java.net.URL	getURL() Return a URL handle for this resource.
boolean	isReadable() Return whether the contents of this resource can be read, e.g.
long	lastModified() Determine the last-modified timestamp for this resource.

Method Detail

getInputStream

java.io.InputStream getInputStream()
                            throws java.io.IOException

An input stream

Returns:

The input stream

Throws:

java.io.IOException

exists

boolean exists()

Return whether this resource actually exists in physical form.

This method performs a definitive existence check, whereas the existence of a Resource handle only guarantees a valid descriptor handle.

isReadable

boolean isReadable()

Return whether the contents of this resource can be read, e.g. via getInputStream() or getFile().

Will be true for typical resource descriptors; note that actual content reading may still fail when attempted. However, a value of false is a definitive indication that the resource content cannot be read.

See Also:

getInputStream()

getURL

java.net.URL getURL()
             throws java.io.IOException

Return a URL handle for this resource.

Throws:

java.io.IOException - if the resource cannot be resolved as URL, i.e. if the resource is not available as descriptor

getURI

java.net.URI getURI()
             throws java.io.IOException

Return a URI handle for this resource.

Throws:

java.io.IOException - if the resource cannot be resolved as URI, i.e. if the resource is not available as descriptor

getFile

java.io.File getFile()
              throws java.io.IOException

Return a File handle for this resource.

Throws:

java.io.IOException - if the resource cannot be resolved as absolute file path, i.e. if the resource is not available in a file system

contentLength

long contentLength()
            throws java.io.IOException

Determine the content length for this resource.

Throws:

java.io.IOException - if the resource cannot be resolved (in the file system or as some other known physical resource type)

lastModified

long lastModified()
           throws java.io.IOException

Determine the last-modified timestamp for this resource.

Throws:

java.io.IOException - if the resource cannot be resolved (in the file system or as some other known physical resource type)

getFilename

java.lang.String getFilename()

Determine a filename for this resource, i.e. typically the last part of the path: for example, "myfile.txt".

Returns null if this type of resource does not have a filename.

getDescription

java.lang.String getDescription()

Return a description for this resource, to be used for error output when working with the resource.

Implementations are also encouraged to return this value from their toString method.

See Also:

Object.toString()

createRelative

Resource createRelative(java.lang.String relativePath)

Creates a new resource relative to this one

Parameters:

relativePath - The relative path

Returns:

The new resource