org.springframework.core.io

Class AbstractFileResolvingResource

java.lang.Object

org.springframework.core.io.AbstractResource

org.springframework.core.io.AbstractFileResolvingResource

All Implemented Interfaces:

InputStreamSource, Resource

Direct Known Subclasses:

ClassPathResource, ServletContextResource, UrlResource

public abstract class AbstractFileResolvingResource
extends AbstractResource

Abstract base class for resources which resolve URLs into File references, such as UrlResource or ClassPathResource.

Detects the "file" protocol as well as the JBoss "vfs" protocol in URLs, resolving file system references accordingly.

Since:

3.0

Author:

Juergen Hoeller

Constructor Summary

Constructors

Constructor and Description
AbstractFileResolvingResource()

Method Summary

Modifier and Type	Method and Description
long	contentLength() This method reads the entire InputStream to determine the content length.
protected void	customizeConnection(HttpURLConnection con) Customize the given HttpURLConnection before fetching the resource.
protected void	customizeConnection(URLConnection con) Customize the given URLConnection before fetching the resource.
boolean	exists() This implementation checks whether a File can be opened, falling back to whether an InputStream can be opened.
File	getFile() This implementation returns a File reference for the underlying class path resource, provided that it refers to a file in the file system.
protected File	getFile(URI uri) This implementation returns a File reference for the given URI-identified resource, provided that it refers to a file in the file system.
protected File	getFileForLastModifiedCheck() This implementation determines the underlying File (or jar file, in case of a resource in a jar/zip).
boolean	isFile() This implementation always returns false.
protected boolean	isFile(URI uri) Determine whether the given URI represents a file in a file system.
boolean	isReadable() This implementation always returns true for a resource that exists (revised as of 5.1).
long	lastModified() This implementation checks the timestamp of the underlying File, if available.
ReadableByteChannel	readableChannel() This implementation returns a FileChannel for the given URI-identified resource, provided that it refers to a file in the file system.

Methods inherited from class org.springframework.core.io.AbstractResource

createRelative, equals, getFilename, getURI, getURL, hashCode, isOpen, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.springframework.core.io.Resource

getDescription

Methods inherited from interface org.springframework.core.io.InputStreamSource

getInputStream

Constructor Detail

AbstractFileResolvingResource

public AbstractFileResolvingResource()

Method Detail

exists

public boolean exists()

Description copied from class: AbstractResource

This implementation checks whether a File can be opened, falling back to whether an InputStream can be opened.

This will cover both directories and content resources.

Specified by:

exists in interface Resource

Overrides:

exists in class AbstractResource

isReadable

public boolean isReadable()

Description copied from class: AbstractResource

This implementation always returns true for a resource that exists (revised as of 5.1).

Specified by:

isReadable in interface Resource

Overrides:

isReadable in class AbstractResource

See Also:

InputStreamSource.getInputStream(), Resource.exists()

isFile

public boolean isFile()

Description copied from class: AbstractResource

This implementation always returns false.

Specified by:

isFile in interface Resource

Overrides:

isFile in class AbstractResource

See Also:

Resource.getFile()

getFile

public File getFile()
             throws IOException

This implementation returns a File reference for the underlying class path resource, provided that it refers to a file in the file system.

Specified by:

getFile in interface Resource

Overrides:

getFile in class AbstractResource

Throws:

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

IOException - in case of general resolution/reading failures

See Also:

ResourceUtils.getFile(java.net.URL, String)

getFileForLastModifiedCheck

protected File getFileForLastModifiedCheck()
                                    throws IOException

This implementation determines the underlying File (or jar file, in case of a resource in a jar/zip).

Overrides:

getFileForLastModifiedCheck in class AbstractResource

Returns:

the File to use for timestamp checking (never null)

Throws:

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

IOException - in case of general resolution/reading failures

isFile

protected boolean isFile(URI uri)

Determine whether the given URI represents a file in a file system.

Since:

5.0

See Also:

getFile(URI)

getFile

protected File getFile(URI uri)
                throws IOException

This implementation returns a File reference for the given URI-identified resource, provided that it refers to a file in the file system.

Throws:

IOException

See Also:

ResourceUtils.getFile(java.net.URI, String)

readableChannel

public ReadableByteChannel readableChannel()
                                    throws IOException

This implementation returns a FileChannel for the given URI-identified resource, provided that it refers to a file in the file system.

Specified by:

readableChannel in interface Resource

Overrides:

readableChannel in class AbstractResource

Returns:

the byte channel for the underlying resource (must not be null)

Throws:

FileNotFoundException - if the underlying resource doesn't exist

IOException - if the content channel could not be opened

Since:

5.0

See Also:

getFile()

contentLength

public long contentLength()
                   throws IOException

Description copied from class: AbstractResource

This method reads the entire InputStream to determine the content length.

For a custom subclass of InputStreamResource, we strongly recommend overriding this method with a more optimal implementation, e.g. checking File length, or possibly simply returning -1 if the stream can only be read once.

Specified by:

contentLength in interface Resource

Overrides:

contentLength in class AbstractResource

Throws:

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

See Also:

InputStreamSource.getInputStream()

lastModified

public long lastModified()
                  throws IOException

Description copied from class: AbstractResource

This implementation checks the timestamp of the underlying File, if available.

Specified by:

lastModified in interface Resource

Overrides:

lastModified in class AbstractResource

Throws:

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

See Also:

AbstractResource.getFileForLastModifiedCheck()

customizeConnection

protected void customizeConnection(URLConnection con)
                            throws IOException

Customize the given URLConnection before fetching the resource.

Calls ResourceUtils.useCachesIfNecessary(URLConnection) and delegates to customizeConnection(HttpURLConnection) if possible. Can be overridden in subclasses.

Parameters:

con - the URLConnection to customize

Throws:

IOException - if thrown from URLConnection methods

customizeConnection

protected void customizeConnection(HttpURLConnection con)
                            throws IOException

Customize the given HttpURLConnection before fetching the resource.

Can be overridden in subclasses for configuring request headers and timeouts.

Parameters:

con - the HttpURLConnection to customize

Throws:

IOException - if thrown from HttpURLConnection methods