spark.resource

Class AbstractResource

java.lang.Object

spark.resource.AbstractResource

All Implemented Interfaces:

InputStreamResource, Resource

Direct Known Subclasses:

AbstractFileResolvingResource

public abstract class AbstractResource
extends Object
implements Resource

Convenience base class for Resource implementations, pre-implementing typical behavior.

The "exists" method will check whether a File or InputStream can be opened; "isOpen" will always return false; "getURL" and "getFile" throw an exception; and "toString" will return the description.

Author:

Juergen Hoeller Code copied from Spring source. Modifications made (mostly removal of methods) by Per Wendel.

Constructor Summary

Constructors

Constructor and Description
AbstractResource()

Method Summary

Modifier and Type	Method and Description
long	contentLength() This implementation reads the entire InputStream to calculate the content length.
Resource	createRelative(String relativePath) This implementation throws a FileNotFoundException, assuming that relative resources cannot be created for this resource.
boolean	equals(Object obj) This implementation compares description strings.
boolean	exists() This implementation checks whether a File can be opened, falling back to whether an InputStream can be opened.
File	getFile() This implementation throws a FileNotFoundException, assuming that the resource cannot be resolved to an absolute file path.
protected File	getFileForLastModifiedCheck() Determine the File to use for timestamp checking.
String	getFilename() This implementation always returns null, assuming that this resource type does not have a filename.
URI	getURI() This implementation builds a URI based on the URL returned by getURL().
URL	getURL() This implementation throws a FileNotFoundException, assuming that the resource cannot be resolved to a URL.
int	hashCode() This implementation returns the description's hash code.
boolean	isOpen() This implementation always returns false.
boolean	isReadable() This implementation always returns true.
long	lastModified() This implementation checks the timestamp of the underlying File, if available.
String	toString() This implementation returns the description of this resource.

Methods inherited from class java.lang.Object

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

Methods inherited from interface spark.resource.Resource

getDescription

Methods inherited from interface spark.resource.InputStreamResource

getInputStream

Constructor Detail

AbstractResource

public AbstractResource()

Method Detail

exists

public boolean exists()

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

Returns:

if exists

isReadable

public boolean isReadable()

This implementation always returns true.

Specified by:

isReadable in interface Resource

Returns:

if readable

See Also:

InputStreamResource.getInputStream()

isOpen

public boolean isOpen()

This implementation always returns false.

Specified by:

isOpen in interface Resource

Returns:

if open

getURL

public URL getURL()
           throws IOException

This implementation throws a FileNotFoundException, assuming that the resource cannot be resolved to a URL.

Specified by:

getURL in interface Resource

Returns:

a URL handle for this resource.

Throws:

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

getURI

public URI getURI()
           throws IOException

This implementation builds a URI based on the URL returned by getURL().

Specified by:

getURI in interface Resource

Returns:

a URI handle for this resource.

Throws:

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

getFile

public File getFile()
             throws IOException

This implementation throws a FileNotFoundException, assuming that the resource cannot be resolved to an absolute file path.

Specified by:

getFile in interface Resource

Returns:

a File handle for this resource.

Throws:

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

contentLength

public long contentLength()
                   throws IOException

This implementation reads the entire InputStream to calculate the content length. Subclasses will almost always be able to provide a more optimal version of this, e.g. checking a File length.

Specified by:

contentLength in interface Resource

Returns:

the content length for this resource.

Throws:

IllegalStateException - if InputStreamResource.getInputStream() returns null.

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

See Also:

InputStreamResource.getInputStream()

lastModified

public long lastModified()
                  throws IOException

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

Specified by:

lastModified in interface Resource

Returns:

the last-modified timestamp for this resource.

Throws:

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

See Also:

getFileForLastModifiedCheck()

getFileForLastModifiedCheck

protected File getFileForLastModifiedCheck()
                                    throws IOException

Determine the File to use for timestamp checking.

The default implementation delegates to getFile().

Returns:

the File to use for timestamp checking (never null)

Throws:

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

createRelative

public Resource createRelative(String relativePath)
                        throws IOException

This implementation throws a FileNotFoundException, assuming that relative resources cannot be created for this resource.

Specified by:

createRelative in interface Resource

Parameters:

relativePath - the relative path (relative to this resource)

Returns:

the resource handle for the relative resource

Throws:

IOException - if the relative resource cannot be determined

getFilename

public String getFilename()

This implementation always returns null, assuming that this resource type does not have a filename.

Specified by:

getFilename in interface Resource

Returns:

the file name.

toString

public String toString()

This implementation returns the description of this resource.

Overrides:

toString in class Object

See Also:

Resource.getDescription()

equals

public boolean equals(Object obj)

This implementation compares description strings.

Overrides:

equals in class Object

See Also:

Resource.getDescription()

hashCode

public int hashCode()

This implementation returns the description's hash code.

Overrides:

hashCode in class Object

See Also:

Resource.getDescription()