Spring Framework

org.springframework.core.io
Class AbstractResource

java.lang.Object
  extended by org.springframework.core.io.AbstractResource
All Implemented Interfaces:
InputStreamSource, Resource
Direct Known Subclasses:
AbstractFileResolvingResource, ByteArrayResource, DescriptiveResource, FileSystemResource, InputStreamResource, VfsResource

public abstract class AbstractResource
extends java.lang.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.

Since:
28.12.2003
Author:
Juergen Hoeller

Constructor Summary
AbstractResource()
           
 
Method Summary
 long contentLength()
          This implementation reads the entire InputStream to calculate the content length.
 Resource createRelative(java.lang.String relativePath)
          This implementation throws a FileNotFoundException, assuming that relative resources cannot be created for this resource.
 boolean equals(java.lang.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.
 java.io.File getFile()
          This implementation throws a FileNotFoundException, assuming that the resource cannot be resolved to an absolute file path.
protected  java.io.File getFileForLastModifiedCheck()
          Determine the File to use for timestamp checking.
 java.lang.String getFilename()
          This implementation always returns null, assuming that this resource type does not have a filename.
 java.net.URI getURI()
          This implementation builds a URI based on the URL returned by getURL().
 java.net.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.
 java.lang.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 org.springframework.core.io.Resource
getDescription, 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

isReadable

public boolean isReadable()
This implementation always returns true.

Specified by:
isReadable in interface Resource
See Also:
Resource.getInputStream()

isOpen

public boolean isOpen()
This implementation always returns false.

Specified by:
isOpen in interface Resource

getURL

public java.net.URL getURL()
                    throws java.io.IOException
This implementation throws a FileNotFoundException, assuming that the resource cannot be resolved to a URL.

Specified by:
getURL in interface Resource
Throws:
java.io.IOException - if the resource cannot be resolved as URL, i.e. if the resource is not available as descriptor

getURI

public java.net.URI getURI()
                    throws java.io.IOException
This implementation builds a URI based on the URL returned by getURL().

Specified by:
getURI in interface Resource
Throws:
java.io.IOException - if the resource cannot be resolved as URI, i.e. if the resource is not available as descriptor

getFile

public java.io.File getFile()
                     throws java.io.IOException
This implementation throws a FileNotFoundException, assuming that the resource cannot be resolved to an absolute file path.

Specified by:
getFile in interface 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

public long contentLength()
                   throws java.io.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
Throws:
java.lang.IllegalStateException - if Resource.getInputStream() returns null.
java.io.IOException - if the resource cannot be resolved (in the file system or as some other known physical resource type)
See Also:
Resource.getInputStream()

lastModified

public long lastModified()
                  throws java.io.IOException
This implementation checks the timestamp of the underlying File, if available.

Specified by:
lastModified in interface Resource
Throws:
java.io.IOException - if the resource cannot be resolved (in the file system or as some other known physical resource type)
See Also:
getFileForLastModifiedCheck()

getFileForLastModifiedCheck

protected java.io.File getFileForLastModifiedCheck()
                                            throws java.io.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:
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

createRelative

public Resource createRelative(java.lang.String relativePath)
                        throws java.io.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:
java.io.IOException - if the relative resource cannot be determined

getFilename

public java.lang.String getFilename()
                             throws java.lang.IllegalStateException
This implementation always returns null, assuming that this resource type does not have a filename.

Specified by:
getFilename in interface Resource
Throws:
java.lang.IllegalStateException

toString

public java.lang.String toString()
This implementation returns the description of this resource.

Overrides:
toString in class java.lang.Object
See Also:
Resource.getDescription()

equals

public boolean equals(java.lang.Object obj)
This implementation compares description strings.

Overrides:
equals in class java.lang.Object
See Also:
Resource.getDescription()

hashCode

public int hashCode()
This implementation returns the description's hash code.

Overrides:
hashCode in class java.lang.Object
See Also:
Resource.getDescription()

Spring Framework