Package org.springframework.core.io
Class AbstractResource
- java.lang.Object
- org.springframework.core.io.AbstractResource
- All Implemented Interfaces:
InputStreamSource
,Resource
- Direct Known Subclasses:
AbstractFileResolvingResource
,ByteArrayResource
,DescriptiveResource
,FileSystemResource
,InputStreamResource
,PathResource
,VfsResource
public abstract class AbstractResource extends Object implements Resource
Convenience base class forResource
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, Sam Brannen
Constructor Summary
Constructors Constructor Description AbstractResource()
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description long
contentLength()
This method reads the entire InputStream to determine 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 other)
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 returnsnull
, assuming that this resource type does not have a filename.URI
getURI()
This implementation builds a URI based on the URL returned bygetURL()
.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
isFile()
This implementation always returnsfalse
.boolean
isOpen()
This implementation always returnsfalse
.boolean
isReadable()
This implementation always returnstrue
for a resource thatexists
(revised as of 5.1).long
lastModified()
This implementation checks the timestamp of the underlying File, if available.ReadableByteChannel
readableChannel()
This implementation returnsChannels.newChannel(InputStream)
with the result ofInputStreamSource.getInputStream()
.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.InputStreamSource
getInputStream
Methods inherited from interface org.springframework.core.io.Resource
getDescription
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.
isReadable
public boolean isReadable()
This implementation always returnstrue
for a resource thatexists
(revised as of 5.1).- Specified by:
isReadable
in interfaceResource
- See Also:
InputStreamSource.getInputStream()
,Resource.exists()
isOpen
public boolean isOpen()
This implementation always returnsfalse
.
isFile
public boolean isFile()
This implementation always returnsfalse
.- Specified by:
isFile
in interfaceResource
- See Also:
Resource.getFile()
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 interfaceResource
- 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 bygetURL()
.- Specified by:
getURI
in interfaceResource
- 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 interfaceResource
- Throws:
FileNotFoundException
- if the resource cannot be resolved as absolute file path, i.e. if the resource is not available in a file systemIOException
- in case of general resolution/reading failures- See Also:
InputStreamSource.getInputStream()
readableChannel
public ReadableByteChannel readableChannel() throws IOException
This implementation returnsChannels.newChannel(InputStream)
with the result ofInputStreamSource.getInputStream()
.This is the same as in
Resource
's corresponding default method but mirrored here for efficient JVM-level dispatching in a class hierarchy.- Specified by:
readableChannel
in interfaceResource
- Returns:
- the byte channel for the underlying resource (must not be
null
) - Throws:
FileNotFoundException
- if the underlying resource doesn't existIOException
- if the content channel could not be opened- See Also:
InputStreamSource.getInputStream()
contentLength
public long contentLength() throws IOException
This method reads the entire InputStream to determine the content length.For a custom sub-class 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 interfaceResource
- 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
This implementation checks the timestamp of the underlying File, if available.- Specified by:
lastModified
in interfaceResource
- 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:
FileNotFoundException
- if the resource cannot be resolved as an absolute file path, i.e. is not available in a file systemIOException
- in case of general resolution/reading failures
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 interfaceResource
- 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
@Nullable public String getFilename()
This implementation always returnsnull
, assuming that this resource type does not have a filename.- Specified by:
getFilename
in interfaceResource
equals
public boolean equals(@Nullable Object other)
This implementation compares description strings.- Overrides:
equals
in classObject
- See Also:
Resource.getDescription()
hashCode
public int hashCode()
This implementation returns the description's hash code.- Overrides:
hashCode
in classObject
- See Also:
Resource.getDescription()
toString
public String toString()
This implementation returns the description of this resource.- Overrides:
toString
in classObject
- See Also:
Resource.getDescription()