io.micronaut.cli.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

Author:

Juergen Hoeller

See Also:

getURL(), getURI(), getFile()

Method Summary

Modifier and Type	Method and Description
long	contentLength() Determine the content length for this resource.
Resource	createRelative(String relativePath) Creates a new resource relative to this one.
boolean	exists() Return whether this resource actually exists in physical form.
String	getDescription() Return a description for this resource, to be used for error output when working with the resource.
File	getFile()
String	getFilename() Determine a filename for this resource, i.e.
InputStream	getInputStream() An input stream.
URI	getURI()
URL	getURL()
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

InputStream getInputStream()
                    throws IOException

An input stream.

Returns:

The input stream

Throws:

IOException - if there is an error

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.

Returns:

Whether the resource exists

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.

Returns:

Where the contents can be read

See Also:

getInputStream()

getURL

URL getURL()
    throws IOException

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

URI getURI()
    throws IOException

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

File getFile()
      throws IOException

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

long contentLength()
            throws IOException

Determine the content length for this resource.

Returns:

The content length

Throws:

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

lastModified

long lastModified()
           throws IOException

Determine the last-modified timestamp for this resource.

Returns:

The last-modified timestamp

Throws:

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

getFilename

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.

Returns:

The filename for this resource

getDescription

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.

Returns:

The description for this resouce

See Also:

Object.toString()

createRelative

Resource createRelative(String relativePath)

Creates a new resource relative to this one.

Parameters:

relativePath - The relative path

Returns:

The new resource