gate.creole

Class ResourceReference

java.lang.Object

gate.creole.ResourceReference

All Implemented Interfaces:

Serializable

public class ResourceReference
extends Object
implements Serializable

This class provides a common way of referencing a resource regardless of where it is located. Specifically it allows resources stored within plugins to be referenced without needing to know where the resource is actually located as that information is determined when the resource is accessed. Previously most GATE components used URL instances to refer to resources and to aid in converting existing code to use ResourceReference instead the public API follows that of URL where possible.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected static org.slf4j.Logger	log

Constructor Summary

Constructors

Constructor and Description
ResourceReference(Plugin plugin, String path) Creates a new instance that references a resource within a given Plugin.
ResourceReference(ResourceReference context, String path) Creates a new instance that references a resource identified by resolving the path against an existing ResourceReference.
ResourceReference(URI uri) Create a new instance that references a resource described by a URI.
ResourceReference(URL url) Create a new instance that references a resource accessible via a known URL.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object obj)
int	hashCode()
URLConnection	openConnection() Returns a URLConnection instance that represents a connection to the resource referred to by this ResourceReference.
InputStream	openStream() Opens a connection to this ResourceReference and returns an InputStream for reading from that connection.
String	toExternalForm()
String	toString()
URI	toURI()
URL	toURL() Creates a URL instance that can be used to access the underlying resource.

Methods inherited from class java.lang.Object

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

Field Detail

log

protected static final org.slf4j.Logger log

Constructor Detail

ResourceReference

public ResourceReference(URL url)
                  throws URISyntaxException

Create a new instance that references a resource accessible via a known URL. While a useful constructor in it's own right this also allows old applications that contain URLs as parameters to PRs that now take a ResourceReference to continue to work as the URL will get passed into this constructor automatically as the application is reloaded.

Parameters:

url - the URL of the resource you wish to reference

Throws:

URISyntaxException - if the URL does not strictly conform to RFC 2396 or if it cannot be converted to an absolute URI

ResourceReference

public ResourceReference(URI uri)
                  throws URISyntaxException

Create a new instance that references a resource described by a URI.

Parameters:

uri - the URI of the resource you wish to reference

Throws:

URISyntaxException - if the URI is not absolute

ResourceReference

public ResourceReference(Plugin plugin,
                         String path)
                  throws URISyntaxException

Creates a new instance that references a resource within a given Plugin.

Parameters:

plugin - a Plugin against which to resolve the path. Can be null, but only if the path can be parsed as an absolute URI

path - the path to the resource which will be resolved against the Plugin

Throws:

URISyntaxException - if the reference cannot be converted to an absolute URI

ResourceReference

public ResourceReference(ResourceReference context,
                         String path)
                  throws URISyntaxException

Creates a new instance that references a resource identified by resolving the path against an existing ResourceReference.

Parameters:

context - a ResourceReference against which to resolve the path. Can be null, but only if the path can be parsed as an absolute URI

path - the path to the resource which will be resolved against the context.

Throws:

URISyntaxException - if the reference cannot be converted to an absolute URI

Method Detail

openStream

public InputStream openStream()
                       throws IOException

Opens a connection to this ResourceReference and returns an InputStream for reading from that connection. This method is a shorthand for:

 toURL().openConnection().getInputStream()
 

Returns:

an input stream for reading from the URL connection.

Throws:

IOException - if an I/O exception occurs.

openConnection

public URLConnection openConnection()
                             throws IOException

Returns a URLConnection instance that represents a connection to the resource referred to by this ResourceReference.

It should be noted that a URLConnection instance does not establish the actual network connection on creation. This will happen only when calling URLConnection.connect().

This method is a shorthand for:

 toURL().openConnection()
 

Returns:

a URLConnection linking to the underlying resource.

Throws:

IOException - if an I/O exception occurs.

toURL

public URL toURL()
          throws IOException

Creates a URL instance that can be used to access the underlying resource. It should be noted that the result is not guaranteed to be valid long term and should never be persisted. If you want persistent access then store the ResourceReference instance instead.

Returns:

a URL that currently gives access to the referenced resource.

Throws:

IOException - if an I/O exception occurs.

toURI

public URI toURI()

toString

public String toString()

Overrides:

toString in class Object

toExternalForm

public String toExternalForm()

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object