public abstract class ContentHandler extends Object
ContentHandler
is the superclass
of all classes that read an Object
from a
URLConnection
.
An application does not generally call the
getContent
method in this class directly. Instead, an
application calls the getContent
method in class
URL
or in URLConnection
.
The application's content handler factory (an instance of a class that
implements the interface ContentHandlerFactory
set up by a call to
setContentHandlerFactory
is called with a String
giving the
MIME type of the object being received on the socket. The factory returns an
instance of a subclass of ContentHandler
, and its
getContent
method is called to create the object.
If no content handler could be found, URLConnection will look for a content handler in a user-definable set of places. Users can define a vertical-bar delimited set of class prefixes to search through by defining the "java.content.handler.pkgs" property. The class name must be of the form:
{package-prefix}.{major}.{minor}If no user-defined content handler is found, then the system tries to load a specific content-type handler from one of the built-in handlers, if one exists.where {major}.{minor} is formed by taking the content-type string, replacing all slash characters with a
period
('.'), and all other non-alphanumeric characters with the underscore character '_
'. The alphanumeric characters are specifically the 26 uppercase ASCII letters 'A
' through 'Z
', the 26 lowercase ASCII letters 'a
' through 'z
', and the 10 ASCII digits '0
' through '9
'.e.g. YoyoDyne.experimental.text.plain
If the loading of the content handler class would be performed by a classloader that is outside of the delegation chain of the caller, the JVM will need the RuntimePermission "getClassLoader".
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Constructor Summary
Constructors Constructor Description ContentHandler()
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Method Summary
Modifier and Type Method Description abstract Object
getContent(URLConnection urlc)
Given a URL connect stream positioned at the beginning of the representation of an object, this method reads that stream and creates an object from it.Object
getContent(URLConnection urlc, Class[] classes)
Given a URL connect stream positioned at the beginning of the representation of an object, this method reads that stream and creates an object that matches one of the types specified.
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Constructor Details
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ContentHandler
public ContentHandler()
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Method Details
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getContent
Given a URL connect stream positioned at the beginning of the representation of an object, this method reads that stream and creates an object from it.- Parameters:
urlc
- a URL connection.- Returns:
- the object read by the
ContentHandler
. - Throws:
IOException
- if an I/O error occurs while reading the object.
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getContent
Given a URL connect stream positioned at the beginning of the representation of an object, this method reads that stream and creates an object that matches one of the types specified. The default implementation of this method should callgetContent(URLConnection)
and screen the return type for a match of the suggested types.- Parameters:
urlc
- a URL connection.classes
- an array of types requested- Returns:
- the object read by the
ContentHandler
that is the first match of the suggested types ornull
if none of the requested are supported. - Throws:
IOException
- if an I/O error occurs while reading the object.- Since:
- 1.3
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