net.dpml.lang
Class Part

java.lang.Object
  net.dpml.lang.Part

Direct Known Subclasses:

Composition, Plugin, Resource

public abstract class Part

extends Object

Part datastructure.

Version:

1.0.0

Author:

The Digital Product Meta Library

Field Summary

protected static String	PART_FOOTER Part footer.
protected static String	PART_HEADER Part header.
protected static String	PART_SCHEMA_URN Part schema URN.
protected static ValueEncoder	VALUE_ENCODER A value encoder.
protected static String	XML_HEADER Default XML header.

Constructor Summary

Part(Logger logger, Info info, Classpath classpath)
Creation of a new part datastructure.

Part(Logger logger, Info info, Classpath classpath, String label)
Creation of a new part datastructure.

Method Summary

void	encode(OutputStream output) Externalize the part to XML.
protected abstract void	encodeStrategy(Writer writer, String pad) Encode this part strategy to XML.
boolean	equals(Object other) Test is this part is equiovalent to the supplied part.
ClassLoader	getClassLoader() Get the implementation classloader.
Classpath	getClasspath() Get the part classpath definition.
Object	getContent() Return the default part content.
protected Object	getContent(Class c) Return the part content or null if the result type is unresolvable relative to the supplied classes argument.
Object	getContent(Class[] classes) Return the part content or null if the result type is unresolvable relative to the supplied classes argument.
Info	getInfo() Get the part info descriptor.
protected Logger	getLogger() Get the assigned logging channel.
int	hashCode() Get the part hashcode.
abstract Object	instantiate(Object[] args) Instantiate a value.
static Part	load(URI uri) Load a part from an external XML source with part caching.
static Part	load(URI uri, boolean cache) Load a part from an external XML source.

Methods inherited from class java.lang.Object

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

Field Detail

VALUE_ENCODER

protected static final ValueEncoder VALUE_ENCODER

A value encoder.

XML_HEADER

protected static final String XML_HEADER

Default XML header.

See Also:

Constant Field Values

PART_SCHEMA_URN

protected static final String PART_SCHEMA_URN

Part schema URN.

See Also:

Constant Field Values

PART_HEADER

protected static final String PART_HEADER

Part header.

See Also:

Constant Field Values

PART_FOOTER

protected static final String PART_FOOTER

Part footer.

See Also:

Constant Field Values

Constructor Detail

Part

public Part(Logger logger,
            Info info,
            Classpath classpath)
     throws IOException

Creation of a new part datastructure.

Parameters:

logger - the logging channel

info - the info descriptor

classpath - the part classpath definition

Throws:

IOException - if an I/O error occurs

Part

public Part(Logger logger,
            Info info,
            Classpath classpath,
            String label)
     throws IOException

Creation of a new part datastructure.

Parameters:

logger - the logging channel

info - the info descriptor

classpath - the part classpath definition

label - debug label

Throws:

IOException - if an I/O error occurs

Method Detail

load

public static Part load(URI uri)
                 throws IOException

Load a part from an external XML source with part caching.

Parameters:

uri - the external part source

Returns:

the resolved part

Throws:

IOException - of an I/O error occurs

load

public static Part load(URI uri,
                        boolean cache)
                 throws IOException

Load a part from an external XML source.

Parameters:

uri - the external part source

cache - the cache policy

Returns:

the resolved part

Throws:

IOException - of an I/O error occurs

getContent

public Object getContent()
                  throws IOException

Return the default part content.

Returns:

the result of part instantiation

Throws:

IOException - if an IO error occurs

getContent

public Object getContent(Class[] classes)
                  throws IOException

Return the part content or null if the result type is unresolvable relative to the supplied classes argument.

Parameters:

classes - the content type selection classes

Returns:

the content

Throws:

IOException - if an IO error occurs

getContent

protected Object getContent(Class c)
                     throws IOException

Return the part content or null if the result type is unresolvable relative to the supplied classes argument. Recognized class arguments include Info, Classpath, Part, ClassLoader, and Object.

Parameters:

c - the content type class

Returns:

the content

Throws:

IOException - if an IO error occurs

getInfo

public Info getInfo()

Get the part info descriptor.

Returns:

the part info datastructure

getClasspath

public Classpath getClasspath()

Get the part classpath definition.

Returns:

the classpath definition

instantiate

public abstract Object instantiate(Object[] args)
                            throws Exception

Instantiate a value.

Parameters:

args - supplimentary arguments

Returns:

the resolved instance

Throws:

Exception - if a deployment error occurs

encode

public void encode(OutputStream output)
            throws IOException

Externalize the part to XML.

Parameters:

output - the output stream

Throws:

IOException - if an I/O error occurs

equals

public boolean equals(Object other)

Test is this part is equiovalent to the supplied part.

Parameters:

other - the other object

Returns:

true if the parts are equivalent

hashCode

public int hashCode()

Get the part hashcode.

Returns:

the hash value

encodeStrategy

protected abstract void encodeStrategy(Writer writer,
                                       String pad)
                                throws IOException

Encode this part strategy to XML.

Parameters:

writer - the output stream writer

pad - the character offset

Throws:

IOException - if an I/O error occurs during part externalization

getClassLoader

public ClassLoader getClassLoader()

Get the implementation classloader.

Returns:

the resolved classloader

getLogger

protected Logger getLogger()

Get the assigned logging channel.

Returns:

the logging channel