org.geotools.xsd

Class Encoder

Object

Encoder

public class Encoder
extends Object

Encodes objects as xml based on a schema.

The function of the encoder is to traverse a tree of objects serializing them out as xml as it goes. Navigation and serialization of the tree is performed by instances of Binding which are bound to types in the schema.

To execute the encoder, one must have 3 bits of information:

1. The root object in the tree to be encoded
2. The schema / configuration of the instance document being encoded.
3. A name of the element defined in the schema which corresponds to the root object in the tree.

As an example, consider the encoding of a Filter instance.

         
  //instantiate the configuration for the filter schema
  Configuration configuration = new OGCConfiguration();

  //create the encoder
  Encoder encoder = new Encoder( configuration );

  //get a filter
  Filter filter = ...;

  //get the name of the 'filter' element in the schema
  QName name = new QName( "http://www.opengis.net/ogc", "Filter" );

  //encode
  encoder.encode( filter, name );
         
 

Author:

Justin Deoliveira, The Open Planning Project

Field Summary

Fields

Modifier and Type	Field and Description
static QName	COMMENT Special name recognized by the encoder as a comment.

Constructor Summary

Constructors

Constructor and Description
Encoder(Configuration configuration) Creates an encoder from a configuration.
Encoder(Configuration configuration, XSDSchema schema) Creates an encoder from a configuration and a specific schema instance.

Method Summary

Modifier and Type	Method and Description
protected void	closeIterator(Iterator iterator, Object source)
protected void	comment(Element element)
void	encode(Object object, QName name, ContentHandler handler)
void	encode(Object object, QName name, OutputStream out) Encodes an object.
protected Node	encode(Object object, XSDNamedComponent component)
protected Node	encode(Object object, XSDNamedComponent component, XSDTypeDefinition container)
Document	encodeAsDOM(Object object, QName name) Encodes an object directly to a dom.
String	encodeAsString(Object object, QName name) Encodes an object directly to a string.
protected void	end(Element element, XSDElementDeclaration declaration)
BindingLoader	getBindingLoader() Returns the object used to load xml bindings in this encoder
BindingWalker	getBindingWalker()
Configuration	getConfiguration() Returns the configuration used by the encoder
PicoContainer	getContext() Returns the Pico context used by this encoder
Document	getDocument()
Charset	getEncoding() Returns the Charset defining the character encoding scheme this Encoder uses to encode XML content.
int	getIndentSize() Returns the indentation specified.
int	getLineWidth() Returns the line width for breaking up long lines.
NamespaceSupport	getNamespaces() Returns the namespace mappings maintained by the encoder.
XSDSchema	getSchema()
static XSDSchema	getSchema(Configuration configuration)
SchemaIndex	getSchemaIndex()
boolean	isIndenting() Returns whether this Encoder produces indented XML.
boolean	isOmitXMLDeclaration() Returns true if the XML document declaration should be omitted.
void	setEncoding(Charset charset) Sets the charset encoding scheme to be used in encoding XML content.
void	setIndenting(boolean doIndent) Sets the indentation on and off.
void	setIndentSize(int indentSize) Sets the indentation level in number of spaces used.
void	setInline(boolean inline) Sets the encoder to "inline" mode.
void	setLineWidth(int lineWidth) Sets the line width.
void	setNamespaceAware(boolean namespaceAware) Sets wether the encoder should be namespace aware.
void	setOmitXMLDeclaration(boolean ommitXmlDeclaration) Sets XML declaration omitting on and off.
void	setRootElementType(QName rootElementType) Informs the encoder of the type of the root element to be used in cases where it can not be inferred.
void	setSchemaLocation(String namespaceURI, String location) Sets the schema location for a particular namespace uri.
protected void	start(Element element, XSDElementDeclaration declaration)

Methods inherited from class Object

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

Field Detail

COMMENT

public static final QName COMMENT

Special name recognized by the encoder as a comment.

Bindings can return this name in ComplexBinding.getProperties(Object, XSDElementDeclaration) to provide comments to be encoded.

Constructor Detail

Encoder

public Encoder(Configuration configuration)

Creates an encoder from a configuration.

This constructor calls through to Encoder(Configuration, XSDSchema) obtaining the schema instance from Configuration#getXSD()#getSchema()).

Parameters:

configuration - The encoder configuration.

Encoder

public Encoder(Configuration configuration,
               XSDSchema schema)

Creates an encoder from a configuration and a specific schema instance.

Parameters:

configuration - The encoder configuration.

schema - The schema instance.

Method Detail

getSchema

public static XSDSchema getSchema(Configuration configuration)

setEncoding

public void setEncoding(Charset charset)

Sets the charset encoding scheme to be used in encoding XML content.

This encoding will determine the resulting character encoding for the XML content generated by this Encoder and will be reflected in the XML declaration tag.

Parameters:

charset - the (non null) charset to encode XML content accordingly to

getEncoding

public Charset getEncoding()

Returns the Charset defining the character encoding scheme this Encoder uses to encode XML content.

If not otherwise set through setEncoding(Charset), UTF-8 is used.

Returns:

the character set used for encoding

setOmitXMLDeclaration

public void setOmitXMLDeclaration(boolean ommitXmlDeclaration)

Sets XML declaration omitting on and off.

Parameters:

ommitXmlDeclaration - true if XML declaration should be omitted

isOmitXMLDeclaration

public boolean isOmitXMLDeclaration()

Returns true if the XML document declaration should be omitted. The default is false.

Returns:

whether the xml declaration is omitted, defaults to false.

setIndenting

public void setIndenting(boolean doIndent)

Sets the indentation on and off.

When set on, the default indentation level and default line wrapping is used (see getIndentSize() and getLineWidth()). To specify a different indentation level or line wrapping, use setIndentSize(int) and setLineWidth(int)).

Parameters:

doIndent - true if indentation should be on

isIndenting

public boolean isIndenting()

Returns whether this Encoder produces indented XML.

Defaults to false.

Returns:

true if indentation was specified

See Also:

setIndentSize(int)

setIndentSize

public void setIndentSize(int indentSize)

Sets the indentation level in number of spaces used.

The document will not be indented if the indentation is set to zero. Calling setIndenting(false) will reset this value to zero, calling it with true will reset this value to the default.

Parameters:

indentSize - the number, greater or equal than zero, of characters used to indent, zero for no indentation.

getIndentSize

public int getIndentSize()

Returns the indentation specified.

If no indentation was specified, zero is returned and the document should not be indented.

Defaults to 4

Returns:

zero if not indenting, the number of white space characters used for indentation otherwise.

See Also:

setIndenting(boolean)

setLineWidth

public void setLineWidth(int lineWidth)

Sets the line width.

If zero then no line wrapping will occur. Calling setIndenting(false) will reset this value to zero, calling setIndenting(true) will set this value to the default.

Parameters:

lineWidth - a number >= 0 used to limit line widths

getLineWidth

public int getLineWidth()

Returns the line width for breaking up long lines.

When indenting, and only when indenting, long lines will be broken at space boundaries based on this line width. No line wrapping occurs if this value is zero.

Defaults to 72 characters per line.

Returns:

the number of characters at which line wrapping happens, or zero for no line wrapping

See Also:

isIndenting()

setNamespaceAware

public void setNamespaceAware(boolean namespaceAware)

Sets wether the encoder should be namespace aware.

Warning that setting this to false will result in no namespace prefixes on encoded elements and attributes, and no schema declarations on the root element.document;

getNamespaces

public NamespaceSupport getNamespaces()

Returns the namespace mappings maintained by the encoder.

Clients may register additional namespace mappings. This is useful when an application wishes to provide some "default" namespace mappings.

Clients should register namespace mappings in the current "context", ie do not call NamespaceSupport.pushContext(). Example: Encoder parser = new Encoder( ... ); encoder.getNamespaces().declarePrefix( "foo", "http://www.foo.com" ); ...

Returns:

The namespace support containing prefix to uri mappings.

Since:

2.5

setInline

public void setInline(boolean inline)

Sets the encoder to "inline" mode.

When this flag is set encode(Object, QName, ContentHandler) should be used to encode.

setRootElementType

public void setRootElementType(QName rootElementType)

Informs the encoder of the type of the root element to be used in cases where it can not be inferred.

This method is used in cases where the element being encoded is not declared as global in the schema.

Parameters:

rootElementType - The type name of the root element.

Since:

8.0

setSchemaLocation

public void setSchemaLocation(String namespaceURI,
                              String location)

Sets the schema location for a particular namespace uri.

Registering a schema location will include it on the "schemaLocation" attribute of the root element of the encoding.

Parameters:

namespaceURI - A namespace uri.

location - A schema location.

getBindingWalker

public BindingWalker getBindingWalker()

Returns:

The walker used to traverse bindings, this method is for internal use only.

getSchemaIndex

public SchemaIndex getSchemaIndex()

Returns:

The index of schema components, this method is for internal use only.

getSchema

public XSDSchema getSchema()

Returns:

the schema.

getDocument

public Document getDocument()

Returns:

The document used as a factory to create dom nodes.

encode

public void encode(Object object,
                   QName name,
                   OutputStream out)
            throws IOException

Encodes an object.

An object is encoded as an object, name pair, where the name is the name of an element declaration in a schema.

Parameters:

object - The object being encoded.

name - The name of the element being encoded in the schema.

out - The output stream.

Throws:

IOException

encode

public void encode(Object object,
                   QName name,
                   ContentHandler handler)
            throws IOException,
                   SAXException

Throws:

IOException

SAXException

encodeAsDOM

public Document encodeAsDOM(Object object,
                            QName name)
                     throws IOException,
                            SAXException,
                            TransformerException

Encodes an object directly to a dom.

Note that this method should be used for testing or convenience since it does not stream and loads the entire encoded result into memory.

Throws:

IOException

SAXException

TransformerException

encodeAsString

public String encodeAsString(Object object,
                             QName name)
                      throws IOException

Encodes an object directly to a string.

Note that this method should be used for testing or convenience since it does not stream and loads the entire encoded result into memory.

Throws:

IOException

Since:

8.0

closeIterator

protected void closeIterator(Iterator iterator,
                             Object source)

encode

protected Node encode(Object object,
                      XSDNamedComponent component)

encode

protected Node encode(Object object,
                      XSDNamedComponent component,
                      XSDTypeDefinition container)

start

protected void start(Element element,
                     XSDElementDeclaration declaration)
              throws SAXException

Throws:

SAXException

comment

protected void comment(Element element)
                throws SAXException,
                       IOException

Throws:

SAXException

IOException

end

protected void end(Element element,
                   XSDElementDeclaration declaration)
            throws SAXException

Throws:

SAXException

getConfiguration

public Configuration getConfiguration()

Returns the configuration used by the encoder

Returns:

the configuration

getBindingLoader

public BindingLoader getBindingLoader()

Returns the object used to load xml bindings in this encoder

getContext

public PicoContainer getContext()

Returns the Pico context used by this encoder