com.topologi.diffx.xml.dom
Class DOMWriterImpl

java.lang.Object
  com.topologi.diffx.xml.dom.DOMWriterImpl

All Implemented Interfaces:

DOMWriter, XMLWriter

public final class DOMWriterImpl
extends Object
implements DOMWriter

A simple implementation of a DOM writer

Provides methods to generate well-formed XML data easily via DOM.

Version:

11 December 2011

Author:

Christophe Lauret

Constructor Summary

DOMWriterImpl()
Creates a new XML writer for DOM using the default implementation on the system.

DOMWriterImpl(Document document)
Creates a new XML writer for DOM.

Method Summary

void	attribute(String name, int value) Writes an attribute.
void	attribute(String name, String value) Writes an attribute.
void	attribute(String uri, String name, int value) Not supported.
void	attribute(String uri, String name, String value) Not supported.
void	close() Does nothing.
void	closeElement() Close the element automatically.
void	element(String name, String text) Opens element, inserts text node and closes.
void	emptyElement(String name) Writes an empty element.
void	emptyElement(String uri, String element) Not supported.
void	flush() Normalises the current element.
Document	getDocument() Returns the DOM document produced by the XML Writer.
void	openElement(String name) Writes a start element tag correctly indented.
void	openElement(String name, boolean hasChildren) Writes a start element tag correctly indented.
void	openElement(String uri, String name) Not supported.
void	openElement(String uri, String name, boolean hasChildren) Not supported.
void	setIndentChars(String spaces) Sets the string to use for indentation.
void	setPrefixMapping(String uri, String prefix) Not supported.
void	writeCDATA(String data) Writes the CDATA section to the DOM.
void	writeComment(String comment) Writes an XML comment.
void	writePI(String target, String data) Writes an XML processing instruction.
void	writeText(char c) This method is expensive as the character has to be converted to a String for DOM.
void	writeText(char[] text, int off, int len) Write the given text correctly for the encoding of this document.
void	writeText(Object o) Writes the string value of an object.
void	writeText(String text) Writes the given text correctly for the encoding of this document.
void	writeXML(char[] text, int off, int len) Write the given XML data.
void	writeXML(String text) Writes the given XML data.
void	xmlDecl() Does nothing.

Methods inherited from class java.lang.Object

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

Constructor Detail

DOMWriterImpl

public DOMWriterImpl()
              throws ParserConfigurationException

Creates a new XML writer for DOM using the default implementation on the system.

Attempts to create the DOM document using:

  DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance()
  DocumentBuilder builder = factory.newDocumentBuilder();
  Document document = builder.newDocument();
 

Throws:

ParserConfigurationException - If thrown by the document builder factory.

DOMWriterImpl

public DOMWriterImpl(Document document)

Creates a new XML writer for DOM.

Parameters:

document - The DOM provided.

Throws:

NullPointerException - If the handler is null.

Method Detail

xmlDecl

public void xmlDecl()

Does nothing.

Specified by:

xmlDecl in interface XMLWriter

setIndentChars

public void setIndentChars(String spaces)

Sets the string to use for indentation.

The string must be only composed of valid spaces characters.

If the string is null then the indentation is turned off.

Specified by:

setIndentChars in interface XMLWriter

Parameters:

spaces - The indentation string to use.

See Also:

Character.isSpaceChar(char)

writeText

public void writeText(String text)

Writes the given text correctly for the encoding of this document.

Does nothing if the text is null.

Specified by:

writeText in interface XMLWriter

Parameters:

text - The text to write

Throws:

DOMException - If thrown by method invoked on the underlying DOM document

writeText

public void writeText(char[] text,
                      int off,
                      int len)

Write the given text correctly for the encoding of this document.

Specified by:

writeText in interface XMLWriter

Parameters:

text - The text to write.

off - The offset where we should start writing the string.

len - The length of the character subarray to write.

Throws:

DOMException - If thrown by method invoked on the underlying DOM document

writeText

public void writeText(char c)

This method is expensive as the character has to be converted to a String for DOM. Writes the given character correctly for the encoding of this document.

Specified by:

writeText in interface XMLWriter

Parameters:

c - The character to write.

Throws:

DOMException - If thrown by method invoked on the underlying DOM document

writeText

public void writeText(Object o)

Writes the string value of an object.

Does nothing if the object is null.

Parameters:

o - The object that should be written as text.

Throws:

DOMException - If thrown by method invoked on the underlying DOM document

See Also:

Object.toString()

writeCDATA

public void writeCDATA(String data)

Writes the CDATA section to the DOM.

Does nothing if the object is null.

Specified by:

writeCDATA in interface XMLWriter

Parameters:

data - The data to write to the section.

Throws:

DOMException - If thrown by method invoked on the underlying DOM document

writeXML

public void writeXML(String text)

Writes the given XML data.

The text is appended as is, therefore it should be escaped properly for the encoding used by the underlying stream writer.

Does nothing if the text is null.

Specified by:

writeXML in interface XMLWriter

Parameters:

text - The text to write.

Throws:

UnsupportedOperationException - XML cannot be written to the DOM

writeXML

public void writeXML(char[] text,
                     int off,
                     int len)
              throws UnsupportedOperationException

Write the given XML data.

The text is appended as is, therefore it should be escaped properly for the encoding used by the underlying stream writer.

Specified by:

writeXML in interface XMLWriter

Parameters:

text - The text to write.

off - The offset where we should start writing the string.

len - The length of the character subarray to write.

Throws:

UnsupportedOperationException - XML cannot be written to the DOM

writeComment

public void writeComment(String comment)
                  throws DOMException

Writes an XML comment.

An XML comment is:

   <!-- comment -->
 

Comments are not indented.

Does not write anything if the comment if null.

Specified by:

writeComment in interface XMLWriter

Parameters:

comment - The comment to be written

Throws:

DOMException - If thrown by method invoked on the underlying DOM document

writePI

public void writePI(String target,
                    String data)
             throws DOMException

Writes an XML processing instruction.

An XML processing intruction is:

   <?target data?>
 

Specified by:

writePI in interface XMLWriter

Parameters:

target - The PI's target.

data - The PI's data.

Throws:

DOMException - If thrown by method invoked on the underlying DOM document

attribute

public void attribute(String name,
                      String value)
               throws DOMException

Writes an attribute.

Specified by:

attribute in interface XMLWriter

Parameters:

name - The name of the attribute.

value - The value of the attribute.

Throws:

DOMException - If thrown by method invoked on the underlying DOM document

attribute

public void attribute(String name,
                      int value)
               throws DOMException

Writes an attribute.

This method for number does not require escaping.

Specified by:

attribute in interface XMLWriter

Parameters:

name - The name of the attribute.

value - The value of the attribute.

Throws:

DOMException - If thrown by method invoked on the underlying DOM document

openElement

public void openElement(String name)
                 throws DOMException

Writes a start element tag correctly indented.

It is the same as openElement("", name, false)

Specified by:

openElement in interface XMLWriter

Parameters:

name - the name of the element

Throws:

DOMException - If thrown by method invoked on the underlying DOM document

See Also:

openElement(java.lang.String, java.lang.String, boolean)

openElement

public void openElement(String name,
                        boolean hasChildren)
                 throws DOMException

Writes a start element tag correctly indented.

Use the hasChildren parameter to specify whether this element is terminal node or not, note: this affects the indenting. To produce correctly indented XML, you should use the same value for this flag when closing the element.

The name can contain attributes and should be a valid xml name.

Specified by:

openElement in interface XMLWriter

Parameters:

name - The name of the element.

hasChildren - true if this element has children.

Throws:

DOMException - If thrown by method invoked on the underlying DOM document

element

public void element(String name,
                    String text)
             throws DOMException

Opens element, inserts text node and closes.

This method should behave like:

   this.openElement(name, false);
   this.writeText(text);
   this.closeElement();
 

Specified by:

element in interface XMLWriter

Parameters:

name - The name of the element.

text - The text of the element.

Throws:

DOMException - If thrown by method invoked on the underlying DOM document

closeElement

public void closeElement()
                  throws DOMException,
                         IllegalCloseElementException

Close the element automatically.

The element is closed symmetrically to the XMLWriter.openElement(String, String, boolean) method if the XML writer is namespace aware or the XMLWriter.openElement(String, boolean)method.

Specified by:

closeElement in interface XMLWriter

Throws:

DOMException - If thrown by method invoked on the underlying DOM document

IllegalCloseElementException

emptyElement

public void emptyElement(String name)
                  throws DOMException

Writes an empty element.

It is possible for the element to contain attributes, however, since there is no character escaping, great care must be taken not to introduce invalid characters. For example:

    <example test="yes"/>
 

Specified by:

emptyElement in interface XMLWriter

Parameters:

name - the name of the element

Throws:

DOMException - If thrown by method invoked on the underlying DOM document

close

public void close()

Does nothing. Close the writer.

Specified by:

close in interface XMLWriter

flush

public void flush()

Normalises the current element.

Specified by:

flush in interface XMLWriter

getDocument

public Document getDocument()

Returns the DOM document produced by the XML Writer.

Specified by:

getDocument in interface DOMWriter

Returns:

The DOM document produced by the XML Writer.

openElement

public void openElement(String uri,
                        String name)
                 throws UnsupportedOperationException

Not supported.

Parameters:

uri - This parameter is ignored.

name - This parameter is ignored.

Throws:

UnsupportedOperationException - This class does not handle namespaces.

openElement

public void openElement(String uri,
                        String name,
                        boolean hasChildren)
                 throws UnsupportedOperationException

Not supported.

Specified by:

openElement in interface XMLWriter

Parameters:

uri - This parameter is ignored.

name - This parameter is ignored.

hasChildren - This parameter is ignored.

Throws:

UnsupportedOperationException - This class does not handle namespaces.

emptyElement

public void emptyElement(String uri,
                         String element)
                  throws UnsupportedOperationException

Not supported.

Specified by:

emptyElement in interface XMLWriter

Parameters:

uri - This parameter is ignored.

element - This parameter is ignored.

Throws:

UnsupportedOperationException - This class does not handle namespaces.

setPrefixMapping

public void setPrefixMapping(String uri,
                             String prefix)
                      throws UnsupportedOperationException

Not supported.

Specified by:

setPrefixMapping in interface XMLWriter

Parameters:

uri - This parameter is ignored.

prefix - This parameter is ignored.

Throws:

UnsupportedOperationException - This class does not handle namespaces.

attribute

public void attribute(String uri,
                      String name,
                      String value)
               throws UnsupportedOperationException

Not supported.

Specified by:

attribute in interface XMLWriter

Parameters:

uri - This parameter is ignored.

name - The name of the attribute.

value - The value of the attribute.

Throws:

UnsupportedOperationException - This class does not handle namespaces.

attribute

public void attribute(String uri,
                      String name,
                      int value)
               throws UnsupportedOperationException

Not supported.

Specified by:

attribute in interface XMLWriter

Parameters:

uri - This parameter is ignored.

name - The name of the attribute.

value - The value of the attribute.

Throws:

UnsupportedOperationException - This class does not handle namespaces.