uk.ac.starlink.util

Class SourceReader

java.lang.Object

uk.ac.starlink.util.SourceReader

public class SourceReader
extends java.lang.Object

Convenience class to manipulate XML Sources. Methods are provided to do the useful things you might want done with from a Source. Depending on the type of the input source this may involve an XML transformation or it may not; such a transformation is not performed if it is not required.

The transformer object used in the case that transformations are required may be accessed or set to permit some customisation of the way the transformation is done. Some convenience methods are provided for doing these settings as well.

Constructor Summary

Constructors

Constructor and Description
SourceReader()

Method Summary

Modifier and Type	Method and Description
org.w3c.dom.Node	getDOM(javax.xml.transform.Source src) Returns a DOM Node representing the given source.
org.w3c.dom.Element	getElement(javax.xml.transform.Source src) Returns a DOM Element representing the given source.
javax.xml.transform.Transformer	getTransformer() Returns a reference to the Transformer object used for transformations used by this object.
java.io.InputStream	getXMLStream(javax.xml.transform.Source src) Returns an input stream from which the serialised XML text corresponding to a given Source can be read.
SourceReader	setIncludeDeclaration(boolean flag) Sets whether the writeSource methods will output an XML declaration at the start of the XML output.
SourceReader	setIndent(int indent) Tries to set the indent level used by the writeSource methods.
void	setTransformer(javax.xml.transform.Transformer trans) Sets the transformer object used for transformations.
void	writeSource(javax.xml.transform.Source src, java.io.OutputStream ostrm) Writes the contents of a given Source into a given OutputStream.
void	writeSource(javax.xml.transform.Source src, java.io.Writer wr) Writes the contents of a given Source into a given Writer.

Methods inherited from class java.lang.Object

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

Constructor Detail

SourceReader

public SourceReader()

Method Detail

getTransformer

public javax.xml.transform.Transformer getTransformer()

Returns a reference to the Transformer object used for transformations used by this object. Its characteristics may be changed if required. Note that in the case a transformation is not required (e.g. in the case of getting a DOM node from a source which is already a DOMSource) this transformer will not be used.

Returns:

the transformer object used when transformation is necessary

setTransformer

public void setTransformer(javax.xml.transform.Transformer trans)

Sets the transformer object used for transformations. Note that in the case a transformation is not required (e.g. in the case of getting a DOM node from a source which is already a DOMSource) this transformer will not be used.

Parameters:

trans - the transformer object to be used when transformation is necessary. If null is supplied, a default transformer will be used.

getDOM

public org.w3c.dom.Node getDOM(javax.xml.transform.Source src)
                        throws javax.xml.transform.TransformerException

Returns a DOM Node representing the given source. Transformation errors are handled by this object's Transformer, whose behaviour is in turn determined by its ErrorListener. By default, this SourceReader is installed as the ErrorListener.

Parameters:

src - the Source for which the DOM is required

Returns:

a DOM node (typically an Element) representing the XML data in src

Throws:

javax.xml.transform.TransformerException - if some error occurs in transformation or I/O

getElement

public org.w3c.dom.Element getElement(javax.xml.transform.Source src)
                               throws javax.xml.transform.TransformerException

Returns a DOM Element representing the given source. This convenience method invokes getDOM(javax.xml.transform.Source) and then finds an element in the result - if the result is an element that is returned, but if it is a Document then the top-level document element is returned. Anything else throws an IllegalArgumentException.

Parameters:

src - the Source for which the DOM is required

Returns:

an Element representing the XML data in src

Throws:

javax.xml.transform.TransformerException - if some error occurs in transformation or I/O

java.lang.IllegalArgumentException - if src does not represent a Document or Element

writeSource

public void writeSource(javax.xml.transform.Source src,
                        java.io.Writer wr)
                 throws javax.xml.transform.TransformerException

Writes the contents of a given Source into a given Writer. Additional buffering will be performed on the writer if necessary. The writer will be flushed, but not closed.

Hmm, not sure if the encoding is handled correctly here for SAXSources...

Parameters:

src - the Source to be written

wr - the destination for the content of src

Throws:

javax.xml.transform.TransformerException - if some error occurs in transformation or I/O

writeSource

public void writeSource(javax.xml.transform.Source src,
                        java.io.OutputStream ostrm)
                 throws javax.xml.transform.TransformerException

Writes the contents of a given Source into a given OutputStream. Additional buffering will be performed on the stream if necessary. The stream will be flushed, but not closed.

Parameters:

src - the Source to be written

ostrm - the destination for the content of src

Throws:

javax.xml.transform.TransformerException - if some error occurs in transformation or I/O

getXMLStream

public java.io.InputStream getXMLStream(javax.xml.transform.Source src)

Returns an input stream from which the serialised XML text corresponding to a given Source can be read.

Parameters:

src - the Source to be read

Returns:

an InputStream which will supply the XML serialisation of src

setIndent

public SourceReader setIndent(int indent)

Tries to set the indent level used by the writeSource methods. This method modifies the output properties of the the current transformer to affect the way it does the transformation (so will be undone by a subsequent setTransformer). If the supplied indent value is >=0 then the transformer may add whitespace when producing the XML output; it will be encouraged to prettyprint the XML using indent spaces to indicate element nesting, though whether this is actually done depends on which parser is actually being used by JAXP. If indent<0 then no whitespace will be added when outputting XML.

By default, no whitespace is added.

For convenience the method returns this SourceReader is returned.

Parameters:

indent - indicates if and how whitespace should be added by writeSource methods

Returns:

this SourceReader

setIncludeDeclaration

public SourceReader setIncludeDeclaration(boolean flag)

Sets whether the writeSource methods will output an XML declaration at the start of the XML output. This method modifies the output properties of the the current transformer to affect the way it does the transformation (so will be undone by a subsequent setTransformer).

By default, the declaration is included

For convenience the method returns this SourceReader is returned.

Parameters:

flag - true if the writeSource methods are to output an XML declaration, false if they are not to

Returns:

this SourceReader