prajna.structure.io

Class SemanticXmlReader

java.lang.Object

prajna.structure.io.SemanticXmlReader

All Implemented Interfaces:

FormatReader<OwlThing>

public abstract class SemanticXmlReader
extends java.lang.Object
implements FormatReader<OwlThing>

Class for creating semantic ontology objects from XML files. Because both XML schemas and ontologies can become very complex, and the mapping between the two is not straightforward, this class is abstract, and uses reflection to parse individual XML elements.

Subclasses that extend this class for specific XML schemas should implement methods in the form convert_tagName, where tagName is the element tag name for elements that should be converted to Owl objects. The method takes two arguments; the first is the org.w3c.dom.Element object that contains the XML data, and the second is a java.util.List of OwlThing objects. The method should return the top-level OwlThing created (if any). Any new objects created should also be stored in the list. So for instance, a method that parses elements with a tagName of Foo should be OwlThing convert_Foo(Element elem, List<OwlThing> list). The tagName is case-sensitive and should match the tagName in the XML exactly.

Author:

Edward Swing

Constructor Summary

Constructors

Constructor and Description
SemanticXmlReader() Create a new Semantic XML reader without specifying a file or directory.
SemanticXmlReader(java.io.File file) Create a new Semantic XML reader from a file or directory.
SemanticXmlReader(java.net.URL xmlUrl) Create a new reader from a URL.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	canRead() Return whether the reader can read data
void	close() Close the reader, clearing any references to connections
protected java.lang.String	getBaseTag(org.w3c.dom.Element elem) Get the base tag - the tag without the prefix - for an element.
java.lang.String	getFilters() Get the filters for this reader.
java.lang.String	getSource() Get the source of the data.
boolean	hasMoreData() Return whether the reader has more data
protected void	loadDatatypeProps(OwlThing thing, org.w3c.dom.Element elem) Load data properties when the element tag name matches a datatype property from the ontology.
java.util.List<OwlThing>	readData() Read the XML data, parsing it into a list of OWL objects.
protected OwlThing	readElement(org.w3c.dom.Element elem, java.util.List<OwlThing> list) Read an element, converting it or its child elements to OwlThings.
void	setFilters(java.lang.String filters) Set any filters for processing.
void	setSource(java.lang.String source) Set the source.

Methods inherited from class java.lang.Object

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

Constructor Detail

SemanticXmlReader

public SemanticXmlReader()

Create a new Semantic XML reader without specifying a file or directory. This reader must be initialized using the setSource() method.

SemanticXmlReader

public SemanticXmlReader(java.io.File file)

Create a new Semantic XML reader from a file or directory. If the file argument is a directory, the reader will read all files in the directory, sequentially

Parameters:

file - the file to read

SemanticXmlReader

public SemanticXmlReader(java.net.URL xmlUrl)

Create a new reader from a URL. This constructor opens the URL stream and prepares to read the contents

Parameters:

xmlUrl - the URL to read data from

Method Detail

canRead

public boolean canRead()

Return whether the reader can read data

Specified by:

canRead in interface FormatReader<OwlThing>

Returns:

true if the reader is in a state to read, false otherwise

close

public void close()

Close the reader, clearing any references to connections

Specified by:

close in interface FormatReader<OwlThing>

getBaseTag

protected java.lang.String getBaseTag(org.w3c.dom.Element elem)

Get the base tag - the tag without the prefix - for an element. This method gets the tag, strips any prefix from the tag, and returns the result. So for an element with a tag foo:bar, this method would return bar.

Parameters:

elem -

Returns:

the base tag

getFilters

public java.lang.String getFilters()

Get the filters for this reader. This method should return the string passed into the setFilters() method. The default implementation returns null

Specified by:

getFilters in interface FormatReader<OwlThing>

Returns:

the filters for this reader

getSource

public java.lang.String getSource()

Get the source of the data. This will return the URL or file name

Specified by:

getSource in interface FormatReader<OwlThing>

Returns:

the data source

hasMoreData

public boolean hasMoreData()

Return whether the reader has more data

Specified by:

hasMoreData in interface FormatReader<OwlThing>

Returns:

true if the reader has more data, false otherwise

loadDatatypeProps

protected void loadDatatypeProps(OwlThing thing,
                     org.w3c.dom.Element elem)

Load data properties when the element tag name matches a datatype property from the ontology. The child elements should be simple elements with text values.

Parameters:

thing - the OwlThing to add properties to

elem - the element containing the child elements

readData

public java.util.List<OwlThing> readData()

Read the XML data, parsing it into a list of OWL objects. If the source was a directory, this method will read the contents of the next file in the directory. Otherwise, it will simply read the contents of the file or URL stream.

Specified by:

readData in interface FormatReader<OwlThing>

Returns:

a list of OWL things created from the XML

readElement

protected OwlThing readElement(org.w3c.dom.Element elem,
                   java.util.List<OwlThing> list)

Read an element, converting it or its child elements to OwlThings. This method first determines if a method called convert_tagName exists, where tagName is the tagName of the XML element (removing any prefix delineated by a colon). If the convert_tagName method exists, it is invoked with the element and list. Otherwise, this method reads all child elements, invoking this method recursively.

Any new objects are stored in the list of OwlThings provided.

Parameters:

elem - the element to read

list - the list of elements. The contents of the list are modified by this method

setFilters

public void setFilters(java.lang.String filters)

Set any filters for processing. The default implementation does nothing

Specified by:

setFilters in interface FormatReader<OwlThing>

Parameters:

filters - the set of filters.

setSource

public void setSource(java.lang.String source)

Set the source. If the argument is a URL, this method sets the source to the specified URL. If it is a file path, the source is set to the file path. If it is a directory, the method initializes the directory file list, and prepares to read each file in the directory

Specified by:

setSource in interface FormatReader<OwlThing>

Parameters:

source - the source