gov.nih.nlm.util
Class ObjectXMLSerializer

java.lang.Object
  org.xml.sax.helpers.DefaultHandler
      gov.nih.nlm.util.ObjectXMLSerializer

All Implemented Interfaces:

ContentHandler, DTDHandler, EntityResolver, ErrorHandler

public class ObjectXMLSerializer
extends DefaultHandler

This class is used to provide an XML serialization scheme for ANY java object. This class is thread-safe. It uses only local variables and some static HashMap. Any multi-threaded application can create one instance of this class and then safely call the toXML and fromXML methods in overlapping threads without worrying that it will cause conflicts.

Author:

MEME Group

Nested Class Summary

static interface	ObjectXMLSerializer.NotPersistentIfTransient Objects should implement this if they are to be ignored by the serializer and are marked as transient members.
static interface	ObjectXMLSerializer.Primitive Anything implementing this method should also have a static newInstance(String) method.

Field Summary

HashMap

objects_seen_read

Constructor Summary

ObjectXMLSerializer()
Instantiates an empty ObjectXMLSerializer.

Method Summary

void	characters(char[] chars, int start, int length) Implementation of DefaultHandler API.
static Character	CharacterValueOf(String data) The Character class does not have a valueOf(String) method, this method takes its place in reconstructing primitive values.
void	clear() Clears the various class fields for the next round.
protected void	clearObject() Clears the object stack.
static Date	DateValueOf(String data) The Date classes do not have a valueOf(String) method, this method takes its place in reconstructing primitive values.
void	endElement(String namespace_uri, String simple_name, String qualified_name) Implementation of DefaultHandler API.
Object	forceNewInstance(Class c) This method is responsible for finding a constructor and forcing it to create an intitial object.
Object	fromXML(Reader reader) Creates an object from the XML representation indicated by the specified Reader.
Object	fromXML(Reader reader, boolean validating) Creates an object from the XML representation indicated by the specified Reader.
Object	fromXML(String file) Creates an object from the XML representation indicated by the specified file name.
Object	fromXML(String file, boolean validating) Creates an object from the XML representation indicated by the specified file name.
protected Object	getObject() Returns the top object on the object Stack.
static void	main(String[] argv) The main method performs a self-QA test
void	startElement(String namespace_uri, String simple_name, String qualified_name, Attributes attrs) Handles opening tags.
static String	StringValueOf(String data) The String classes do not have a valueOf(String) method, this method takes its place in reconstructing primitive values.
String	toXML(Object obj) Converts an object to an XML representation.
String	toXML(Object obj, String indent) Converts an object to an XML representation with the specified level of indenting.

Methods inherited from class org.xml.sax.helpers.DefaultHandler

endDocument, endPrefixMapping, error, fatalError, ignorableWhitespace, notationDecl, processingInstruction, resolveEntity, setDocumentLocator, skippedEntity, startDocument, startPrefixMapping, unparsedEntityDecl, warning

Methods inherited from class java.lang.Object

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

Field Detail

objects_seen_read

public HashMap objects_seen_read

Constructor Detail

ObjectXMLSerializer

public ObjectXMLSerializer()

Instantiates an empty ObjectXMLSerializer.

Method Detail

clear

public void clear()

Clears the various class fields for the next round. This should be called between subsequent serializations or de-serializations.

CharacterValueOf

public static Character CharacterValueOf(String data)

The Character class does not have a valueOf(String) method, this method takes its place in reconstructing primitive values.

Parameters:

data - a String

Returns:

the Character in the first position of the specified String

DateValueOf

public static Date DateValueOf(String data)

The Date classes do not have a valueOf(String) method, this method takes its place in reconstructing primitive values. Here, dates are represented as the string value of the long obtained by calling Date.getTime().

Parameters:

data - a String representation of a date

Returns:

the Date corresponding to that string

StringValueOf

public static String StringValueOf(String data)

The String classes do not have a valueOf(String) method, this method takes its place in reconstructing primitive values.

Parameters:

data - the input String

Returns:

the output String

toXML

public String toXML(Object obj)
             throws Exception

Converts an object to an XML representation.

Parameters:

obj - an object to convert

Returns:

a XML representation of the object

Throws:

Exception - if conversion fails

toXML

public String toXML(Object obj,
                    String indent)
             throws Exception

Converts an object to an XML representation with the specified level of indenting.

Parameters:

obj - an object to convert

indent - a String containing space characters

Returns:

a XML representation of the object

Throws:

Exception - if conversion fails

fromXML

public Object fromXML(String file)
               throws Exception

Creates an object from the XML representation indicated by the specified file name.

Parameters:

file - an XML file name

Returns:

the object represented by the file

Throws:

Exception - if conversion fails

fromXML

public Object fromXML(String file,
                      boolean validating)
               throws Exception

Creates an object from the XML representation indicated by the specified file name.

Parameters:

file - an XML file name

validating - a flag indicating whether or not a validating parser should be used

Returns:

the object represented by the file

Throws:

Exception - if conversion fails

fromXML

public Object fromXML(Reader reader)
               throws Exception

Creates an object from the XML representation indicated by the specified Reader.

Parameters:

reader - a Reader object

Returns:

the object represented by the file

Throws:

Exception - if conversion fails

fromXML

public Object fromXML(Reader reader,
                      boolean validating)
               throws Exception

Creates an object from the XML representation indicated by the specified Reader.

Parameters:

reader - an object Reader

validating - a flag indicating whether or not a validating parser should be used

Returns:

the object represented by the file

Throws:

Exception - if conversion fails

getObject

protected Object getObject()
                    throws SAXException

Returns the top object on the object Stack.

Returns:

the top object on the object Stack

Throws:

SAXException - if nothing is on the stack

clearObject

protected void clearObject()

Clears the object stack.

startElement

public void startElement(String namespace_uri,
                         String simple_name,
                         String qualified_name,
                         Attributes attrs)
                  throws SAXException

Handles opening tags.

Specified by:

startElement in interface ContentHandler

Overrides:

startElement in class DefaultHandler

Parameters:

namespace_uri - The namespace URI

simple_name - the simple name of the element

qualified_name - the fully qualified name of the allement

attrs - The element attributes

Throws:

SAXException - if anything goes wrong

characters

public void characters(char[] chars,
                       int start,
                       int length)

Implementation of DefaultHandler API.

Specified by:

characters in interface ContentHandler

Overrides:

characters in class DefaultHandler

Parameters:

chars - characters from within an XML tag

start - start index

length - number of chars in this segment

endElement

public void endElement(String namespace_uri,
                       String simple_name,
                       String qualified_name)
                throws SAXException

Implementation of DefaultHandler API.

Specified by:

endElement in interface ContentHandler

Overrides:

endElement in class DefaultHandler

Parameters:

namespace_uri - the namespace URI

simple_name - the simple name

qualified_name - the qualified name

Throws:

SAXException - if failed to parse object

forceNewInstance

public Object forceNewInstance(Class c)
                        throws Exception

This method is responsible for finding a constructor and forcing it to create an intitial object. It uses default values for the various constructor parameters. If no constructor could be found, or if calling the constructor raises an exception, then we should just bail.

Parameters:

c - An object Class to convert to XML.

Returns:

An object Object representation of converted document.

Throws:

Exception - if conversion fails.

main

public static void main(String[] argv)

The main method performs a self-QA test

Parameters:

argv - An array of argument.