plistreader

Class ReaderXMLHandler

java.lang.Object

org.xml.sax.helpers.DefaultHandler

plistreader.ReaderXMLHandler

All Implemented Interfaces:

ContentHandler, DTDHandler, EntityResolver, ErrorHandler

public class ReaderXMLHandler
extends DefaultHandler
implements EntityResolver

Title: PlistReader ReaderXMLHandler

Description: Package to read and write PLIST files on OsX

Copyright: 2007, Gie Spaepen

Company: University of Antwerp

THis class is used by the SAX Parser to, event based, handle the content of the XML file and the DTD file. This class needs a PlistProperties object as input parameter to construct a data tree.

Versions

• Version 1.0: parsed almost everything except arrays or dictionaries that were nested into arrays.
• Version 1.1: enhanced error codes to facilitate debugging of PLIST files.
• Version 1.2: update to parse every nested object possible
• Version 1.3: Dateformat corrected for date tags and real tags can now also be understood by the handler and will be stored as a Double.

Version:

1.3

Author:

Gie Spaepen

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	isDataLoaded Flag to determine if a data tag just passed by
private boolean	isDateLoaded Flag to determine if a date tag just passed by
private boolean	isIntegerLoaded Flag to determine if an integer tag just passed by
private boolean	isKeyLoaded Flag to determine if a key tag just passed by
private boolean	isRealLoaded Flag to determine if a real tag just passed by
private boolean	isStringLoaded Flag to determine if a string tag just passed by
private PlistProperties	rootObject Main PlistProperties object that acts as a root object
private Vector	storageObjects Vector to hold the different data nodes
private String	tempKey String to temporally hold a key

Constructor Summary

Constructors

Constructor and Description
ReaderXMLHandler(PlistProperties _properties) This constructor needs a valid PlistProperties object.

Method Summary

Modifier and Type	Method and Description
void	characters(char[] _chars, int _start, int _len) This function extends the characters function of the DefaultHandler class.
private Date	convertStringToDate(String value) Little helper function to convert a string value to a date object.
void	endElement(String _URI, String _local, String _raw) This function extends the endElement function of the DefaultHandler class.
private void	levelDown(boolean _array) When a closing array or dict tag is encountered this function is called to close the current object, say to fold the last node, and add them to the parent node.
private void	levelUp(boolean _array) When a a dict or array tag is encountered we have to create a new level or node.
InputSource	resolveEntity(String _pubId, String _sysId) Function to implement the org.xml.sax.EntityResolver class.
private void	setProperty(String _key, Object _value) This function handles a key-value pair by adding them to the current and active object: in other words the last open node in a manner of speaking.
void	startElement(String _URI, String _local, String _raw, Attributes atts) This function extends the startElement function of the DefaultHandler class.

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

endDocument, endPrefixMapping, error, fatalError, ignorableWhitespace, notationDecl, processingInstruction, 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

isKeyLoaded

private boolean isKeyLoaded

Flag to determine if a key tag just passed by

isStringLoaded

private boolean isStringLoaded

Flag to determine if a string tag just passed by

isIntegerLoaded

private boolean isIntegerLoaded

Flag to determine if an integer tag just passed by

isRealLoaded

private boolean isRealLoaded

Flag to determine if a real tag just passed by

isDateLoaded

private boolean isDateLoaded

Flag to determine if a date tag just passed by

isDataLoaded

private boolean isDataLoaded

Flag to determine if a data tag just passed by

rootObject

private PlistProperties rootObject

Main PlistProperties object that acts as a root object

tempKey

private String tempKey

String to temporally hold a key

storageObjects

private Vector storageObjects

Vector to hold the different data nodes

Constructor Detail

ReaderXMLHandler

public ReaderXMLHandler(PlistProperties _properties)

This constructor needs a valid PlistProperties object. Don't use the the following code as constructor:
ReaderXMLHandler reader = new ReaderXMLHandler(new PlistProperties());
If you do so, there is no way to retrieve the data since the internal data storage is private

Parameters:

_properties - PlistProperties - The object you want to use afterwards.

Method Detail

startElement

public void startElement(String _URI,
                         String _local,
                         String _raw,
                         Attributes atts)

This function extends the startElement function of the DefaultHandler class. It handles basically the tagnames of opening tags.
When a key, string, date, data or a integer tag passes by it sets the resp. flag to true in order that the characters function knows what to do with the content. A boolean is immediately stored since it is an empty tag. The dict or the array are handled by creating a new level (say node) in the internal data storage object.

Specified by:

startElement in interface ContentHandler

Overrides:

startElement in class DefaultHandler

Parameters:

_URI - String - The namespace URI

_local - String - The tagname without prefixes (the one we need since all the Plist tags are 'simple' tags.

_raw - String - The tagname with prefixes

atts - Attributes - The attributes attached to the element

characters

public void characters(char[] _chars,
                       int _start,
                       int _len)

This function extends the characters function of the DefaultHandler class. It handles basically the tagnames of opening tags.
This function handles the content of a tag. Since booleans, dictionaries and arrays are already handled by the startElement function we only need to handle key, string, integer, data and data tags. A key tag is temporally stored in a string and later on reused to match it's value. The rest is passed to the setProperty function and converted to the resp. object.

Specified by:

characters in interface ContentHandler

Overrides:

characters in class DefaultHandler

Parameters:

_chars - char[]

_start - int

_len - int

convertStringToDate

private Date convertStringToDate(String value)

Little helper function to convert a string value to a date object. Generates an error if the date is malformed.

Parameters:

value - String

Returns:

Date

endElement

public void endElement(String _URI,
                       String _local,
                       String _raw)

This function extends the endElement function of the DefaultHandler class. It handles basically the tagnames of opening tags.
This function is in fact the inverse function of the startElement function by 1) setting all the flags to false for a key, string, integer, date or data tag and moving a level down (say node) when encountering a dictionary or an array.

Specified by:

endElement in interface ContentHandler

Overrides:

endElement in class DefaultHandler

Parameters:

_URI - String - The namespace URI

_local - String - The tagname without prefix

_raw - String - The tagname with prefix

See Also:

startElement(java.lang.String, java.lang.String, java.lang.String, org.xml.sax.Attributes)

resolveEntity

public InputSource resolveEntity(String _pubId,
                                 String _sysId)

Function to implement the org.xml.sax.EntityResolver class. Since the PLIST files generally have a DOCTYPE tag with an URL in it the (stupid) SAX Parser want's to make an internet connection and generates a fatal error if it can't. But, the correct DTD file is located also in the JAR file of this library, so if we meet this tag redirect the parser to the internal DTD file.

Specified by:

resolveEntity in interface EntityResolver

Overrides:

resolveEntity in class DefaultHandler

Parameters:

_pubId - String

_sysId - String

Returns:

InputSource

setProperty

private void setProperty(String _key,
                         Object _value)

This function handles a key-value pair by adding them to the current and active object: in other words the last open node in a manner of speaking. This can be an array, so only the value is added to a temporal Vector holding the array values, or to a PlistProperties object.

Parameters:

_key - String

_value - Object

levelUp

private void levelUp(boolean _array)

When a a dict or array tag is encountered we have to create a new level or node. When it is an array a Vector is added to the data storage and when it is a dict a PlistProperties is added and all the data content is added to those objects. Last: use the parameter to the data storage. The added object will then act as current object to say whether it is an array or not...

Parameters:

_array - boolean - new level is an array level (true) or a dict level (false)

levelDown

private void levelDown(boolean _array)

When a closing array or dict tag is encountered this function is called to close the current object, say to fold the last node, and add them to the parent node. Determine if you're closing an array or not.

Parameters:

_array - boolean - True for arrays and false for dictionaries.