XMLLoader (e-governments egf 2.1.0-FW-SNAPSHOT API)

java.lang.Object
- org.xml.sax.helpers.DefaultHandler
- - com.exilant.exility.common.XMLLoader

All Implemented Interfaces:

ContentHandler, DTDHandler, EntityResolver, ErrorHandler
```
public class XMLLoader
extends DefaultHandler
```
Author:

raghu.bhandi XMLLoader loads an object from an XML source file. It can load a complete object map from a corresponding XML file 1. XML uses only attributes of an node. e.g. or 2. Values of the type Some text value of tag are not used. If found, they are ignored 3. Hierarchies are possible. e.g. .... For an object to be 'loadable' follow these guidelines. (No interface is defined as these are naming conventions, and not methods) 1. For each possible atribute, define a field (data member) of appropriate data type. primitive data types, and string are the only ones to be used. 2. Alternately, you can define a HashMap named 'attributes'. All attributes, for which there is no corresponding field name, are stored in this hashmap as name/value pairs. 3. If the class/object can have children (child nodes) you should plan to load them as well 4. Note that each node in the XML is loaded into one object by default. Each node will have a corresponding class 5. If a child node occurs only once, you can define a field for that with the name matching the tag name. Loader will load the child node into this object. If you just declare it without instantiatiing it, Loader tries teh defalt constructor to iinstantiate it 6. If a type of child node occurs more than once, you can either plan to store them in an array or a HashMap If you need to locate them using key, then HashMap is the preferred way, while array is effecient. You can also store them in ArrayList if you have to add child nodes later (after loader loads them) Loader looks for a field with the name =tagname + 's' . For e.g.

in this case, loader looks for a field with name childs and tries to load all child nodes into this field 7. If array is defined, Loader can determine the calss (Type) of child obbjects. However, if it is HashMap or ArrayList, Loader can not figure out the calss (type) to be used to instantiate teh child object. You have to declare a field with the name of the tag for this. For example, for the above xml, define ChildClass child; HashMap children; 8. The key for HashMap: attribute with name id, key, and name are searched, in that order and used as key for HashMap. 9. If your needs to store child objects are more complex than this, then you can write your own method. a method newChild(String tag, String key) is called by the loader whenever a child node is encountered you can instantiate a child object, store it appropriately, and return the reference for the loader to load it. Loader calls endChild(String tag) when the end tag is encountered. This method is optional and you need not provide this. It is called only if it is defined. 10. Tag name of the node is stored in a String field with name as 'node' if such a field is defined for the object (note: if you also have an attribute with name as 'type', the attribute value over-rides the tag name) 11. If any field is of type boolean, then you should specify "true", "yes" or "1" as the value for true. else it is considered to be false;

Constructor Summary

Constructors
Constructor and Description

XMLLoader()

Constructors
Constructor and Description
`XMLLoader()`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`endElement(String namespaceURI, String localName, String qName)` endElement() is called by the parser when the /> or is encountered
`void`	`load(String fileName, Object root)`
`void`	`startElement(String namespaceURI, String localName, String qName, Attributes atts)` Call back methods used by SaxLoader.

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

Constructor Detail
- XMLLoader
```
public XMLLoader()
```

Method Detail

load

public void load(String fileName,
                 Object root)

startElement

public void startElement(String namespaceURI,
                         String localName,
                         String qName,
                         Attributes atts)
                  throws SAXException

Call back methods used by SaxLoader. startElement() and endElement()

Specified by:: startElement in interface ContentHandler
Overrides:: startElement in class DefaultHandler
Throws:: SAXException

endElement

public void endElement(String namespaceURI,
                       String localName,
                       String qName)
                throws SAXException

endElement() is called by the parser when the /> or is encountered

Specified by:: endElement in interface ContentHandler
Overrides:: endElement in class DefaultHandler
Throws:: SAXException

Class XMLLoader

Constructor Summary

Method Summary

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

Methods inherited from class java.lang.Object

Constructor Detail

XMLLoader

Method Detail

load

startElement

endElement