ognl

Class ObjectIndexedPropertyDescriptor

java.lang.Object

java.beans.FeatureDescriptor

java.beans.PropertyDescriptor

ognl.ObjectIndexedPropertyDescriptor

public class ObjectIndexedPropertyDescriptor
extends PropertyDescriptor

PropertyDescriptor subclass that describes an indexed set of read/write methods to get a property. Unlike IndexedPropertyDescriptor this allows the "key" to be an arbitrary object rather than just an int. Consequently it does not have a "readMethod" or "writeMethod" because it only expects a pattern like:

    public void setProperty(KeyType, ValueType);
    public ValueType getProperty(KeyType);

and does not require the methods that access it as an array. OGNL can get away with this without losing functionality because if the object does expose the properties they are most probably in a Map and that case is handled by the normal OGNL property accessors.

For example, if an object were to have methods that accessed and "attributes" property it would be natural to index them by String rather than by integer and expose the attributes as a map with a different property name:

    public void setAttribute(String name, Object value);
    public Object getAttribute(String name);
    public Map getAttributes();

Note that the index get/set is called get/set Attribute whereas the collection getter is called Attributes. This case is handled unambiguously by the OGNL property accessors because the set/getAttribute methods are detected by this object and the "attributes" case is handled by the MapPropertyAccessor. Therefore OGNL expressions calling this code would be handled in the following way:

OGNL Expression	Handling
attribute["name"]	Handled by an index getter, like getAttribute(String).
attribute["name"] = value	Handled by an index setter, like setAttribute(String, Object).
attributes["name"]	Handled by MapPropertyAccessor via a Map.get(). This will not go through the index get accessor.
attributes["name"] = value	Handled by MapPropertyAccessor via a Map.put(). This will not go through the index set accessor.

Author:

Luke Blanshard (blanshlu@netscape.net), Drew Davidson (drew@ognl.org)

Constructor Summary

Constructors

Constructor and Description
ObjectIndexedPropertyDescriptor(String propertyName, Class propertyType, Method indexedReadMethod, Method indexedWriteMethod)

Method Summary

Methods

Modifier and Type	Method and Description
Method	getIndexedReadMethod()
Method	getIndexedWriteMethod()
Class	getPropertyType()

Methods inherited from class java.beans.PropertyDescriptor

createPropertyEditor, equals, getPropertyEditorClass, getReadMethod, getWriteMethod, hashCode, isBound, isConstrained, setBound, setConstrained, setPropertyEditorClass, setReadMethod, setWriteMethod

Methods inherited from class java.beans.FeatureDescriptor

attributeNames, getDisplayName, getName, getShortDescription, getValue, isExpert, isHidden, isPreferred, setDisplayName, setExpert, setHidden, setName, setPreferred, setShortDescription, setValue, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ObjectIndexedPropertyDescriptor

public ObjectIndexedPropertyDescriptor(String propertyName,
                               Class propertyType,
                               Method indexedReadMethod,
                               Method indexedWriteMethod)
                                throws IntrospectionException

Throws:

IntrospectionException

Method Detail

getIndexedReadMethod

public Method getIndexedReadMethod()

getIndexedWriteMethod

public Method getIndexedWriteMethod()

getPropertyType

public Class getPropertyType()

Overrides:

getPropertyType in class PropertyDescriptor