ariba.util.expr
Interface PropertyAccessor

public interface PropertyAccessor

This interface defines methods for setting and getting a property from a target object. A "property" in this case is a named data value that takes the generic form of an Object---the same definition as is used by beans. But the operational semantics of the term will vary by implementation of this interface: a bean-style implementation will get and set properties as beans do, by reflection on the target object's class, but other implementations are possible, such as one that uses the property name as a key into a map.

An implementation of this interface will often require that its target objects all be of some particular type. For example, the MapPropertyAccessor class requires that its targets all implement the java.util.Map interface.

Note that the "name" of a property is represented by a generic Object. Some implementations may require properties' names to be Strings, while others may allow them to be other types---for example, ArrayPropertyAccessor treats Number names as indexes into the target object, which must be an array.

Author:

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

Method Summary

java.lang.Object	getProperty(java.util.Map context, java.lang.Object target, java.lang.Object name) Extracts and returns the property of the given name from the given target object.
void	setProperty(java.util.Map context, java.lang.Object target, java.lang.Object name, java.lang.Object value) Sets the value of the property of the given name in the given target object.

Method Detail

getProperty

java.lang.Object getProperty(java.util.Map context,
                             java.lang.Object target,
                             java.lang.Object name)
                             throws ExprException

Extracts and returns the property of the given name from the given target object.

Parameters:

target - the object to get the property from

name - the name of the property to get

Returns:

the current value of the given property in the given object

Throws:

ExprException - if there is an error locating the property in the given object

setProperty

void setProperty(java.util.Map context,
                 java.lang.Object target,
                 java.lang.Object name,
                 java.lang.Object value)
                 throws ExprException

Sets the value of the property of the given name in the given target object.

Parameters:

target - the object to set the property in

name - the name of the property to set

value - the new value for the property

Throws:

ExprException - if there is an error setting the property in the given object