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// --------------------------------------------------------------------------
// Copyright (c) 1998-2004, Drew Davidson and Luke Blanshard
// All rights reserved.
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package com.feilong.lib.ognl;
import java.util.Map;
/**
* 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 ([email protected])
* @author Drew Davidson ([email protected])
*/
public interface PropertyAccessor{
/**
* Extracts and returns the property of the given name from the given target object.
*
* @param context
* The current execution context.
* @param target
* the object to get the property from
* @param name
* the name of the property to get.
*
* @return the current value of the given property in the given object
* @exception OgnlException
* if there is an error locating the property in the given object
*/
Object getProperty(Map context,Object target,Object name) throws OgnlException;
/**
* Sets the value of the property of the given name in the given target object.
*
* @param context
* The current execution context.
* @param target
* the object to set the property in
* @param name
* the name of the property to set
* @param value
* the new value for the property.
*
* @exception OgnlException
* if there is an error setting the property in the given object
*/
void setProperty(Map context,Object target,Object name,Object value) throws OgnlException;
/**
* Returns a java string representing the textual method that should be called to access a
* particular element. (ie "get")
*
* @param context
* The current execution context.
* @param target
* The current object target on the expression tree being evaluated.
* @param index
* The index object that will be placed inside the string to access the value.
*
* @return The source accessor method to call.
*/
String getSourceAccessor(OgnlContext context,Object target,Object index);
/**
* Returns a java string representing the textual method that should be called to set a
* particular element. (ie "set")
*
* @param context
* The current execution context.
* @param target
* The current object target on the expression tree being evaluated.
* @param index
* The index object that will be placed inside the string to set the value.
* @return The source setter method to call.
*/
String getSourceSetter(OgnlContext context,Object target,Object index);
}