Source code: ognl/PropertyAccessor.java
1 //--------------------------------------------------------------------------
2 // Copyright (c) 1998-2004, Drew Davidson and Luke Blanshard
3 // All rights reserved.
4 //
5 // Redistribution and use in source and binary forms, with or without
6 // modification, are permitted provided that the following conditions are
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14 // Neither the name of the Drew Davidson nor the names of its contributors
15 // may be used to endorse or promote products derived from this software
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30 //--------------------------------------------------------------------------
31 package ognl;
32
33 import java.util.Map;
34
35 /**
36 * This interface defines methods for setting and getting a property from a target object.
37 * A "property" in this case is a named data value that takes the generic form of an
38 * Object---the same definition as is used by beans. But the operational semantics of the
39 * term will vary by implementation of this interface: a bean-style implementation will
40 * get and set properties as beans do, by reflection on the target object's class, but
41 * other implementations are possible, such as one that uses the property name as a key
42 * into a map.
43 *
44 * <p> An implementation of this interface will often require that its target objects all
45 * be of some particular type. For example, the MapPropertyAccessor class requires that
46 * its targets all implement the java.util.Map interface.
47 *
48 * <p> Note that the "name" of a property is represented by a generic Object. Some
49 * implementations may require properties' names to be Strings, while others may allow
50 * them to be other types---for example, ArrayPropertyAccessor treats Number names as
51 * indexes into the target object, which must be an array.
52 * @author Luke Blanshard (blanshlu@netscape.net)
53 * @author Drew Davidson (drew@ognl.org)
54 */
55 public interface PropertyAccessor
56 {
57 /**
58 * Extracts and returns the property of the given name from the given target object.
59 * @param target the object to get the property from
60 * @param name the name of the property to get
61 * @return the current value of the given property in the given object
62 * @exception OgnlException if there is an error locating the property in the given object
63 */
64 Object getProperty( Map context, Object target, Object name ) throws OgnlException;
65
66 /**
67 * Sets the value of the property of the given name in the given target object.
68 * @param target the object to set the property in
69 * @param name the name of the property to set
70 * @param value the new value for the property
71 * @exception OgnlException if there is an error setting the property in the given object
72 */
73 void setProperty( Map context, Object target, Object name, Object value ) throws OgnlException;
74 }