org.apache.commons.beanutils
Class DynaBeanMapDecorator

java.lang.Object
  org.apache.commons.beanutils.DynaBeanMapDecorator

All Implemented Interfaces:

Map

public class DynaBeanMapDecorator
extends Object
implements Map

Decorates a DynaBean to provide Map behaviour.

The motivation for this implementation is to provide access to DynaBean properties in technologies that are unaware of BeanUtils and DynaBeans - such as the expression languages of JSTL and JSF.

This can be achieved either by wrapping the DynaBean prior to providing it to the technolody to process or by providing a Map accessor method on the DynaBean implementation:

         public Map getMap() {
             return new DynaBeanMapDecorator(this);
         }

This, for example, could be used in JSTL in the following way to access a DynaBean's fooProperty:

• ${myDynaBean.map.fooProperty}

Usage

To decorate a DynaBean simply instantiate this class with the target DynaBean:

• Map fooMap = new DynaBeanMapDecorator(fooDynaBean);

The above example creates a read only Map. To create a Map which can be modified, construct a DynaBeanMapDecorator with the read only attribute set to false:

• Map fooMap = new DynaBeanMapDecorator(fooDynaBean, false);

Limitations

In this implementation the entrySet(), keySet() and values() methods create an unmodifiable Set and it does not support the Map's clear() and remove() operations.

Since:

BeanUtils 1.8.0

Version:

$Revision: 546471 $ $Date: 2007-06-12 13:57:20 +0100 (Tue, 12 Jun 2007) $

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry

Constructor Summary

DynaBeanMapDecorator(DynaBean dynaBean)
Constructs a read only Map for the specified DynaBean.

DynaBeanMapDecorator(DynaBean dynaBean, boolean readOnly)
Construct a Map for the specified DynaBean.

Method Summary

void	clear() clear() operation is not supported.
boolean	containsKey(Object key) Indicate whether the DynaBean contains a specified value for one (or more) of its properties.
boolean	containsValue(Object value) Indicates whether the decorated DynaBean contains a specified value.
Set	entrySet() Returns the Set of the property/value mappings in the decorated DynaBean.
Object	get(Object key) Return the value for the specified key from the decorated DynaBean.
DynaBean	getDynaBean() Provide access to the underlying DynaBean this Map decorates.
boolean	isEmpty() Indicate whether the decorated DynaBean has any properties.
boolean	isReadOnly() Indicate whether the Map is read only.
Set	keySet() Returns the Set of the property names in the decorated DynaBean.
Object	put(Object key, Object value) Set the value for the specified property in the decorated DynaBean.
void	putAll(Map map) Copy the contents of a Map to the decorated DynaBean.
Object	remove(Object key) remove() operation is not supported.
int	size() Returns the number properties in the decorated DynaBean.
Collection	values() Returns the set of property values in the decorated DynaBean.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Map

equals, hashCode

Constructor Detail

DynaBeanMapDecorator

public DynaBeanMapDecorator(DynaBean dynaBean)

Constructs a read only Map for the specified DynaBean.

Parameters:

dynaBean - The dyna bean being decorated

Throws:

IllegalArgumentException - if the DynaBean is null.

DynaBeanMapDecorator

public DynaBeanMapDecorator(DynaBean dynaBean,
                            boolean readOnly)

Construct a Map for the specified DynaBean.

Parameters:

dynaBean - The dyna bean being decorated

readOnly - true if the Mpa is read only otherwise false

Throws:

IllegalArgumentException - if the DynaBean is null.

Method Detail

isReadOnly

public boolean isReadOnly()

Indicate whether the Map is read only.

Returns:

true if the Map is read only, otherwise false.

clear

public void clear()

clear() operation is not supported.

Specified by:

clear in interface Map

Throws:

UnsupportedOperationException

containsKey

public boolean containsKey(Object key)

Indicate whether the DynaBean contains a specified value for one (or more) of its properties.

Specified by:

containsKey in interface Map

Parameters:

key - The DynaBean's property name

Returns:

true if one of the DynaBean's properties contains a specified value.

containsValue

public boolean containsValue(Object value)

Indicates whether the decorated DynaBean contains a specified value.

Specified by:

containsValue in interface Map

Parameters:

value - The value to check for.

Returns:

true if one of the the DynaBean's properties contains the specified value, otherwise false.

entrySet

public Set entrySet()

Returns the Set of the property/value mappings in the decorated DynaBean.

Each element in the Set is a Map.Entry type.

Specified by:

entrySet in interface Map

Returns:

An unmodifiable set of the DynaBean property name/value pairs

get

public Object get(Object key)

Return the value for the specified key from the decorated DynaBean.

Specified by:

get in interface Map

Parameters:

key - The DynaBean's property name

Returns:

The value for the specified property.

isEmpty

public boolean isEmpty()

Indicate whether the decorated DynaBean has any properties.

Specified by:

isEmpty in interface Map

Returns:

true if the DynaBean has no properties, otherwise false.

keySet

public Set keySet()

Returns the Set of the property names in the decorated DynaBean.

N.B.For DynaBeans whose associated DynaClass is a MutableDynaClass a new Set is created every time, otherwise the Set is created only once and cached.

Specified by:

keySet in interface Map

Returns:

An unmodifiable set of the DynaBeans property names.

put

public Object put(Object key,
                  Object value)

Set the value for the specified property in the decorated DynaBean.

Specified by:

put in interface Map

Parameters:

key - The DynaBean's property name

value - The value for the specified property.

Returns:

The previous property's value.

Throws:

UnsupportedOperationException - if isReadOnly() is true.

putAll

public void putAll(Map map)

Copy the contents of a Map to the decorated DynaBean.

Specified by:

putAll in interface Map

Parameters:

map - The Map of values to copy.

Throws:

UnsupportedOperationException - if isReadOnly() is true.

remove

public Object remove(Object key)

remove() operation is not supported.

Specified by:

remove in interface Map

Parameters:

key - The DynaBean's property name

Returns:

the value removed

Throws:

UnsupportedOperationException

size

public int size()

Returns the number properties in the decorated DynaBean.

Specified by:

size in interface Map

Returns:

The number of properties.

values

public Collection values()

Returns the set of property values in the decorated DynaBean.

Specified by:

values in interface Map

Returns:

Unmodifiable collection of values.

getDynaBean

public DynaBean getDynaBean()

Provide access to the underlying DynaBean this Map decorates.

Returns:

the decorated DynaBean.