org.apache.commons.beanutils

Class LazyDynaMap

Implemented Interfaces:
DynaBean, DynaClass, MutableDynaClass, Serializable

public class LazyDynaMap
extends LazyDynaBean
implements MutableDynaClass

Provides a light weight DynaBean facade to a Map with lazy map/list processing.

Its a light weight DynaBean implementation because there is no actual DynaClass associated with this DynaBean - in fact it implements the DynaClass interface itself providing pseudo DynaClass behaviour from the actual values stored in the Map.

As well providing rhe standard DynaBean access to the Map's properties this class also provides the usual Lazy behaviour:

Restricted DynaClass

This class implements the MutableDynaClass interface. MutableDynaClass have a facility to restrict the DynaClass so that its properties cannot be modified. If the MutableDynaClass is restricted then calling any of the set() methods for a property which doesn't exist will result in a IllegalArgumentException being thrown.

Author:
Niall Pemberton

Field Summary

protected String
name
The name of this DynaClass (analogous to the getName() method of java.lang.Class).
protected boolean
restricted
Controls whether changes to this DynaClass's properties are allowed.
protected boolean
returnNull
Controls whether the getDynaProperty() method returns null if a property doesn't exist - or creates a new one.

Fields inherited from class org.apache.commons.beanutils.LazyDynaBean

BigDecimal_ZERO, BigInteger_ZERO, Byte_ZERO, Character_SPACE, Double_ZERO, Float_ZERO, Integer_ZERO, Long_ZERO, Short_ZERO, dynaClass, logger, values

Constructor Summary

LazyDynaMap()
Default Constructor.
LazyDynaMap(Map values)
Construct a new LazyDynaMap with the specified Map.
LazyDynaMap(String name)
Construct a new LazyDynaMap with the specified name.
LazyDynaMap(String name, Map values)
Construct a new LazyDynaMap with the specified name and Map.
LazyDynaMap(String name, DynaProperty[] properties)
Construct a new LazyDynaMap with the specified name and properties.
LazyDynaMap(DynaClass dynaClass)
Construct a new LazyDynaMap based on an exisiting DynaClass
LazyDynaMap(DynaProperty[] properties)
Construct a new LazyDynaMap with the specified properties.

Method Summary

void
add(String name)
Add a new dynamic property with no restrictions on data type, readability, or writeability.
void
add(String name, Class type)
Add a new dynamic property with the specified data type, but with no restrictions on readability or writeability.
void
add(String name, Class type, boolean readable, boolean writeable)
Add a new dynamic property with the specified data type, readability, and writeability.
protected void
add(DynaProperty property)
Add a new dynamic property.
DynaProperty[]
getDynaProperties()
Return an array of ProperyDescriptors for the properties currently defined in this DynaClass.
DynaProperty
getDynaProperty(String name)
Return a property descriptor for the specified property.
String
getName()
Return the name of this DynaClass (analogous to the getName() method of java.lang.Class
protected boolean
isDynaProperty(String name)
Indicate whether a property actually exists.
boolean
isRestricted()
Is this DynaClass currently restricted.
boolean
isReturnNull()
Should this DynaClass return a null from the getDynaProperty(name) method if the property doesn't exist.
DynaBean
newInstance()
Instantiate and return a new DynaBean instance, associated with this DynaClass.
void
remove(String name)
Remove the specified dynamic property, and any associated data type, readability, and writeability, from this dynamic class.
void
set(String name, Object value)
Set the value of a simple property with the specified name.
void
setMap(Map values)
Set the Map backing this DynaBean
void
setRestricted(boolean restricted)
Set whether this DynaClass is currently restricted.
void
setReturnNull(boolean returnNull)
Set whether this DynaClass should return a null from the getDynaProperty(name) method if the property doesn't exist.

Methods inherited from class org.apache.commons.beanutils.LazyDynaBean

contains, createDynaBeanProperty, createIndexedProperty, createMappedProperty, createNumberProperty, createOtherProperty, createPrimitiveProperty, createProperty, defaultIndexedProperty, defaultMappedProperty, get, get, get, getDynaClass, getMap, growIndexedProperty, isAssignable, isDynaProperty, newMap, remove, set, set, set, size

Field Details

name

protected String name
The name of this DynaClass (analogous to the getName() method of java.lang.Class).

restricted

protected boolean restricted
Controls whether changes to this DynaClass's properties are allowed.

returnNull

protected boolean returnNull
Controls whether the getDynaProperty() method returns null if a property doesn't exist - or creates a new one.

Default is false.

Constructor Details

LazyDynaMap

public LazyDynaMap()
Default Constructor.

LazyDynaMap

public LazyDynaMap(Map values)
Construct a new LazyDynaMap with the specified Map.
Parameters:
values - The Map backing this LazyDynaMap

LazyDynaMap

public LazyDynaMap(String name)
Construct a new LazyDynaMap with the specified name.
Parameters:
name - Name of this DynaBean class

LazyDynaMap

public LazyDynaMap(String name,
                   Map values)
Construct a new LazyDynaMap with the specified name and Map.
Parameters:
name - Name of this DynaBean class
values - The Map backing this LazyDynaMap

LazyDynaMap

public LazyDynaMap(String name,
                   DynaProperty[] properties)
Construct a new LazyDynaMap with the specified name and properties.
Parameters:
name - Name of this DynaBean class
properties - Property descriptors for the supported properties

LazyDynaMap

public LazyDynaMap(DynaClass dynaClass)
Construct a new LazyDynaMap based on an exisiting DynaClass
Parameters:
dynaClass - DynaClass to copy the name and properties from

LazyDynaMap

public LazyDynaMap(DynaProperty[] properties)
Construct a new LazyDynaMap with the specified properties.
Parameters:
properties - Property descriptors for the supported properties

Method Details

add

public void add(String name)
Add a new dynamic property with no restrictions on data type, readability, or writeability.
Specified by:
add in interface MutableDynaClass
Parameters:
name - Name of the new dynamic property

add

public void add(String name,
                Class type)
Add a new dynamic property with the specified data type, but with no restrictions on readability or writeability.
Specified by:
add in interface MutableDynaClass
Parameters:
name - Name of the new dynamic property
type - Data type of the new dynamic property (null for no restrictions)

add

public void add(String name,
                Class type,
                boolean readable,
                boolean writeable)
Add a new dynamic property with the specified data type, readability, and writeability.

N.B.Support for readable/writeable properties has not been implemented and this method always throws a UnsupportedOperationException.

I'm not sure the intention of the original authors for this method, but it seems to me that readable/writable should be attributes of the DynaProperty class (which they are not) and is the reason this method has not been implemented.

Specified by:
add in interface MutableDynaClass
Parameters:
name - Name of the new dynamic property
type - Data type of the new dynamic property (null for no restrictions)
readable - Set to true if this property value should be readable
writeable - Set to true if this property value should be writeable

add

protected void add(DynaProperty property)
Add a new dynamic property.
Parameters:
property - Property the new dynamic property to add.

getDynaProperties

public DynaProperty[] getDynaProperties()
Return an array of ProperyDescriptors for the properties currently defined in this DynaClass. If no properties are defined, a zero-length array will be returned.

FIXME - Should we really be implementing getBeanInfo() instead, which returns property descriptors and a bunch of other stuff?

Specified by:
getDynaProperties in interface DynaClass

getDynaProperty

public DynaProperty getDynaProperty(String name)
Return a property descriptor for the specified property.

If the property is not found and the returnNull indicator is true, this method always returns null.

If the property is not found and the returnNull indicator is false a new property descriptor is created and returned (although its not actually added to the DynaClass's properties). This is the default beahviour.

The reason for not returning a null property descriptor is that BeanUtils uses this method to check if a property exists before trying to set it - since these Map implementations automatically add any new properties when they are set, returning null from this method would defeat their purpose.

Specified by:
getDynaProperty in interface DynaClass
Parameters:
name - Name of the dynamic property for which a descriptor is requested

getName

public String getName()
Return the name of this DynaClass (analogous to the getName() method of java.lang.Class
Specified by:
getName in interface DynaClass

isDynaProperty

protected boolean isDynaProperty(String name)
Indicate whether a property actually exists.

N.B. Using getDynaProperty(name) == null doesn't work in this implementation because that method might return a DynaProperty if it doesn't exist (depending on the returnNull indicator).

Overrides:
isDynaProperty in interface LazyDynaBean

isRestricted

public boolean isRestricted()
Is this DynaClass currently restricted.

If restricted, no changes to the existing registration of property names, data types, readability, or writeability are allowed.

Specified by:
isRestricted in interface MutableDynaClass

isReturnNull

public boolean isReturnNull()
Should this DynaClass return a null from the getDynaProperty(name) method if the property doesn't exist.

newInstance

public DynaBean newInstance()
Instantiate and return a new DynaBean instance, associated with this DynaClass.
Specified by:
newInstance in interface DynaClass

remove

public void remove(String name)
Remove the specified dynamic property, and any associated data type, readability, and writeability, from this dynamic class. NOTE - This does NOT cause any corresponding property values to be removed from DynaBean instances associated with this DynaClass.
Specified by:
remove in interface MutableDynaClass
Parameters:
name - Name of the dynamic property to remove

set

public void set(String name,
                Object value)
Set the value of a simple property with the specified name.
Specified by:
set in interface DynaBean
Overrides:
set in interface LazyDynaBean
Parameters:
name - Name of the property whose value is to be set
value - Value to which this property is to be set

setMap

public void setMap(Map values)
Set the Map backing this DynaBean

setRestricted

public void setRestricted(boolean restricted)
Set whether this DynaClass is currently restricted.

If restricted, no changes to the existing registration of property names, data types, readability, or writeability are allowed.

Specified by:
setRestricted in interface MutableDynaClass

setReturnNull

public void setReturnNull(boolean returnNull)
Set whether this DynaClass should return a null from the getDynaProperty(name) method if the property doesn't exist.

Copyright (c) 2001-2004 - Apache Software Foundation