org.apache.commons.beanutils

Class LazyDynaMap

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 Stringname
The name of this DynaClass (analogous to the getName() method of java.lang.Class).
protected booleanrestricted
Controls whether changes to this DynaClass's properties are allowed.
protected booleanreturnNull

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

Default is false.

Constructor Summary
LazyDynaMap()
Default Constructor.
LazyDynaMap(String name)
Construct a new LazyDynaMap with the specified name.
LazyDynaMap(Map values)
Construct a new LazyDynaMap with the specified Map.
LazyDynaMap(String name, Map values)
Construct a new LazyDynaMap with the specified name and Map.
LazyDynaMap(DynaProperty[] properties)
Construct a new LazyDynaMap with the specified properties.
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
Method Summary
voidadd(String name)
Add a new dynamic property with no restrictions on data type, readability, or writeability.
voidadd(String name, Class type)
Add a new dynamic property with the specified data type, but with no restrictions on readability or writeability.
voidadd(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.

protected voidadd(DynaProperty property)
Add a new dynamic property.
DynaProperty[]getDynaProperties()

Return an array of ProperyDescriptors for the properties currently defined in this DynaClass.

DynaPropertygetDynaProperty(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).

MapgetMap()
Return the underlying Map backing this DynaBean
StringgetName()
Return the name of this DynaClass (analogous to the getName() method of java.lang.Class
protected booleanisDynaProperty(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).

booleanisRestricted()

Is this DynaClass currently restricted.

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

booleanisReturnNull()
Should this DynaClass return a null from the getDynaProperty(name) method if the property doesn't exist.
DynaBeannewInstance()
Instantiate and return a new DynaBean instance, associated with this DynaClass.
voidremove(String name)
Remove the specified dynamic property, and any associated data type, readability, and writeability, from this dynamic class.
voidset(String name, Object value)
Set the value of a simple property with the specified name.
voidsetMap(Map values)
Set the Map backing this DynaBean
voidsetRestricted(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.

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

Field Detail

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 Detail

LazyDynaMap

public LazyDynaMap()
Default Constructor.

LazyDynaMap

public LazyDynaMap(String name)
Construct a new LazyDynaMap with the specified name.

Parameters: name Name of this DynaBean class

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, 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(DynaProperty[] properties)
Construct a new LazyDynaMap with the specified properties.

Parameters: properties Property descriptors for the supported properties

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

Method Detail

add

public void add(String name)
Add a new dynamic property with no restrictions on data type, readability, or writeability.

Parameters: name Name of the new dynamic property

Throws: IllegalArgumentException if name is null

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.

Parameters: name Name of the new dynamic property type Data type of the new dynamic property (null for no restrictions)

Throws: IllegalArgumentException if name is null IllegalStateException if this DynaClass is currently restricted, so no new properties can be added

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.

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

Throws: UnsupportedOperationException anytime this method is called

add

protected void add(DynaProperty property)
Add a new dynamic property.

Parameters: property Property the new dynamic property to add.

Throws: IllegalArgumentException if name is null

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?

Returns: the set of properties for this 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.

Parameters: name Name of the dynamic property for which a descriptor is requested

Returns: The descriptor for the specified property

Throws: IllegalArgumentException if no property name is specified

getMap

public Map getMap()
Return the underlying Map backing this DynaBean

Returns: the underlying Map

Since: 1.8.0

getName

public String getName()
Return the name of this DynaClass (analogous to the getName() method of java.lang.ClassReturns: the name of the 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).

Parameters: name Name of the dynamic property

Returns: true if the property exists, otherwise false

Throws: IllegalArgumentException if no property name is specified

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.

Returns: true if this Mutable DynaClass is restricted, otherwise false

isReturnNull

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

Returns: true if a null DynaProperty should be returned if the property doesn't exist, otherwise false if a new DynaProperty should be created.

newInstance

public DynaBean newInstance()
Instantiate and return a new DynaBean instance, associated with this DynaClass.

Returns: A new DynaBean instance

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.

Parameters: name Name of the dynamic property to remove

Throws: IllegalArgumentException if name is null IllegalStateException if this DynaClass is currently restricted, so no properties can be removed

set

public void set(String name, Object value)
Set the value of a simple property with the specified name.

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

Parameters: values The new Map of values

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.

Parameters: restricted The new restricted state

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.

Parameters: returnNull true if a null DynaProperty should be returned if the property doesn't exist, otherwise false if a new DynaProperty should be created.

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