org.apache.commons.beanutils
Class LazyDynaClass
- DynaClass, MutableDynaClass, Serializable
public class LazyDynaClass
DynaClass which implements the
MutableDynaClass
interface.
A
MutableDynaClass
is a specialized extension to
DynaClass
that allows properties to be added or removed dynamically.
This implementation has one slightly unusual default behaviour - calling
the
getDynaProperty(name)
method for a property which doesn't
exist returns a
DynaProperty
rather than
null
. The
reason for this is that
BeanUtils
calls this method to check if
a property exists before trying to set the value. This would defeat the object
of the
LazyDynaBean
which automatically adds missing properties
when any of its
set()
methods are called. For this reason the
isDynaProperty(name)
method has been added to this implementation
in order to determine if a property actually exists. If the more
normal
behaviour of returning
null
is required, then this can be achieved
by calling the
setReturnNull(true)
.
The
add(name, type, readable, writable)
method is not implemented
and always throws an
UnsupportedOperationException
. I believe
this attributes need to be added to the
DynaProperty
class
in order to control read/write facilities.
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.
|
LazyDynaClass() - Construct a new LazyDynaClass with default parameters.
|
LazyDynaClass(String name) - Construct a new LazyDynaClass with the specified name.
|
LazyDynaClass(String name, Class dynaBeanClass) - Construct a new LazyDynaClass with the specified name and DynaBean class.
|
LazyDynaClass(String name, Class dynaBeanClass, properties[] ) - Construct a new LazyDynaClass with the specified name, DynaBean class and properties.
|
LazyDynaClass(String name, DynaProperty[] properties) - Construct a new LazyDynaClass with the specified name and properties.
|
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 | getDynaProperty(String name) - Return a property descriptor for the specified property.
|
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.
|
void | remove(String name) - Remove the specified dynamic property, and any associated data type,
readability, and writeability, from this dynamic class.
|
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.
|
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
.
LazyDynaClass
public LazyDynaClass()
Construct a new LazyDynaClass with default parameters.
LazyDynaClass
public LazyDynaClass(String name)
Construct a new LazyDynaClass with the specified name.
name
- Name of this DynaBean class
LazyDynaClass
public LazyDynaClass(String name,
Class dynaBeanClass)
Construct a new LazyDynaClass with the specified name and DynaBean class.
name
- Name of this DynaBean classdynaBeanClass
- The implementation class for new instances
LazyDynaClass
public LazyDynaClass(String name,
Class dynaBeanClass,
properties[] )
Construct a new LazyDynaClass with the specified name, DynaBean class and properties.
name
- Name of this DynaBean classdynaBeanClass
- The implementation class for new intances
LazyDynaClass
public LazyDynaClass(String name,
DynaProperty[] properties)
Construct a new LazyDynaClass with the specified name and properties.
name
- Name of this DynaBean classproperties
- Property descriptors for the supported properties
add
public void add(String name)
Add a new dynamic property with no restrictions on data type,
readability, or writeability.
- add in interface MutableDynaClass
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.
- add in interface MutableDynaClass
name
- Name of the new dynamic propertytype
- 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.
- add in interface MutableDynaClass
name
- Name of the new dynamic propertytype
- Data type of the new dynamic property (null for no
restrictions)readable
- Set to true
if this property value
should be readablewriteable
- Set to true
if this property value
should be writeable
add
protected void add(DynaProperty property)
Add a new dynamic property.
property
- Property the new dynamic property to add.
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
Lazy implementations automatically
add any new properties when they are set, returning
null
from
this method would defeat their purpose.
- getDynaProperty in interface DynaClass
- getDynaProperty in interface BasicDynaClass
name
- Name of the dynamic property for which a descriptor
is requested
isDynaProperty
public 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).
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.
- 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.
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.
- remove in interface MutableDynaClass
name
- Name of the dynamic property to remove
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.
- 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