public class

LazyDynaBean

extends Object
implements Serializable DynaBean
java.lang.Object
   ↳ org.apache.commons.beanutils.LazyDynaBean
Known Direct Subclasses

Class Overview

DynaBean which automatically adds properties to the DynaClass and provides Lazy List and Lazy Map features.

DynaBeans deal with three types of properties - simple, indexed and mapped and have the following get() and set() methods for each of these types:

  • Simple property methods - get(name) and set(name, value)
  • Indexed property methods - get(name, index) and set(name, index, value)
  • Mapped property methods - get(name, key) and set(name, key, value)

Getting Property Values

Calling any of the get() methods, for a property which doesn't exist, returns null in this implementation.

Setting Simple Properties

The LazyDynaBean will automatically add a property to the DynaClass if it doesn't exist when the set(name, value) method is called.

DynaBean myBean = new LazyDynaBean();
myBean.set("myProperty", "myValue");

Setting Indexed Properties

If the property doesn't exist, the LazyDynaBean will automatically add a property with an ArrayList type to the DynaClass when the set(name, index, value) method is called. It will also instantiate a new ArrayList and automatically grow the List so that it is big enough to accomodate the index being set. ArrayList is the default indexed property that LazyDynaBean uses but this can be easily changed by overriding the defaultIndexedProperty(name) method.

DynaBean myBean = new LazyDynaBean();
myBean.set("myIndexedProperty", 0, "myValue1");
myBean.set("myIndexedProperty", 1, "myValue2");

If the indexed property does exist in the DynaClass but is set to null in the LazyDynaBean, then it will instantiate a new List or Array as specified by the property's type in the DynaClass and automatically grow the List or Array so that it is big enough to accomodate the index being set.

DynaBean myBean = new LazyDynaBean();
MutableDynaClass myClass = (MutableDynaClass)myBean.getDynaClass();
myClass.add("myIndexedProperty", int[].class);
myBean.set("myIndexedProperty", 0, new Integer(10));
myBean.set("myIndexedProperty", 1, new Integer(20));

Setting Mapped Properties

If the property doesn't exist, the LazyDynaBean will automatically add a property with a HashMap type to the DynaClass and instantiate a new HashMap in the DynaBean when the set(name, key, value) method is called. HashMap is the default mapped property that LazyDynaBean uses but this can be easily changed by overriding the defaultMappedProperty(name) method.

DynaBean myBean = new LazyDynaBean();
myBean.set("myMappedProperty", "myKey", "myValue");

If the mapped property does exist in the DynaClass but is set to null in the LazyDynaBean, then it will instantiate a new Map as specified by the property's type in the DynaClass.

DynaBean myBean = new LazyDynaBean();
MutableDynaClass myClass = (MutableDynaClass)myBean.getDynaClass();
myClass.add("myMappedProperty", TreeMap.class);
myBean.set("myMappedProperty", "myKey", "myValue");

Restricted DynaClass

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.

See Also

Summary

Fields
protected static final BigDecimal BigDecimal_ZERO BigDecimal Zero
protected static final BigInteger BigInteger_ZERO BigInteger Zero
protected static final Byte Byte_ZERO Byte Zero
protected static final Character Character_SPACE Character Space
protected static final Double Double_ZERO Double Zero
protected static final Float Float_ZERO Float Zero
protected static final Integer Integer_ZERO Integer Zero
protected static final Long Long_ZERO Long Zero
protected static final Short Short_ZERO Short Zero
protected MutableDynaClass dynaClass The MutableDynaClass "base class" that this DynaBean is associated with.
protected Map values The MutableDynaClass "base class" that this DynaBean is associated with.
Public Constructors
LazyDynaBean()
Construct a new LazyDynaBean with a LazyDynaClass instance.
LazyDynaBean(String name)
Construct a new LazyDynaBean with a LazyDynaClass instance.
LazyDynaBean(DynaClass dynaClass)
Construct a new DynaBean associated with the specified DynaClass instance - if its not a MutableDynaClass then a new LazyDynaClass is created and the properties copied.
Public Methods
boolean contains(String name, String key)
Does the specified mapped property contain a value for the specified key value?
Object get(String name, int index)

Return the value of an indexed property with the specified name.

Object get(String name, String key)

Return the value of a mapped property with the specified name.

Object get(String name)

Return the value of a simple property with the specified name.

DynaClass getDynaClass()
Return the DynaClass instance that describes the set of properties available for this DynaBean.
Map getMap()
Return a Map representation of this DynaBean.
void remove(String name, String key)
Remove any existing value for the specified key on the specified mapped property.
void set(String name, int index, Object value)
Set the value of an indexed property with the specified name.
void set(String name, String key, Object value)
Set the value of a mapped property with the specified name.
void set(String name, Object value)
Set the value of a simple property with the specified name.
int size(String name)

Return the size of an indexed or mapped property.

Protected Methods
Object createDynaBeanProperty(String name, Class type)
Create a new Instance of a 'DynaBean' Property.
Object createIndexedProperty(String name, Class type)
Create a new Instance of an 'Indexed' Property
Object createMappedProperty(String name, Class type)
Create a new Instance of a 'Mapped' Property
Object createNumberProperty(String name, Class type)
Create a new Instance of a java.lang.Number Property.
Object createOtherProperty(String name, Class type)
Create a new Instance of other Property types
Object createPrimitiveProperty(String name, Class type)
Create a new Instance of a 'Primitive' Property.
Object createProperty(String name, Class type)
Create a new Instance of a Property
Object defaultIndexedProperty(String name)

Creates a new ArrayList for an 'indexed' property which doesn't exist.

Map defaultMappedProperty(String name)

Creates a new HashMap for a 'mapped' property which doesn't exist.

Object growIndexedProperty(String name, Object indexedProperty, int index)
Grow the size of an indexed property
boolean isAssignable(Class dest, Class source)
Is an object of the source class assignable to the destination class?
boolean isDynaProperty(String name)
Indicates if there is a property with the specified name.
Map newMap()

Creates a new instance of the Map.

[Expand]
Inherited Methods
From class java.lang.Object
From interface org.apache.commons.beanutils.DynaBean

Fields

protected static final BigDecimal BigDecimal_ZERO

BigDecimal Zero

protected static final BigInteger BigInteger_ZERO

BigInteger Zero

protected static final Byte Byte_ZERO

Byte Zero

protected static final Character Character_SPACE

Character Space

protected static final Double Double_ZERO

Double Zero

protected static final Float Float_ZERO

Float Zero

protected static final Integer Integer_ZERO

Integer Zero

protected static final Long Long_ZERO

Long Zero

protected static final Short Short_ZERO

Short Zero

protected MutableDynaClass dynaClass

The MutableDynaClass "base class" that this DynaBean is associated with.

protected Map values

The MutableDynaClass "base class" that this DynaBean is associated with.

Public Constructors

public LazyDynaBean ()

Construct a new LazyDynaBean with a LazyDynaClass instance.

public LazyDynaBean (String name)

Construct a new LazyDynaBean with a LazyDynaClass instance.

Parameters
name Name of this DynaBean class

public LazyDynaBean (DynaClass dynaClass)

Construct a new DynaBean associated with the specified DynaClass instance - if its not a MutableDynaClass then a new LazyDynaClass is created and the properties copied.

Parameters
dynaClass The DynaClass we are associated with

Public Methods

public boolean contains (String name, String key)

Does the specified mapped property contain a value for the specified key value?

Parameters
name Name of the property to check
key Name of the key to check
Returns
  • true if the mapped property contains a value for the specified key, otherwise false
Throws
IllegalArgumentException if no property name is specified

public Object get (String name, int index)

Return the value of an indexed property with the specified name.

N.B. Returns null if there is no 'indexed' property of the specified name.

Parameters
name Name of the property whose value is to be retrieved
index Index of the value to be retrieved
Returns
  • The indexed property's value
Throws
IllegalArgumentException if the specified property exists, but is not indexed
IndexOutOfBoundsException if the specified index is outside the range of the underlying property

public Object get (String name, String key)

Return the value of a mapped property with the specified name.

N.B. Returns null if there is no 'mapped' property of the specified name.

Parameters
name Name of the property whose value is to be retrieved
key Key of the value to be retrieved
Returns
  • The mapped property's value
Throws
IllegalArgumentException if the specified property exists, but is not mapped

public Object get (String name)

Return the value of a simple property with the specified name.

N.B. Returns null if there is no property of the specified name.

Parameters
name Name of the property whose value is to be retrieved.
Returns
  • The property's value
Throws
IllegalArgumentException if no property name is specified

public DynaClass getDynaClass ()

Return the DynaClass instance that describes the set of properties available for this DynaBean.

Returns
  • The associated DynaClass

public Map getMap ()

Return a Map representation of this DynaBean.

This, for example, could be used in JSTL in the following way to access a DynaBean's fooProperty:
  • ${myDynaBean.map.fooProperty}

Returns
  • a Map representation of this DynaBean

public void remove (String name, String key)

Remove any existing value for the specified key on the specified mapped property.

Parameters
name Name of the property for which a value is to be removed
key Key of the value to be removed
Throws
IllegalArgumentException if there is no property of the specified name

public void set (String name, int index, Object value)

Set the value of an indexed property with the specified name.

Parameters
name Name of the property whose value is to be set
index Index of the property to be set
value Value to which this property is to be set
Throws
ConversionException if the specified value cannot be converted to the type required for this property
IllegalArgumentException if there is no property of the specified name
IllegalArgumentException if the specified property exists, but is not indexed
IndexOutOfBoundsException if the specified index is outside the range of the underlying property

public void set (String name, String key, Object value)

Set the value of a mapped property with the specified name.

Parameters
name Name of the property whose value is to be set
key Key of the property to be set
value Value to which this property is to be set
Throws
ConversionException if the specified value cannot be converted to the type required for this property
IllegalArgumentException if there is no property of the specified name
IllegalArgumentException if the specified property exists, but is not mapped

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
Throws
IllegalArgumentException if this is not an existing property name for our DynaClass and the MutableDynaClass is restricted
ConversionException if the specified value cannot be converted to the type required for this property
NullPointerException if an attempt is made to set a primitive property to null

public int size (String name)

Return the size of an indexed or mapped property.

Parameters
name Name of the property
Returns
  • The indexed or mapped property size
Throws
IllegalArgumentException if no property name is specified

Protected Methods

protected Object createDynaBeanProperty (String name, Class type)

Create a new Instance of a 'DynaBean' Property.

Parameters
name The name of the property
type The class of the property
Returns
  • The new value

protected Object createIndexedProperty (String name, Class type)

Create a new Instance of an 'Indexed' Property

Parameters
name The name of the property
type The class of the property
Returns
  • The new value

protected Object createMappedProperty (String name, Class type)

Create a new Instance of a 'Mapped' Property

Parameters
name The name of the property
type The class of the property
Returns
  • The new value

protected Object createNumberProperty (String name, Class type)

Create a new Instance of a java.lang.Number Property.

Parameters
name The name of the property
type The class of the property
Returns
  • The new value

protected Object createOtherProperty (String name, Class type)

Create a new Instance of other Property types

Parameters
name The name of the property
type The class of the property
Returns
  • The new value

protected Object createPrimitiveProperty (String name, Class type)

Create a new Instance of a 'Primitive' Property.

Parameters
name The name of the property
type The class of the property
Returns
  • The new value

protected Object createProperty (String name, Class type)

Create a new Instance of a Property

Parameters
name The name of the property
type The class of the property
Returns
  • The new value

protected Object defaultIndexedProperty (String name)

Creates a new ArrayList for an 'indexed' property which doesn't exist.

This method shouls be overriden if an alternative List or Array implementation is required for 'indexed' properties.

Parameters
name Name of the 'indexed property.
Returns
  • The default value for an indexed property (java.util.ArrayList)

protected Map defaultMappedProperty (String name)

Creates a new HashMap for a 'mapped' property which doesn't exist.

This method can be overriden if an alternative Map implementation is required for 'mapped' properties.

Parameters
name Name of the 'mapped property.
Returns
  • The default value for a mapped property (java.util.HashMap)

protected Object growIndexedProperty (String name, Object indexedProperty, int index)

Grow the size of an indexed property

Parameters
name The name of the property
indexedProperty The current property value
index The indexed value to grow the property to (i.e. one less than the required size)
Returns
  • The new property value (grown to the appropriate size)

protected boolean isAssignable (Class dest, Class source)

Is an object of the source class assignable to the destination class?

Parameters
dest Destination class
source Source class
Returns
  • true if the source class is assignable to the destination class, otherwise false

protected boolean isDynaProperty (String name)

Indicates if there is a property with the specified name.

Parameters
name The name of the property to check
Returns
  • true if there is a property of the specified name, otherwise false

protected Map newMap ()

Creates a new instance of the Map.

Returns
  • a new Map instance