org.apache.commons.beanutils
Class LazyDynaBean

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

All Implemented Interfaces:

Serializable, DynaBean

Direct Known Subclasses:

LazyDynaMap

public class LazyDynaBean
extends Object
implements DynaBean, Serializable

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.

Author:

Niall Pemberton

See Also:

LazyDynaClass, Serialized Form

Field Summary

protected static BigDecimal	BigDecimal_ZERO BigDecimal Zero
protected static BigInteger	BigInteger_ZERO BigInteger Zero
protected static Byte	Byte_ZERO Byte Zero
protected static Character	Character_SPACE Character Space
protected static Double	Double_ZERO Double Zero
protected MutableDynaClass	dynaClass The MutableDynaClass "base class" that this DynaBean is associated with.
protected static Float	Float_ZERO Float Zero
protected static Integer	Integer_ZERO Integer Zero
protected static Long	Long_ZERO Long Zero
protected static Short	Short_ZERO Short Zero
protected Map	values The MutableDynaClass "base class" that this DynaBean is associated with.

Constructor Summary

LazyDynaBean()
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.

LazyDynaBean(String name)
Construct a new LazyDynaBean with a LazyDynaClass instance.

Method Summary

boolean	contains(String name, String key) Does the specified mapped property contain a value for the specified key value?
protected Object	createDynaBeanProperty(String name, Class type) Create a new Instance of a 'DynaBean' Property.
protected Object	createIndexedProperty(String name, Class type) Create a new Instance of an 'Indexed' Property
protected Object	createMappedProperty(String name, Class type) Create a new Instance of a 'Mapped' Property
protected Object	createNumberProperty(String name, Class type) Create a new Instance of a java.lang.Number Property.
protected Object	createOtherProperty(String name, Class type) Create a new Instance of other Property types
protected Object	createPrimitiveProperty(String name, Class type) Create a new Instance of a 'Primitive' Property.
protected Object	createProperty(String name, Class type) Create a new Instance of a Property
protected Object	defaultIndexedProperty(String name) Creates a new ArrayList for an 'indexed' property which doesn't exist.
protected Map	defaultMappedProperty(String name) Creates a new HashMap for a 'mapped' property which doesn't exist.
Object	get(String name) Return the value of a simple property with the specified name.
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.
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.
protected Object	growIndexedProperty(String name, Object indexedProperty, int index) Grow the size of an indexed property
protected boolean	isAssignable(Class dest, Class source) Is an object of the source class assignable to the destination class?
protected boolean	isDynaProperty(String name) Indicates if there is a property with the specified name.
protected Map	newMap() Creates a new instance of the Map.
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, Object value) Set the value of a simple property with the specified name.
void	set(String name, String key, Object value) Set the value of a mapped property with the specified name.
int	size(String name) Return the size of an indexed or mapped property.

Methods inherited from class java.lang.Object

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

Field Detail

BigInteger_ZERO

protected static final BigInteger BigInteger_ZERO

BigInteger Zero

BigDecimal_ZERO

protected static final BigDecimal BigDecimal_ZERO

BigDecimal Zero

Character_SPACE

protected static final Character Character_SPACE

Character Space

Byte_ZERO

protected static final Byte Byte_ZERO

Byte Zero

Short_ZERO

protected static final Short Short_ZERO

Short Zero

Integer_ZERO

protected static final Integer Integer_ZERO

Integer Zero

Long_ZERO

protected static final Long Long_ZERO

Long Zero

Float_ZERO

protected static final Float Float_ZERO

Float Zero

Double_ZERO

protected static final Double Double_ZERO

Double Zero

values

protected Map values

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

dynaClass

protected MutableDynaClass dynaClass

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

Constructor Detail

LazyDynaBean

public LazyDynaBean()

Construct a new LazyDynaBean with a LazyDynaClass instance.

LazyDynaBean

public LazyDynaBean(String name)

Construct a new LazyDynaBean with a LazyDynaClass instance.

Parameters:

name - Name of this DynaBean class

LazyDynaBean

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

Method Detail

getMap

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

size

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

contains

public boolean contains(String name,
                        String key)

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

Specified by:

contains in interface DynaBean

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

get

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.

Specified by:

get in interface DynaBean

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

get

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.

Specified by:

get in interface DynaBean

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

get

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.

Specified by:

get in interface DynaBean

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

getDynaClass

public DynaClass getDynaClass()

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

Specified by:

getDynaClass in interface DynaBean

Returns:

The associated DynaClass

remove

public void remove(String name,
                   String key)

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

Specified by:

remove in interface DynaBean

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

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

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

set

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

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

Specified by:

set in interface DynaBean

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

set

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

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

Specified by:

set in interface DynaBean

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

growIndexedProperty

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)

createProperty

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

createIndexedProperty

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

createMappedProperty

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

createDynaBeanProperty

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

createPrimitiveProperty

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

createNumberProperty

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

createOtherProperty

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

defaultIndexedProperty

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)

defaultMappedProperty

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)

isDynaProperty

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

isAssignable

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

newMap

protected Map newMap()

Creates a new instance of the Map.

Returns:

a new Map instance