Package org.apache.commons.beanutils2

Class LazyDynaBean

java.lang.Object
org.apache.commons.beanutils2.LazyDynaBean
All Implemented Interfaces:
DynaBean
Direct Known Subclasses:
LazyDynaMap
public class LazyDynaBean extends Object implements DynaBean

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()</code> and <code>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</code> will automatically add a property to the <code>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</code> type to the <code>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 accommodate 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</code> in the <code>LazyDynaBean, then it will instantiate a new List</code> or <code>Array as specified by the property's type in the DynaClass</code> and automatically <em>grow</em> the <code>List or Array so that it is big enough to accommodate the index being set.


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

Setting Mapped Properties

If the property doesn't exist, the LazyDynaBean will automatically add a property with a HashMap</code> type to the <code>DynaClass and instantiate a new HashMap in the DynaBean when the set(name, key, value)</code> method is called. <code>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</code> in the <code>LazyDynaBean, then it will instantiate a new Map</code> as specified by the property's type in the <code>DynaClass.


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

Restricted DynaClass

MutableDynaClass</code> have a facility to <em>restrict</em> the <code>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:

  • Field Details

  • Constructor Details

    • LazyDynaBean

      public LazyDynaBean()
      Constructs a new LazyDynaBean</code> with a <code>LazyDynaClass instance.

    • LazyDynaBean

      public LazyDynaBean(DynaClass dynaClass)
      Constructs a new DynaBean associated with the specified DynaClass</code> instance - if its not a <code>MutableDynaClass then a new LazyDynaClass is created and the properties copied.
      Parameters:
      dynaClass - The DynaClass we are associated with

    • LazyDynaBean

      public LazyDynaBean(String name)
      Constructs a new LazyDynaBean</code> with a <code>LazyDynaClass instance.
      Parameters:
      name - Name of this DynaBean class

  • Method Details

    • 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

    • 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

    • 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

    • createNumberProperty

      protected Object createNumberProperty(String name, Class<?> type)
      Create a new Instance of a 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

    • 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

    • 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

    • defaultIndexedProperty

      protected Object defaultIndexedProperty(String name)

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

      This method should be overridden 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<String,Object> defaultMappedProperty(String name)

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

      This method can be overridden 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)

    • 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()
      Gets the DynaClass instance that describes the set of properties available for this DynaBean.
      Specified by:
      getDynaClass in interface DynaBean
      Returns:
      The associated DynaClass

    • getMap

      public Map<String,Object> getMap()

      Gets 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.<strong>map</strong>.fooProperty}
      Returns:
      a Map representation of this DynaBean

    • 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)

    • 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

    • 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

    • newMap

      protected Map<String,Object> newMap()

      Creates a new instance of the Map.

      Returns:
      a new Map instance

    • 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, int index, Object value)
      Sets 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, Object value)
      Sets 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, String key, Object value)
      Sets 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

    • 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