org.apache.commons.beanutils

## Class LazyDynaMap

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

- All Implemented Interfaces:
    Serializable, DynaBean, DynaClass, MutableDynaClass

      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:

  - Properties don't need to be pre-defined in a `DynaClass`
  - Indexed properties (`Lists` or `Arrays`) are automatically instantiated and grown so that they are large enough to cater for the index being set.
  - Mapped properties are automatically instantiated.

  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.

  Version:
    $Id$
  See Also:
    Serialized Form

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `protected String` | `name` The name of this DynaClass (analogous to the `getName()` method of `java.lang.Class`).
    `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.

    - ### Fields inherited from class org.apache.commons.beanutils.LazyDynaBean

      `BigDecimal_ZERO, BigInteger_ZERO, Byte_ZERO, Character_SPACE, Double_ZERO, dynaClass, Float_ZERO, Integer_ZERO, Long_ZERO, Short_ZERO, values`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `LazyDynaMap()` Default Constructor.
    `LazyDynaMap(DynaClass dynaClass)` Construct a new `LazyDynaMap` based on an exisiting DynaClass
    `LazyDynaMap(DynaProperty[] properties)` Construct a new `LazyDynaMap` with the specified properties.
    `LazyDynaMap(Map<String,Object> values)` Construct a new `LazyDynaMap` with the specified `Map`.
    `LazyDynaMap(String name)` Construct a new `LazyDynaMap` with the specified name.
    `LazyDynaMap(String name, DynaProperty[] properties)` Construct a new `LazyDynaMap` with the specified name and properties.
    `LazyDynaMap(String name, Map<String,Object> values)` Construct a new `LazyDynaMap` with the specified name and `Map`.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `protected void` | `add(DynaProperty property)` Add a new dynamic property.
    `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.
    `DynaProperty[]` | `getDynaProperties()` Return an array of `ProperyDescriptors` for the properties currently defined in this DynaClass.
    `DynaProperty` | `getDynaProperty(String name)` Return a property descriptor for the specified property.
    `Map<String,Object>` | `getMap()` Return the underlying Map backing this `DynaBean`
    `String` | `getName()` Return the name of this DynaClass (analogous to the `getName()` method of `java.lang.Class`)
    `protected 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.
    `DynaBean` | `newInstance()` Instantiate and return a new DynaBean instance, associated with this DynaClass.
    `void` | `remove(String name)` Remove the specified dynamic property, and any associated data type, readability, and writeability, from this dynamic class.
    `void` | `set(String name, Object value)` Set the value of a simple property with the specified name.
    `void` | `setMap(Map<String,Object> values)` Set the Map backing this `DynaBean`
    `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.

    - ### Methods inherited from class org.apache.commons.beanutils.LazyDynaBean

      `contains, createDynaBeanProperty, createIndexedProperty, createMappedProperty, createNumberProperty, createOtherProperty, createPrimitiveProperty, createProperty, defaultIndexedProperty, defaultMappedProperty, get, get, get, getDynaClass, growIndexedProperty, isAssignable, newMap, remove, set, set, size`

    - ### Methods inherited from class java.lang.Object

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

- - ### 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<String,Object> values)

      Construct a new `LazyDynaMap` with the specified `Map`.
      Parameters:
        `values` - The Map backing this `LazyDynaMap`

    - #### LazyDynaMap

          public LazyDynaMap(String name,
                             Map<String,Object> 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

    - #### setMap

          public void setMap(Map<String,Object> values)

      Set the Map backing this `DynaBean`
      Parameters:
        `values` - The new Map of values

    - #### getMap

          public Map<String,Object> getMap()

      Return the underlying Map backing this `DynaBean`
      Overrides:
        `getMap` in class `LazyDynaBean`
      Returns:
        the underlying Map
      Since:
        1.8.0

    - #### 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`
      Overrides:
        `set` in class `LazyDynaBean`
      Parameters:
        `name` - Name of the property whose value is to be set
        `value` - Value to which this property is to be set

    - #### getName

          public String getName()

      Return the name of this DynaClass (analogous to the `getName()` method of `java.lang.Class`)
      Specified by:
        `getName` in interface `DynaClass`
      Returns:
        the name of the 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.

      Specified by:
        `getDynaProperty` in interface `DynaClass`
      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

    - #### 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?

      Specified by:
        `getDynaProperties` in interface `DynaClass`
      Returns:
        the set of properties for this DynaClass

    - #### newInstance

          public DynaBean newInstance()

      Instantiate and return a new DynaBean instance, associated with this DynaClass.
      Specified by:
        `newInstance` in interface `DynaClass`
      Returns:
        A new `DynaBean` instance

    - #### 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.

      Specified by:
        `isRestricted` in interface `MutableDynaClass`
      Returns:
        `true` if this Mutable `DynaClass` is restricted, otherwise `false`

    - #### 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.

      Specified by:
        `setRestricted` in interface `MutableDynaClass`
      Parameters:
        `restricted` - The new restricted state

    - #### add

          public void add(String name)

      Add a new dynamic property with no restrictions on data type, readability, or writeability.
      Specified by:
        `add` in interface `MutableDynaClass`
      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.
      Specified by:
        `add` in interface `MutableDynaClass`
      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.

      Specified by:
        `add` in interface `MutableDynaClass`
      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

    - #### 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.
      Specified by:
        `remove` in interface `MutableDynaClass`
      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

    - #### 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.

    - #### 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.

    - #### 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).

      Overrides:
        `isDynaProperty` in class `LazyDynaBean`
      Parameters:
        `name` - Name of the dynamic property
      Returns:
        `true` if the property exists, otherwise `false`
      Throws:
        `IllegalArgumentException` - if no property name is specified

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