Class AbstractInputCheckedMapDecorator

java.lang.Object
org.apache.commons.collections.map.AbstractMapDecorator
org.apache.commons.collections.map.AbstractInputCheckedMapDecorator
All Implemented Interfaces:
Map
Direct Known Subclasses:
PredicatedMap, TransformedMap

abstract class AbstractInputCheckedMapDecorator extends AbstractMapDecorator
An abstract base class that simplifies the task of creating map decorators.

The Map API is very difficult to decorate correctly, and involves implementing lots of different classes. This class exists to provide a simpler API.

Special hook methods are provided that are called when objects are added to the map. By overriding these methods, the input can be validated or manipulated. In addition to the main map methods, the entrySet is also affected, which is the hardest part of writing map implementations.

This class is package-scoped, and may be withdrawn or replaced in future versions of Commons Collections.

Since:
Commons Collections 3.1
Version:
$Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
  • Constructor Details

    • AbstractInputCheckedMapDecorator

      protected AbstractInputCheckedMapDecorator()
      Constructor only used in deserialization, do not use otherwise.
    • AbstractInputCheckedMapDecorator

      protected AbstractInputCheckedMapDecorator(Map map)
      Constructor that wraps (not copies).
      Parameters:
      map - the map to decorate, must not be null
      Throws:
      IllegalArgumentException - if map is null
  • Method Details

    • checkSetValue

      protected abstract Object checkSetValue(Object value)
      Hook method called when a value is being set using setValue.

      An implementation may validate the value and throw an exception or it may transform the value into another object.

      This implementation returns the input value.

      Parameters:
      value - the value to check
      Throws:
      UnsupportedOperationException - if the map may not be changed by setValue
      IllegalArgumentException - if the specified value is invalid
      ClassCastException - if the class of the specified value is invalid
      NullPointerException - if the specified value is null and nulls are invalid
    • isSetValueChecking

      protected boolean isSetValueChecking()
      Hook method called to determine if checkSetValue has any effect.

      An implementation should return false if the checkSetValue method has no effect as this optimises the implementation.

      This implementation returns true.

      Returns:
      true always
    • entrySet

      public Set entrySet()
      Specified by:
      entrySet in interface Map
      Overrides:
      entrySet in class AbstractMapDecorator