com.google.gwt.view.client

## Class DefaultSelectionModel<T>

- java.lang.Object
- - com.google.gwt.view.client.SelectionModel.AbstractSelectionModel<T>
  - - com.google.gwt.view.client.DefaultSelectionModel<T>

- Type Parameters:
    `T` - the data type of records in the list
  All Implemented Interfaces:
    HasHandlers, ProvidesKey<T>, SelectionChangeEvent.HasSelectionChangedHandlers, SelectionModel<T>

      public abstract class DefaultSelectionModel<T>
      extends SelectionModel.AbstractSelectionModel<T>

  A convenience `SelectionModel` that allows items to be selected according to a subclass-defined rule, plus a list of positive or negative exceptions.

- - ### Nested Class Summary

    - ### Nested classes/interfaces inherited from interface com.google.gwt.view.client.SelectionModel

      `SelectionModel.AbstractSelectionModel<T>`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `DefaultSelectionModel()` Constructs a DefaultSelectionModel without a key provider.
    `DefaultSelectionModel(ProvidesKey<T> keyProvider)` Constructs a DefaultSelectionModel with the given key provider.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `clearExceptions()` Removes all exceptions.
    `protected void` | `fireSelectionChangeEvent()` Fire a `SelectionChangeEvent`.
    `protected java.util.Map<java.lang.Object,java.lang.Boolean>` | `getExceptions(java.util.Map<java.lang.Object,java.lang.Boolean> output)` Copies the exceptions map into a user-supplied map.
    `abstract boolean` | `isDefaultSelected(T item)` Returns true if the given item should be selected by default.
    `boolean` | `isSelected(T item)` If the given item is marked as an exception, return the exception value.
    `void` | `setSelected(T item, boolean selected)` Sets an item's selection state.

    - ### Methods inherited from class com.google.gwt.view.client.SelectionModel.AbstractSelectionModel

      `addSelectionChangeHandler, fireEvent, getKey, getKeyProvider, isEventCancelled, isEventScheduled, scheduleSelectionChangeEvent, setEventCancelled, setEventScheduled`

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

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

- - ### Constructor Detail

    - #### DefaultSelectionModel

          public DefaultSelectionModel()

      Constructs a DefaultSelectionModel without a key provider.

    - #### DefaultSelectionModel

          public DefaultSelectionModel(ProvidesKey<T> keyProvider)

      Constructs a DefaultSelectionModel with the given key provider.
      Parameters:
        `keyProvider` - an instance of ProvidesKey, or null if the item should act as its own key

  - ### Method Detail

    - #### clearExceptions

          public void clearExceptions()

      Removes all exceptions.

    - #### isDefaultSelected

          public abstract boolean isDefaultSelected(T item)

      Returns true if the given item should be selected by default. Subclasses implement this method in order to define the default selection behavior.
      Parameters:
        `item` - an object of this `SelectionModel`'s type
      Returns:
        true if the item should be selected by default

    - #### isSelected

          public boolean isSelected(T item)

      If the given item is marked as an exception, return the exception value. Otherwise, return the value of isDefaultSelected for the given item.
      Parameters:
        `item` - the object
      Returns:
        true if selected, false if not

    - #### setSelected

          public void setSelected(T item,
                         boolean selected)

      Sets an item's selection state. If the item is currently marked as an exception, and the new selected state differs from the previous selected state, the object is removed from the list of exceptions. Otherwise, the object is added to the list of exceptions with the given selected state.
      Parameters:
        `item` - the object to select or deselect
        `selected` - true to select, false to deselect

    - #### fireSelectionChangeEvent

          protected void fireSelectionChangeEvent()

      Description copied from class: `SelectionModel.AbstractSelectionModel`
      Fire a `SelectionChangeEvent`. Multiple firings may be coalesced.
      Overrides:
        `fireSelectionChangeEvent` in class `SelectionModel.AbstractSelectionModel<T>`

    - #### getExceptions

          protected java.util.Map<java.lang.Object,java.lang.Boolean> getExceptions(java.util.Map<java.lang.Object,java.lang.Boolean> output)

      Copies the exceptions map into a user-supplied map.
      Parameters:
        `output` - the user supplied map
      Returns:
        the user supplied map