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org.eclipse.core.databinding
Class UpdateListStrategy
java.lang.Object
org.eclipse.core.databinding.UpdateListStrategy
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public class UpdateListStrategy
- extends
Object
Customizes a
Binding between two
observable lists. The following behaviors can be customized via the strategy:
- Conversion
- Automatic processing
Conversion:
When elements are added they can be
converted to the
destination element type.
Automatic processing:
The processing to perform when the source observable changes. This behavior
is configured via policies provided on construction of the strategy (e.g.
POLICY_NEVER,
POLICY_ON_REQUEST,
POLICY_UPDATE).
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Since:
- 1.0
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See Also:
-
DataBindingContext.bindList(IObservableList, IObservableList, UpdateListStrategy, UpdateListStrategy),
IConverter
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Field Summary
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protected
IConverter
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converter
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static int
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POLICY_NEVER
Policy constant denoting that the source observable's state should not be
tracked and that the destination observable's state should never be
updated. |
static int
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POLICY_ON_REQUEST
Policy constant denoting that the source observable's state should not be
tracked, but that conversion and updating the destination observable's
state should be performed when explicitly requested. |
static int
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POLICY_UPDATE
Policy constant denoting that the source observable's state should be
tracked, and that conversion and updating the destination observable's
state should be performed automatically on every change of the source
observable state. |
protected boolean
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provideDefaults
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Constructor Summary
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UpdateListStrategy
()
Creates a new update list strategy for automatically updating the
destination observable list whenever the source observable list changes. |
UpdateListStrategy
(boolean provideDefaults,
int updatePolicy)
Creates a new update list strategy with a configurable update policy. |
UpdateListStrategy
(int updatePolicy)
Creates a new update list strategy with a configurable update policy. |
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Method Summary
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protected void
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checkAssignable
(
Object toType,
Object fromType,
String errorString)
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Object
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convert
(
Object element)
When an element is added to the destination converts the element from the
source element type to the destination element type. |
protected
IConverter
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createConverter
(
Object fromType,
Object toType)
Tries to create a converter that can convert from values of type
fromType. |
protected
IStatus
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doAdd
(
IObservableList observableList,
Object element,
int index)
Adds the given element at the given index to the given observable list. |
protected
IStatus
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doMove
(
IObservableList observableList,
int oldIndex,
int newIndex)
Moves the element in the observable list located at the given old index
to the given new index. |
protected
IStatus
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doRemove
(
IObservableList observableList,
int index)
Removes the element at the given index from the given observable list. |
protected
IStatus
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doReplace
(
IObservableList observableList,
int index,
Object element)
Replaces the element in the observable list located at the given index to
with the given element. |
protected void
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fillDefaults
(
IObservableList source,
IObservableList destination)
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int
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getUpdatePolicy
()
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protected
Boolean
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isAssignableFromTo
(
Object fromType,
Object toType)
Returns
Boolean.TRUE
if the from type is assignable to the to
type, or
Boolean.FALSE
if it not, or null if
unknown. |
UpdateListStrategy
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setConverter
(
IConverter converter)
Sets the converter to be invoked when converting added elements from the
source element type to the destination element type. |
protected boolean
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useMoveAndReplace
()
Returns whether ListBinding should call
doMove(IObservableList, int, int) and
doReplace(IObservableList, int, Object) instead of paired calls
to
doRemove(IObservableList, int) and
doAdd(IObservableList, Object, int). |
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Methods inherited from class java.lang.
Object
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clone,
equals,
finalize,
getClass,
hashCode,
notify,
notifyAll,
toString,
wait,
wait,
wait
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POLICY_NEVER
public static int POLICY_NEVER
- Policy constant denoting that the source observable's state should not be
tracked and that the destination observable's state should never be
updated.
POLICY_ON_REQUEST
public static int POLICY_ON_REQUEST
- Policy constant denoting that the source observable's state should not be
tracked, but that conversion and updating the destination observable's
state should be performed when explicitly requested.
POLICY_UPDATE
public static int POLICY_UPDATE
- Policy constant denoting that the source observable's state should be
tracked, and that conversion and updating the destination observable's
state should be performed automatically on every change of the source
observable state.
converter
protected
IConverter converter
provideDefaults
protected boolean provideDefaults
UpdateListStrategy
public UpdateListStrategy()
- Creates a new update list strategy for automatically updating the
destination observable list whenever the source observable list changes.
A default converter will be provided. The defaults can be changed by
calling one of the setter methods.
UpdateListStrategy
public UpdateListStrategy(int updatePolicy)
- Creates a new update list strategy with a configurable update policy. A
default converter will be provided. The defaults can be changed by
calling one of the setter methods.
-
Parameters:
-
updatePolicy - one of
POLICY_NEVER,
POLICY_ON_REQUEST, or
POLICY_UPDATE
UpdateListStrategy
public UpdateListStrategy(boolean provideDefaults,
int updatePolicy)
- Creates a new update list strategy with a configurable update policy. A
default converter will be provided if
provideDefaults is
true. The defaults can be changed by calling one of the
setter methods.
-
Parameters:
-
provideDefaults - if true, default validators and a default
converter will be provided based on the observable list's
type. -
updatePolicy - one of
POLICY_NEVER,
POLICY_ON_REQUEST, or
POLICY_UPDATE
convert
public
Object convert(
Object element)
- When an element is added to the destination converts the element from the
source element type to the destination element type.
Default implementation will use the
converter if one exists. If no converter exists no conversion occurs.
-
-
Parameters:
-
element -
-
Returns:
- the converted element
fillDefaults
protected void fillDefaults(
IObservableList source,
IObservableList destination)
-
-
Parameters:
-
source - -
destination -
getUpdatePolicy
public int getUpdatePolicy()
-
-
Returns:
- the update policy
setConverter
public
UpdateListStrategy setConverter(
IConverter converter)
- Sets the converter to be invoked when converting added elements from the
source element type to the destination element type.
-
-
Parameters:
-
converter -
-
Returns:
- the receiver, to enable method call chaining
doAdd
protected
IStatus doAdd(
IObservableList observableList,
Object element,
int index)
- Adds the given element at the given index to the given observable list.
Clients may extend but must call the super implementation.
-
-
Parameters:
-
observableList - -
element - -
index -
-
Returns:
- a status
doRemove
protected
IStatus doRemove(
IObservableList observableList,
int index)
- Removes the element at the given index from the given observable list.
Clients may extend but must call the super implementation.
-
-
Parameters:
-
observableList - -
index -
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Returns:
- a status
useMoveAndReplace
protected boolean useMoveAndReplace()
- Returns whether ListBinding should call
doMove(IObservableList, int, int) and
doReplace(IObservableList, int, Object) instead of paired calls
to
doRemove(IObservableList, int) and
doAdd(IObservableList, Object, int). The default implementation
returns true for this class and false for subclasses.
This method is provided for the benefit of subclasses which extend the
doAdd(IObservableList, Object, int) and
doRemove(IObservableList, int) methods. The
doMove(IObservableList, int, int) and
doReplace(IObservableList, int, Object) methods were added in
version 1.2 so that logically related remove() and add() operations could
be combined into a single method call. However to ensure that custom
behavior is not lost in existing code,
ListBinding is advised by
this method whether these new methods may be used.
To enable use of these methods in subclasses, override this method to
return true.
-
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Returns:
- whether ListBinding should call doMove() and doReplace() instead
of paired calls of doRemove() and doAdd()
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Since:
- 1.2
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Restriction:
- This method is not intended to be referenced by clients.
doMove
protected
IStatus doMove(
IObservableList observableList,
int oldIndex,
int newIndex)
- Moves the element in the observable list located at the given old index
to the given new index.
-
-
Parameters:
-
observableList - -
oldIndex - -
newIndex -
-
Returns:
- a status
-
Since:
- 1.2
doReplace
protected
IStatus doReplace(
IObservableList observableList,
int index,
Object element)
- Replaces the element in the observable list located at the given index to
with the given element.
-
-
Parameters:
-
observableList - -
index - -
element -
-
Returns:
- a status
-
Since:
- 1.2
checkAssignable
protected final void checkAssignable(
Object toType,
Object fromType,
String errorString)
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createConverter
protected
IConverter createConverter(
Object fromType,
Object toType)
- Tries to create a converter that can convert from values of type
fromType. Returns
null if no converter could be created.
Either toType or modelDescription can be null, but not
both.
-
-
Parameters:
-
fromType - -
toType -
-
Returns:
- an IConverter, or
null if unsuccessful
isAssignableFromTo
protected
Boolean isAssignableFromTo(
Object fromType,
Object toType)
- Returns
Boolean.TRUE
if the from type is assignable to the to
type, or
Boolean.FALSE
if it not, or null if
unknown.
-
-
Parameters:
-
fromType - -
toType -
-
Returns:
- whether fromType is assignable to toType, or
null
if unknown
Guidelines for using Eclipse APIs.
Copyright (c) Eclipse contributors and others 2000, 2008. All rights reserved.
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