org.eclipse.core.databinding
Class UpdateValueStrategy
java.lang.Object
org.eclipse.core.databinding.UpdateValueStrategy
-
public class UpdateValueStrategy
- extends
Object
Customizes a
Binding between two
observable values. The following behaviors can be customized via the strategy:
- Validation
- Conversion
- Automatic processing
The update phases are:
- Validate after get -
validateAfterGet(Object)
- Conversion -
convert(Object)
- Validate after conversion -
validateAfterConvert(Object)
- Validate before set -
validateBeforeSet(Object)
- Value set -
doSet(IObservableValue, Object)
Validation:
Validators validate the value at multiple phases in the
update process. Statuses returned from validators are aggregated into a
MultiStatus until a status of ERROR or
CANCEL is encountered. Either of these statuses will abort the
update process. These statuses are available as the
binding validation status.
Conversion:
A
converter will convert the value from the type of the
source observable into the type of the destination. The strategy has the
ability to default converters for common scenarios.
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_CONVERT,
POLICY_ON_REQUEST,
POLICY_UPDATE).
-
Since:
- 1.0
-
See Also:
-
DataBindingContext.bindValue(IObservableValue, IObservableValue, UpdateValueStrategy, UpdateValueStrategy),
ValidationStatusProvider.getValidationStatus(),
IValidator,
IConverter
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Field Summary
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protected
IValidator
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afterConvertValidator
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protected
IValidator
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afterGetValidator
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protected
IValidator
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beforeSetValidator
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protected
IConverter
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converter
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static int
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POLICY_CONVERT
Policy constant denoting that the source observable's state should be
tracked, including validating changes except for
validateBeforeSet(Object), but that the destination observable's
value should only be updated on request. |
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 value 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 validation, conversion and updating the destination
observable's value should be performed when explicitly requested. |
static int
|
POLICY_UPDATE
Policy constant denoting that the source observable's state should be
tracked, and that validation, conversion and updating the destination
observable's value should be performed automaticlly on every change of
the source observable value. |
protected boolean
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provideDefaults
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Constructor Summary
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UpdateValueStrategy
()
Creates a new update value strategy for automatically updating the
destination observable value whenever the source observable value
changes. |
UpdateValueStrategy
(boolean provideDefaults,
int updatePolicy)
Creates a new update value strategy with a configurable update policy. |
UpdateValueStrategy
(int updatePolicy)
Creates a new update value strategy with a configurable update policy. |
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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 value 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 validation, conversion and updating the destination
observable's value should be performed when explicitly requested.
POLICY_CONVERT
public static int POLICY_CONVERT
- Policy constant denoting that the source observable's state should be
tracked, including validating changes except for
validateBeforeSet(Object), but that the destination observable's
value should only be updated on request.
POLICY_UPDATE
public static int POLICY_UPDATE
- Policy constant denoting that the source observable's state should be
tracked, and that validation, conversion and updating the destination
observable's value should be performed automaticlly on every change of
the source observable value.
afterGetValidator
protected
IValidator afterGetValidator
afterConvertValidator
protected
IValidator afterConvertValidator
beforeSetValidator
protected
IValidator beforeSetValidator
converter
protected
IConverter converter
provideDefaults
protected boolean provideDefaults
UpdateValueStrategy
public UpdateValueStrategy()
- Creates a new update value strategy for automatically updating the
destination observable value whenever the source observable value
changes. Default validators and a default converter will be provided. The
defaults can be changed by calling one of the setter methods.
UpdateValueStrategy
public UpdateValueStrategy(int updatePolicy)
- Creates a new update value strategy with a configurable update policy.
Default validators and 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,
POLICY_CONVERT, or
POLICY_UPDATE
UpdateValueStrategy
public UpdateValueStrategy(boolean provideDefaults,
int updatePolicy)
- Creates a new update value strategy with a configurable update policy.
Default validators and 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 value's
type. -
updatePolicy - one of
POLICY_NEVER,
POLICY_ON_REQUEST,
POLICY_CONVERT, or
POLICY_UPDATE
convert
public
Object convert(
Object value)
- Converts the value from the source type to the destination type.
Default implementation will use the
converter if one exists. If no converter exists no conversion occurs.
-
-
Parameters:
-
value -
-
Returns:
- the converted value
createValidator
protected
IValidator createValidator(
Object fromType,
Object toType)
- Tries to create a validator that can validate values of type fromType.
Returns
null if no validator could be created. Either toType
or modelDescription can be null, but not both.
-
-
Parameters:
-
fromType - -
toType -
-
Returns:
- an IValidator, or
null if unsuccessful
fillDefaults
protected void fillDefaults(
IObservableValue source,
IObservableValue destination)
- Fills out default values based upon the provided
source and
destination. If the strategy is to default values it will
attempt to default a converter. If the converter can be defaulted an
attempt is made to default the
after get validator. If a validator cannot be defaulted it will be
null.
-
-
Parameters:
-
source - -
destination -
getUpdatePolicy
public int getUpdatePolicy()
-
-
Returns:
- the update policy
setAfterConvertValidator
public
UpdateValueStrategy setAfterConvertValidator(
IValidator validator)
- Sets the validator to be invoked after the source value is converted to
the type of the destination observable.
-
-
Parameters:
-
validator -
-
Returns:
- the receiver, to enable method call chaining
setAfterGetValidator
public
UpdateValueStrategy setAfterGetValidator(
IValidator validator)
- Sets the validator to be invoked after the source value is retrieved at
the beginning of the synchronization process.
-
-
Parameters:
-
validator -
-
Returns:
- the receiver, to enable method call chaining
setBeforeSetValidator
public
UpdateValueStrategy setBeforeSetValidator(
IValidator validator)
- Sets the validator to be invoked before the value is to be set on the
destination at the end of the synchronization process.
-
-
Parameters:
-
validator -
-
Returns:
- the receiver, to enable method call chaining
setConverter
public
UpdateValueStrategy setConverter(
IConverter converter)
- Sets the converter to be invoked when converting from the source type to
the destination type.
-
-
Parameters:
-
converter -
-
Returns:
- the receiver, to enable method call chaining
validateAfterConvert
public
IStatus validateAfterConvert(
Object value)
- Validates the value after it is converted.
Default implementation will use the
validator if one exists. If
one does not exist no validation will occur.
-
-
Parameters:
-
value -
-
Returns:
- an ok status
validateAfterGet
public
IStatus validateAfterGet(
Object value)
- Validates the value after it is retrieved from the source.
Default implementation will use the
validator if one exists. If one
does not exist no validation will occur.
-
-
Parameters:
-
value -
-
Returns:
- an ok status
validateBeforeSet
public
IStatus validateBeforeSet(
Object value)
- Validates the value before it is set on the destination.
Default implementation will use the
validator if one exists. If
one does not exist no validation will occur.
-
-
Parameters:
-
value -
-
Returns:
- an ok status
doSet
protected
IStatus doSet(
IObservableValue observableValue,
Object value)
- Sets the current value of the given observable to the given value.
Clients may extend but must call the super implementation.
-
-
Parameters:
-
observableValue - -
value -
-
Returns:
- status
checkAssignable
protected final void checkAssignable(
Object toType,
Object fromType,
String errorString)
-
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
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