Interface IPreferenceStore
- All Known Subinterfaces:
IPersistentPreferenceStore
- All Known Implementing Classes:
ChainedPreferenceStore
,OverlayPreferenceStore
,PreferenceStore
,ScopedPreferenceStore
IPreferenceStore
interface represents a table mapping
named preferences to values. If there is no value for a given name,
then that preferences's default value is returned; and if there is no
default value for that preference, then a default-default value is returned.
The default-default values for the primitive types are as follows:
boolean
=false
double
=0.0
float
=0.0f
int
=0
long
=0
String
=""
(the empty string)
Thus a preference store maintains two values for each of a set of names: a current value and a default value. The typical usage is to establish the defaults for all known preferences and then restore previously stored values for preferences whose values were different from their defaults. After the current values of the preferences have been modified, it is a simple matter to write out only those preferences whose values are different from their defaults. This two-tiered approach to saving and restoring preference setting minimized the number of preferences that need to be persisted; indeed, the normal starting state does not require storing any preferences at all.
A property change event is reported whenever a preferences current
value actually changes (whether through setValue
,
setToDefault
, or other unspecified means). Note, however,
that manipulating default values (with setDefault
)
does not cause such events to be reported.
Clients who need a preference store may implement this interface or
instantiate the standard implementation PreferenceStore
.
- See Also:
-
Field Summary
Modifier and TypeFieldDescriptionstatic final boolean
The default-default value for boolean preferences (false
).static final double
The default-default value for double preferences (0.0
).static final String
The string representation used forfalse
("false"
).static final float
The default-default value for float preferences (0.0f
).static final int
The default-default value for int preferences (0
).static final long
The default-default value for long preferences (0L
).static final String
The default-default value for String preferences (""
).static final String
The string representation used fortrue
("true"
). -
Method Summary
Modifier and TypeMethodDescriptionvoid
Adds a property change listener to this preference store.boolean
Returns whether the named preference is known to this preference store.void
firePropertyChangeEvent
(String name, Object oldValue, Object newValue) Fires a property change event corresponding to a change to the current value of the preference with the given name.boolean
getBoolean
(String name) Returns the current value of the boolean-valued preference with the given name.boolean
getDefaultBoolean
(String name) Returns the default value for the boolean-valued preference with the given name.double
getDefaultDouble
(String name) Returns the default value for the double-valued preference with the given name.float
getDefaultFloat
(String name) Returns the default value for the float-valued preference with the given name.int
getDefaultInt
(String name) Returns the default value for the integer-valued preference with the given name.long
getDefaultLong
(String name) Returns the default value for the long-valued preference with the given name.getDefaultString
(String name) Returns the default value for the string-valued preference with the given name.double
Returns the current value of the double-valued preference with the given name.float
Returns the current value of the float-valued preference with the given name.int
Returns the current value of the integer-valued preference with the given name.long
Returns the current value of the long-valued preference with the given name.Returns the current value of the string-valued preference with the given name.boolean
Returns whether the current value of the preference with the given name has the default value.boolean
Returns whether the current values in this property store require saving.void
Sets the current value of the preference with the given name to the given string value without sending a property change.void
Removes the given listener from this preference store.void
setDefault
(String name, boolean value) Sets the default value for the boolean-valued preference with the given name.void
setDefault
(String name, double value) Sets the default value for the double-valued preference with the given name.void
setDefault
(String name, float value) Sets the default value for the float-valued preference with the given name.void
setDefault
(String name, int value) Sets the default value for the integer-valued preference with the given name.void
setDefault
(String name, long value) Sets the default value for the long-valued preference with the given name.void
setDefault
(String name, String defaultObject) Sets the default value for the string-valued preference with the given name.void
setToDefault
(String name) Sets the current value of the preference with the given name back to its default value.void
Sets the current value of the boolean-valued preference with the given name.void
Sets the current value of the double-valued preference with the given name.void
Sets the current value of the float-valued preference with the given name.void
Sets the current value of the integer-valued preference with the given name.void
Sets the current value of the long-valued preference with the given name.void
Sets the current value of the string-valued preference with the given name.
-
Field Details
-
BOOLEAN_DEFAULT_DEFAULT
static final boolean BOOLEAN_DEFAULT_DEFAULTThe default-default value for boolean preferences (false
).- See Also:
-
DOUBLE_DEFAULT_DEFAULT
static final double DOUBLE_DEFAULT_DEFAULTThe default-default value for double preferences (0.0
).- See Also:
-
FLOAT_DEFAULT_DEFAULT
static final float FLOAT_DEFAULT_DEFAULTThe default-default value for float preferences (0.0f
).- See Also:
-
INT_DEFAULT_DEFAULT
static final int INT_DEFAULT_DEFAULTThe default-default value for int preferences (0
).- See Also:
-
LONG_DEFAULT_DEFAULT
static final long LONG_DEFAULT_DEFAULTThe default-default value for long preferences (0L
).- See Also:
-
STRING_DEFAULT_DEFAULT
The default-default value for String preferences (""
).- See Also:
-
TRUE
The string representation used fortrue
("true"
).- See Also:
-
FALSE
The string representation used forfalse
("false"
).- See Also:
-
-
Method Details
-
addPropertyChangeListener
Adds a property change listener to this preference store.
Note The types of the oldValue and newValue of the generated PropertyChangeEvent are determined by whether or not the typed API in IPreferenceStore was called. If values are changed via setValue(name,type) the values in the PropertyChangedEvent will be of that type. If they are set using a non typed API (i.e. #setToDefault or using the OSGI Preferences) the values will be unconverted Strings.
A listener will be called in the same Thread that it is invoked in. Any Thread dependant listeners (such as those who update an SWT widget) will need to update in the correct Thread. In the case of an SWT update you can update using Display#syncExec(Runnable) or Display#asyncExec(Runnable).
Likewise any application that updates an IPreferenceStore from a Thread other than the UI Thread should be aware of any listeners that require an update in the UI Thread.
- Parameters:
listener
- a property change listener- See Also:
-
contains
Returns whether the named preference is known to this preference store.- Parameters:
name
- the name of the preference- Returns:
true
if either a current value or a default value is known for the named preference, andfalse
otherwise
-
firePropertyChangeEvent
Fires a property change event corresponding to a change to the current value of the preference with the given name.This method is provided on this interface to simplify the implementation of decorators. There is normally no need to call this method since
setValue
andsetToDefault
report such events in due course. Implementations should funnel all preference changes through this method.- Parameters:
name
- the name of the preference, to be used as the property in the event objectoldValue
- the old valuenewValue
- the new value
-
getBoolean
Returns the current value of the boolean-valued preference with the given name. Returns the default-default value (false
) if there is no preference with the given name, or if the current value cannot be treated as a boolean.- Parameters:
name
- the name of the preference- Returns:
- the boolean-valued preference
-
getDefaultBoolean
Returns the default value for the boolean-valued preference with the given name. Returns the default-default value (false
) if there is no default preference with the given name, or if the default value cannot be treated as a boolean.- Parameters:
name
- the name of the preference- Returns:
- the default value of the named preference
-
getDefaultDouble
Returns the default value for the double-valued preference with the given name. Returns the default-default value (0.0
) if there is no default preference with the given name, or if the default value cannot be treated as a double.- Parameters:
name
- the name of the preference- Returns:
- the default value of the named preference
-
getDefaultFloat
Returns the default value for the float-valued preference with the given name. Returns the default-default value (0.0f
) if there is no default preference with the given name, or if the default value cannot be treated as a float.- Parameters:
name
- the name of the preference- Returns:
- the default value of the named preference
-
getDefaultInt
Returns the default value for the integer-valued preference with the given name. Returns the default-default value (0
) if there is no default preference with the given name, or if the default value cannot be treated as an integer.- Parameters:
name
- the name of the preference- Returns:
- the default value of the named preference
-
getDefaultLong
Returns the default value for the long-valued preference with the given name. Returns the default-default value (0L
) if there is no default preference with the given name, or if the default value cannot be treated as a long.- Parameters:
name
- the name of the preference- Returns:
- the default value of the named preference
-
getDefaultString
Returns the default value for the string-valued preference with the given name. Returns the default-default value (the empty string""
) is no default preference with the given name, or if the default value cannot be treated as a string.- Parameters:
name
- the name of the preference- Returns:
- the default value of the named preference
-
getDouble
Returns the current value of the double-valued preference with the given name. Returns the default-default value (0.0
) if there is no preference with the given name, or if the current value cannot be treated as a double.- Parameters:
name
- the name of the preference- Returns:
- the double-valued preference
-
getFloat
Returns the current value of the float-valued preference with the given name. Returns the default-default value (0.0f
) if there is no preference with the given name, or if the current value cannot be treated as a float.- Parameters:
name
- the name of the preference- Returns:
- the float-valued preference
-
getInt
Returns the current value of the integer-valued preference with the given name. Returns the default-default value (0
) if there is no preference with the given name, or if the current value cannot be treated as an integer.- Parameters:
name
- the name of the preference- Returns:
- the int-valued preference
-
getLong
Returns the current value of the long-valued preference with the given name. Returns the default-default value (0L
) if there is no preference with the given name, or if the current value cannot be treated as a long.- Parameters:
name
- the name of the preference- Returns:
- the long-valued preference
-
getString
Returns the current value of the string-valued preference with the given name. Returns the default-default value (the empty string""
) if there is no preference with the given name, or if the current value cannot be treated as a string.- Parameters:
name
- the name of the preference- Returns:
- the string-valued preference
-
isDefault
Returns whether the current value of the preference with the given name has the default value.- Parameters:
name
- the name of the preference- Returns:
true
if the preference has a known default value and its current value is the same, andfalse
otherwise (including the case where the preference is unknown to this store)
-
needsSaving
boolean needsSaving()Returns whether the current values in this property store require saving.- Returns:
true
if at least one of values of the preferences known to this store has changed and requires saving, andfalse
otherwise.
-
putValue
Sets the current value of the preference with the given name to the given string value without sending a property change.This method does not fire a property change event and should only be used for setting internal preferences that are not meant to be processed by listeners. Normal clients should instead call #setValue.
- Parameters:
name
- the name of the preferencevalue
- the new current value of the preference
-
removePropertyChangeListener
Removes the given listener from this preference store. Has no effect if the listener is not registered.- Parameters:
listener
- a property change listener, must not benull
-
setDefault
Sets the default value for the double-valued preference with the given name.Note that the current value of the preference is affected if the preference's current value was its old default value, in which case it changes to the new default value. If the preference's current is different from its old default value, its current value is unaffected. No property change events are reported by changing default values.
- Parameters:
name
- the name of the preferencevalue
- the new default value for the preference
-
setDefault
Sets the default value for the float-valued preference with the given name.Note that the current value of the preference is affected if the preference's current value was its old default value, in which case it changes to the new default value. If the preference's current is different from its old default value, its current value is unaffected. No property change events are reported by changing default values.
- Parameters:
name
- the name of the preferencevalue
- the new default value for the preference
-
setDefault
Sets the default value for the integer-valued preference with the given name.Note that the current value of the preference is affected if the preference's current value was its old default value, in which case it changes to the new default value. If the preference's current is different from its old default value, its current value is unaffected. No property change events are reported by changing default values.
- Parameters:
name
- the name of the preferencevalue
- the new default value for the preference
-
setDefault
Sets the default value for the long-valued preference with the given name.Note that the current value of the preference is affected if the preference's current value was its old default value, in which case it changes to the new default value. If the preference's current is different from its old default value, its current value is unaffected. No property change events are reported by changing default values.
- Parameters:
name
- the name of the preferencevalue
- the new default value for the preference
-
setDefault
Sets the default value for the string-valued preference with the given name.Note that the current value of the preference is affected if the preference's current value was its old default value, in which case it changes to the new default value. If the preference's current is different from its old default value, its current value is unaffected. No property change events are reported by changing default values.
- Parameters:
name
- the name of the preferencedefaultObject
- the new default value for the preference
-
setDefault
Sets the default value for the boolean-valued preference with the given name.Note that the current value of the preference is affected if the preference's current value was its old default value, in which case it changes to the new default value. If the preference's current is different from its old default value, its current value is unaffected. No property change events are reported by changing default values.
- Parameters:
name
- the name of the preferencevalue
- the new default value for the preference
-
setToDefault
Sets the current value of the preference with the given name back to its default value.Note that the preferred way of re-initializing a preference to the appropriate default value is to call
setToDefault
. This is implemented by removing the named value from the store, thereby exposing the default value.- Parameters:
name
- the name of the preference
-
setValue
Sets the current value of the double-valued preference with the given name.A property change event is reported if the current value of the preference actually changes from its previous value. In the event object, the property name is the name of the preference, and the old and new values are wrapped as objects.
Note that the preferred way of re-initializing a preference to its default value is to call
setToDefault
.- Parameters:
name
- the name of the preferencevalue
- the new current value of the preference
-
setValue
Sets the current value of the float-valued preference with the given name.A property change event is reported if the current value of the preference actually changes from its previous value. In the event object, the property name is the name of the preference, and the old and new values are wrapped as objects.
Note that the preferred way of re-initializing a preference to its default value is to call
setToDefault
.- Parameters:
name
- the name of the preferencevalue
- the new current value of the preference
-
setValue
Sets the current value of the integer-valued preference with the given name.A property change event is reported if the current value of the preference actually changes from its previous value. In the event object, the property name is the name of the preference, and the old and new values are wrapped as objects.
Note that the preferred way of re-initializing a preference to its default value is to call
setToDefault
.- Parameters:
name
- the name of the preferencevalue
- the new current value of the preference
-
setValue
Sets the current value of the long-valued preference with the given name.A property change event is reported if the current value of the preference actually changes from its previous value. In the event object, the property name is the name of the preference, and the old and new values are wrapped as objects.
Note that the preferred way of re-initializing a preference to its default value is to call
setToDefault
.- Parameters:
name
- the name of the preferencevalue
- the new current value of the preference
-
setValue
Sets the current value of the string-valued preference with the given name.A property change event is reported if the current value of the preference actually changes from its previous value. In the event object, the property name is the name of the preference, and the old and new values are wrapped as objects.
Note that the preferred way of re-initializing a preference to its default value is to call
setToDefault
.- Parameters:
name
- the name of the preferencevalue
- the new current value of the preference
-
setValue
Sets the current value of the boolean-valued preference with the given name.A property change event is reported if the current value of the preference actually changes from its previous value. In the event object, the property name is the name of the preference, and the old and new values are wrapped as objects.
Note that the preferred way of re-initializing a preference to its default value is to call
setToDefault
.- Parameters:
name
- the name of the preferencevalue
- the new current value of the preference
-