com.jgoodies.binding.value
Class ValueHolder
- Observable, Serializable, ValueModel
public final class ValueHolder
A simple
ValueModel
implementation
that holds a generic value.
If the value changes, a
PropertyChangeEvent
is fired
that can be observed using a
PropertyChangeListener
.
Differences in the old and new value can be checked either using
==
or
#equals
. The unbound property
identityCheckEnabled determines which mechanism is used
to check for changes in
#setValue(Object)
.
This check can be overridden for individual changes by the boolean
parameter in
#setValue(Object, boolean)
.
Constraints: The value is of type
Object
.
ValueHolder() - Constructs a
ValueHolder with null
as initial value.
|
ValueHolder(Object initialValue) - Constructs a
ValueHolder with the given initial value.
|
ValueHolder(Object initialValue, boolean checkIdentity) - Constructs a
ValueHolder with the given initial value.
|
ValueHolder(boolean initialValue) - Constructs a
ValueHolder with the specified initial
boolean value that is converted to a Boolean object.
|
ValueHolder(double initialValue) - Constructs a
ValueHolder with the specified initial
double value that is converted to a Double object.
|
ValueHolder(float initialValue) - Constructs a
ValueHolder with the specified initial
float value that is converted to a Float object.
|
ValueHolder(int initialValue) - Constructs a
ValueHolder with the specified initial
int value that is converted to an Integer object.
|
ValueHolder(long initialValue) - Constructs a
ValueHolder with the specified initial
long value that is converted to a Long object.
|
Object | getValue() - Returns the observed value.
|
boolean | isIdentityCheckEnabled() - Answers whether this ValueHolder fires value change events if
and only if the old and new value are not the same.
|
void | setIdentityCheckEnabled(boolean checkIdentity) - Sets the comparison that is used to check differences between
the old and new value when firing value change events.
|
void | setValue(Object newValue) - Sets a new value.
|
void | setValue(Object newValue, boolean checkIdentity) - Sets a new value.
|
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ValueHolder
public ValueHolder()
Constructs a ValueHolder
with null
as initial value.
ValueHolder
public ValueHolder(Object initialValue)
Constructs a ValueHolder
with the given initial value.
By default the old and new value are compared using #equals
when firing value change events.
initialValue
- the initial value
ValueHolder
public ValueHolder(Object initialValue,
boolean checkIdentity)
Constructs a ValueHolder
with the given initial value.
initialValue
- the initial valuecheckIdentity
- true to compare the old and new value using
==
, false to use #equals
ValueHolder
public ValueHolder(boolean initialValue)
Constructs a ValueHolder
with the specified initial
boolean value that is converted to a Boolean
object.
initialValue
- the initial boolean value
ValueHolder
public ValueHolder(double initialValue)
Constructs a ValueHolder
with the specified initial
double value that is converted to a Double
object.
initialValue
- the initial double value
ValueHolder
public ValueHolder(float initialValue)
Constructs a ValueHolder
with the specified initial
float value that is converted to a Float
object.
initialValue
- the initial float value
ValueHolder
public ValueHolder(int initialValue)
Constructs a ValueHolder
with the specified initial
int value that is converted to an Integer
object.
initialValue
- the initial int value
ValueHolder
public ValueHolder(long initialValue)
Constructs a ValueHolder
with the specified initial
long value that is converted to a Long
object.
initialValue
- the initial long value
getValue
public Object getValue()
Returns the observed value.
- getValue in interface ValueModel
isIdentityCheckEnabled
public boolean isIdentityCheckEnabled()
Answers whether this ValueHolder fires value change events if
and only if the old and new value are not the same.
true
if the old and new value are compared
using ==
, false
if the values
are compared using #equals
setIdentityCheckEnabled
public void setIdentityCheckEnabled(boolean checkIdentity)
Sets the comparison that is used to check differences between
the old and new value when firing value change events.
This is the default setting that is used when changing the value via
#setValue(Object)
. You can override this default setting
by changing a value via #setValue(Object, boolean)
.
checkIdentity
- true to compare the old and new value using
==
, false to use #equals
setValue
public void setValue(Object newValue)
Sets a new value. Fires a value change event if the old and new
value differ. The difference is tested with ==
if
isIdentityCheckEnabled
answers true
.
The values are compared with #equals
if the
identity check is disabled.
- setValue in interface ValueModel
setValue
public void setValue(Object newValue,
boolean checkIdentity)
Sets a new value. Fires a value change event if the old and new
value differ. The difference is tested with
==
if
checkIdentity
is
true
. The values are
compared with
#equals
if the
checkIdentiy
parameter is set to
false
.
Unlike general bean property setters, this method does not fire
an event if the old and new value are
null
.
newValue
- the new valuecheckIdentity
- true to compare the old and new value using
==
, false to use #equals
Copyright © 2002-2008 JGoodies Karsten Lentzsch. All Rights Reserved.