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Préférences
Moteurs de recherche
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JavaTM 2 Platform Std. Ed. v1.5.0
java.beans
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Constructor Summary | |
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Expression(Object value,
Object target,
String methodName,
Object[] arguments)
Creates a new Expression object for a method
that returns a result. |
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Expression(Object target,
String methodName,
Object[] arguments)
Creates a new Statement object with a target ,
methodName and arguments as per the parameters. |
Method Summary | |
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Object |
getValue()
If the value property of this instance is not already set, this method dynamically finds the method with the specified methodName on this target with these arguments and calls it. |
void |
setValue(Object value)
Sets the value of this expression to value . |
String |
toString()
Prints the value of this expression using a Java-style syntax. |
Methods inherited from class java.beans.Statement |
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execute, getArguments, getMethodName, getTarget |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Constructor Detail |
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public Expression(Object target, String methodName, Object[] arguments)
Statement
object with a target
,
methodName
and arguments
as per the parameters.
target
- The target of this expression.methodName
- The methodName of this expression.arguments
- The arguments of this expression. If null
then an empty array will be used.getValue()
public Expression(Object value, Object target, String methodName, Object[] arguments)
Expression
object for a method
that returns a result. The result will never be calculated
however, since this constructor uses the value
parameter to set the value property by calling the
setValue
method.
value
- The value of this expression.target
- The target of this expression.methodName
- The methodName of this expression.arguments
- The arguments of this expression. If null
then an empty array will be used.setValue(java.lang.Object)
Method Detail |
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public Object getValue() throws Exception
getValue
. If the value property
was already set, either by a call to setValue
or a previous call to getValue
then the value
property is returned without either looking up or calling the method.
The value property of an Expression
is set to
a unique private (non-null
) value by default and
this value is used as an internal indication that the method
has not yet been called. A return value of null
replaces this default value in the same way that any other value
would, ensuring that expressions are never evaluated more than once.
See the
excecute
method for details on how
methods are chosen using the dynamic types of the target
and arguments.
Exception
Statement.execute()
,
setValue(java.lang.Object)
public void setValue(Object value)
value
.
This value will be returned by the getValue method
without calling the method associated with this
expression.
value
- The value of this expression.getValue()
public String toString()