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An expression is a lightweight computation that does not maintain a state. Expressions are used to calculate values within a single row of a report. Expressions can use a dataRow to access other fields, expressions or functions within the current row in the report. Statefull computations can be implemented using functions.
Function
Method Summary | |
java.lang.Object |
clone()
Clones the expression, expression should be reinitialized after the cloning. |
java.lang.Object |
computeValue()
Return the current expression value. |
Expression |
getInstance()
Return a new instance of this expression. |
java.lang.String |
getName()
Returns the name of the expression. |
boolean |
isDeepTraversing()
A deep-traversing expression declares that it should receive updates from all subreports. |
boolean |
isPrecompute()
Returns, whether the expression will be precomputed. |
boolean |
isPreserve()
Checks, whether the expression's result should be preserved in the precomputed value registry. |
void |
setDeepTraversing(boolean deepTraversing)
Defines, whether the expression is deep-traversing. |
void |
setName(java.lang.String name)
Sets the name of the expression. |
void |
setPrecompute(boolean precompute)
Defines, whether the expression will be precomputed. |
void |
setPreserve(boolean preserve)
Defines, whether the expression's result should be preserved in the precomputed value registry. |
void |
setRuntime(ExpressionRuntime runtime)
Defines the DataRow used in this expression. |
Method Detail |
public java.lang.String getName()
public void setName(java.lang.String name)
name
- the name.public java.lang.Object computeValue() throws DataSourceException
The value depends (obviously) on the expression implementation.
DataSourceException
public java.lang.Object clone() throws java.lang.CloneNotSupportedException
Expression maintain no state, cloning is done at the beginning of the report processing to disconnect the used expression from any other object space.
java.lang.CloneNotSupportedException
- this should never happen.public Expression getInstance()
public void setRuntime(ExpressionRuntime runtime)
runtime
- the runtime information for the expressionpublic boolean isDeepTraversing()
public void setDeepTraversing(boolean deepTraversing)
deepTraversing
- true, if the expression is deep-traversing, false
otherwise.public boolean isPrecompute()
public void setPrecompute(boolean precompute)
precompute
- true, if the expression is precomputed, false otherwise.public boolean isPreserve()
public void setPreserve(boolean preserve)
preserve
- true, if the expression's results should be preserved,
false otherwise.
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