All Superinterfaces:

Cloneable, Serializable

All Known Subinterfaces:

AggregationFunction, DynamicExpression, FieldAggregationFunction, Function, LayoutProcessorFunction, OutputFunction, StructureFunction, ValidateableExpression

All Known Implementing Classes:

AbstractCompareExpression, AbstractElementFormatFunction, AbstractExpression, AbstractFunction, AndExpression, AttributeExpressionsEvaluator, AverageExpression, BSFExpression, BSHExpression, CapitalizeStringExpression, CellFormatFunction, ColumnAggregationExpression, ColumnAverageExpression, ColumnDifferenceExpression, ColumnDivisionExpression, ColumnMaximumExpression, ColumnMinimumExpression, ColumnMultiplyExpression, ColumnSumExpression, CompareDateExpression, CompareFieldsExpression, CompareNumberExpression, CompareStringExpression, ConditionalItemSumFunction, ConvertToDateExpression, ConvertToNumberExpression, CountDistinctFunction, CreateGroupAnchorsFunction, CreateHyperLinksFunction, CrosstabColumnSequenceFunction, CrosstabProcessorFunction, CSVWriter, DateCutExpression, DateExpression, DateSpanExpression, DefaultOutputFunction, ElementColorFunction, ElementTrafficLightFunction, ElementVisibilityFunction, ElementVisibilitySwitchFunction, EventMonitorFunction, FastExportOutputFunction, FormulaExpression, FormulaFunction, GetDataRowValueExpression, GroupCountFunction, HideElementByNameFunction, HideElementIfDataAvailableExpression, HideNullValuesFunction, HidePageBandForTableExportFunction, IsEmptyDataExpression, IsEmptyExpression, IsExportTypeExpression, IsNegativeExpression, IsNullExpression, IsPositiveExpression, ItemAvgFunction, ItemColumnQuotientExpression, ItemCountFunction, ItemHideFunction, ItemMaxFunction, ItemMinFunction, ItemPercentageFunction, ItemSumFunction, MapIndirectExpression, MapStringExpression, MessageFormatExpression, MetaDataStyleEvaluator, NegativeNumberPaintChangeFunction, OrExpression, PageFunction, PageItemCountFunction, PageItemSumFunction, PageOfPagesFunction, PageTotalFunction, PaintComponentFunction, PaintDynamicComponentFunction, PercentageExpression, ResourceBundleLookupExpression, ResourceMesssageFormatExpression, RowBandingFunction, SheetNameFunction, ShowElementByNameFunction, ShowElementIfDataAvailableExpression, SingleValueQueryFunction, StyleExpressionsEvaluator, StyleResolvingEvaluator, SubStringExpression, SurveyScaleExpression, TextFormatExpression, TokenizeStringExpression, ToLowerCaseStringExpression, TotalCalculationFunction, TotalGroupCountFunction, TotalGroupSumFunction, TotalGroupSumQuotientFunction, TotalGroupSumQuotientPercentFunction, TotalItemCountFunction, TotalItemMaxFunction, TotalItemMinFunction, TotalPageItemCountFunction, TotalPageSumFunction, ToUpperCaseStringExpression, TriggerPageFooterFunction, URLEncodeExpression, VariableDateExpression, WizardItemHideFunction, XMLWriter
```
public interface Expression
extends Cloneable, Serializable
```
An expression is a lightweight function 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.

Author:

Thomas Morgner

Method Summary

All Methods Instance Methods Abstract Methods Deprecated Methods
Modifier and Type	Method	Description
`Object`	`clone()`	Clones the expression, expression should be reinitialized after the cloning.
`DataRow`	`getDataRow()`	Returns the DataRow used in this expression.
`int`	`getDependencyLevel()`	The dependency level defines the level of execution for this function.
`Expression`	`getInstance()`	Return a new instance of this expression.
`String`	`getName()`	Returns the name of the expression.
`org.pentaho.reporting.libraries.base.config.Configuration`	`getReportConfiguration()`	Returns the report's current configuration.
`ResourceBundleFactory`	`getResourceBundleFactory()`	Returns the resource-bundle factory of the report.
`ExpressionRuntime`	`getRuntime()`	Retrieves the runtime instance.
`Object`	`getValue()`	Return the current expression value.
`boolean`	`isActive()`	Deprecated. The Active-Flag is no longer evaluated.
`boolean`	`isDeepTraversing()`	Checks whether this expression is a deep-traversing expression.
`boolean`	`isPreserve()`	Checks whether this expression's last value is preserved after the expression goes out of scope.
`void`	`setDependencyLevel(int level)`	Sets the dependency level for the expression.
`void`	`setName(String name)`	Sets the name of the expression.
`void`	`setRuntime(ExpressionRuntime runtime)`	Defines the DataRow used in this expression.

- Method Detail
  - getName
```
String getName()
```
    Returns the name of the expression.
    Every expression, function and column in the datamodel within a report is required to have a unique name.
    
    Returns:
    
    the function name.
  - setName
```
void setName(String name)
```
    Sets the name of the expression.
    The name must not be null and must be unique within the expressions of the report, if you intend to use this as a global expression. Expressions for style-expressions or attribute-expressions can work without a name.
    
    Parameters:
    
    name - the name.
  - getValue
```
Object getValue()
```
    Return the current expression value.
    The value depends (obviously) on the expression implementation.
    
    Returns:
    
    the value of the function.
  - isActive
```
boolean isActive()
```
    Deprecated.
    The Active-Flag is no longer evaluated. We always assume it to be true.
    
    Returns true if this expression contains autoactive content and should be called by the system, regardless whether this expression is referenced in the datarow.
    
    Returns:
    
    true, if the expression is activated automaticly, false otherwise.
  - getDataRow
```
DataRow getDataRow()
```
    Returns the DataRow used in this expression. The dataRow is set when the report processing starts and can be used to access the values of functions, expressions and the reports datasource.
    
    Returns:
    
    the assigned DataRow for this report processing.
  - clone
```
Object clone()
      throws CloneNotSupportedException
```
    Clones the expression, expression should be reinitialized after the cloning.
    Expression maintain no state, cloning is done at the beginning of the report processing to disconnect the used expression from any other object space.
    
    Returns:
    
    A clone of this expression.
    
    Throws:
    
    CloneNotSupportedException - this should never happen.
  - getDependencyLevel
```
int getDependencyLevel()
```
    The dependency level defines the level of execution for this function. Higher dependency functions are executed before lower dependency functions. For ordinary functions and expressions, the range for dependencies is defined to start from 0 (lowest dependency possible) to 2^31 (upper limit of int).
    Levels below 0 are reserved for system-functionality (printing and layouting).
    The level must not change during the report processing, or the result is invalid.
    
    Returns:
    
    the level.
  - setDependencyLevel
```
void setDependencyLevel(int level)
```
    Sets the dependency level for the expression.
    
    Parameters:
    
    level - the level.
  - getInstance
```
Expression getInstance()
```
    Return a new instance of this expression. The copy is initialized and uses the same parameters as the original, but does not share any objects.
    
    Returns:
    
    a copy of this function.
  - getResourceBundleFactory
```
ResourceBundleFactory getResourceBundleFactory()
```
    Returns the resource-bundle factory of the report. This factory encapsulates the Locale and allows to create a resource-bundle in a implementation-independent way.
    
    Returns:
    
    the resource-bundle factory.
  - getReportConfiguration
```
org.pentaho.reporting.libraries.base.config.Configuration getReportConfiguration()
```
    Returns the report's current configuration.
    
    Returns:
    
    the configuration of the report.
  - setRuntime
```
void setRuntime(ExpressionRuntime runtime)
```
    Defines the DataRow used in this expression. The dataRow is set when the report processing starts and can be used to access the values of functions, expressions and the reports datasource.
    
    Parameters:
    
    runtime - the runtime information for the expression
  - getRuntime
```
ExpressionRuntime getRuntime()
```
    Retrieves the runtime instance.
    
    Returns:
    
    the runtime, can be null, if the expression is abused outside of the report processing.
  - isDeepTraversing
```
boolean isDeepTraversing()
```
    Checks whether this expression is a deep-traversing expression. Deep-traversing expressions receive events from all sub-reports.
    
    Returns:
    
    the deep-traversing flag.
  - isPreserve
```
boolean isPreserve()
```
    Checks whether this expression's last value is preserved after the expression goes out of scope.
    
    Returns:
    
    true, if the expression's last value is preserved, false otherwise.

Interface Expression

Method Summary

Method Detail

getName

setName

getValue

isActive

getDataRow

clone

getDependencyLevel

setDependencyLevel

getInstance

getResourceBundleFactory

getReportConfiguration

setRuntime

getRuntime

isDeepTraversing

isPreserve