com.aspose.cells

Class AbstractCalculationEngine

java.lang.Object

com.aspose.cells.AbstractCalculationEngine

public abstract class AbstractCalculationEngine
extends java.lang.Object

Represents user's custom calculation engine to extend the default calculation engine of Aspose.Cells.

Remarks

User should not modify any part of the Workbook directly in this implementation(except the calculated result of the custom function, which can be set by CalculationData.CalculatedValue property). Otherwise unexpected result or Exception may be caused. If user needs to change other data than calculated result in the implementation for some custom functions, for example, change cell's formula, style, ...etc., user should gather those data in this implementation and change them out of the scope of formula calculation.

Example

 
         class MyEngine extends AbstractCalculationEngine
         {
             public /*override*/ void calculate(CalculationData data)
             {
                 String funcName = data.getFunctionName().toUpperCase();
                 if ("MYFUNC".equals(funcName))
                 {
                     //do calculation for MYFUNC here
                     int count = data.getParamCount();
                     Object res = null;
                     for (int i = 0; i <count; i++)
                     {
                         Object pv = data.getParamValue(i);
                         if (pv instanceof ReferredArea)
                         {
                             ReferredArea ra = (ReferredArea)pv;
                             pv = ra.getValue(0, 0);
                         }
                         //process the parameter here
                         //res = ...;
                     }
                     data.setCalculatedValue(res);
                 }
             }
         }
         Workbook wb = new Workbook("custom_calc.xlsx");
         CalculationOptions opts = new CalculationOptions();
         opts.setCustomEngine(new MyEngine());
         wb.calculateFormula(opts);
 
 

Constructor Summary

Constructors

Constructor and Description
AbstractCalculationEngine()

Method Summary

Methods

Modifier and Type	Method and Description
abstract void	calculate(CalculationData data) Calculates one function with given data.
boolean	forceRecalculate(java.lang.String functionName) Whether force given function to be recalculated always when calculating shared formulas.
boolean	getProcessBuiltInFunctions() Whether built-in functions that have been supported by the built-in engine should be checked and processed by this implementation.
boolean	isParamArrayModeRequired() Indicates whether this engine needs the parameter to be calculated in array mode.
boolean	isParamLiteralRequired() Indicates whether this engine needs the literal text of parameter while doing calculation.
protected void	skipCalculation() Skips the calculation for the entire formula that references to the function currently under evaluation.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

AbstractCalculationEngine

public AbstractCalculationEngine()

Method Detail

calculate

public abstract void calculate(CalculationData data)

Calculates one function with given data.

Remarks

User should set the calculated value for given data for all functions(including excel native functions) that he wants to calculate by himself in this implementation.

Parameters:

data - the required data to calculate function such as function name, parameters, ...etc.

isParamLiteralRequired

public boolean isParamLiteralRequired()

Indicates whether this engine needs the literal text of parameter while doing calculation. Default value is false.

Remarks

If this custom calculation engine needs the parameter's literal text, more stacks will be required to cache the literal text for parameters and Calculate() method may be called recursively to calculate the parameter's value. Generally the literal text is not needed for calculating formulas and this property should be kept as false for most implementations to get better performance.

isParamArrayModeRequired

public boolean isParamArrayModeRequired()

Indicates whether this engine needs the parameter to be calculated in array mode. Default value is false. If CalculationData.getParamValueInArrayMode(int,int,int) is required when calculating custom functions and user has not updated the definition for them (by Workbook.updateCustomFunctionDefinition(CustomFunctionDefinition)), this property needs to be set as true.

Remarks

If this custom calculation engine needs the parameter to be calculated in array mode, more stacks will be required to cache the tree for parameters and Calculate() method may be called recursively to calculate the parameter's value. For performance consideration, please keep this property as the default value(false) if there is no special requirement.

getProcessBuiltInFunctions

public boolean getProcessBuiltInFunctions()

Whether built-in functions that have been supported by the built-in engine should be checked and processed by this implementation. Default is false.

Remarks

If user needs to change the calculation logic of some built-in functions, this property should be set as true. Otherwise please leave this property as false for performance consideration.

forceRecalculate

public boolean forceRecalculate(java.lang.String functionName)

Whether force given function to be recalculated always when calculating shared formulas.

Remarks

For shared formulas, multiple cells share the same function. If the function's parameters keep same for those cells too, then generally this function needs to be calculated only once. So for performance consideration we only calculate such kind of function once too(calculate(CalculationData) is called only once, instead of being called repeatedly for every cell). However, for user's custom implementation, maybe the function, especially the custom function, needs to be calculated differently for different cells. If so, user needs to override this method to make it return true for the function. And for calculate(CalculationData), the given CalculationData.getCalculatedValue() may have been initialized with the cached value of previous calculation.

Parameters:

functionName - name of the function. Generally it is custom function's name. If getProcessBuiltInFunctions() is true, then built-in functions will also be checked here.

Returns:

true if the specified function needs to be recalculated always.

skipCalculation

protected void skipCalculation()

Skips the calculation for the entire formula that references to the function currently under evaluation.

Remarks

This method can be invoked in the implementation of calculate(CalculationData) to skip the calculation for the entire formula and the original value of the formula will be kept without change.