Brief introduction of custom function

1.1 Application scenario

FineBI has provided a large number of self-contained functions, which are sufficient to meet users' template creation needs under normal circumstances, but in some special areas, some special functions may be required, in this case, FineBI provides custom functions, which can be defined by users themselves according to business needs, but these functions must meet FineBI function definition rules.

Note: Only extracted data is supported.

1.2 Scope of use

• Only the extracted data version is supported.

• Does not support custom aggregation class functions, such as aggregation functions、quick calculation functions.

1.3 Definition rules

FineBI function definition rules: Functionname(Para,Para,...) where Functionname is the function name and Para is the parameter.

In FineBI, each function is defined as a class, which must implement the Function interface, and the class is first reflected by the function name and then its run(Object[] agrs) method is called.

Take the SUM function as an example, the SUM class is used to calculate the SUM function and inherits from the AbstractFunction class, which implements the Function interface.

When the function operates, it first obtains the class of the function according to the function name, such as SUM(2,4, true), which first obtains the class SUM according to the function name, and then calls the run(Object[] args) method of the SUM class. args stores the arguments of the SUM function, which can be obtained from args to perform the operation. For example, the result isSUM(2,4,true)=2+4+1=7。

SUM function used in the code.

package com.fr.report.script;
import com.fr.general.FArray;
import com.fr.script.AbstractFunction;
public class CSUM extends AbstractFunction {
public Object run(Object[] args) {
double result = 0;
for (int i = 0; i < args.length; i++) {
if (args[i] == null) {
continue;
}
result += parseObject(args[i]);
}
return result;
}
private double parseObject(Object obj) {
if (obj instanceof Number) {
return ((Number) obj).doubleValue();
} else if (obj instanceof Boolean) {
return ((Boolean) obj).booleanValue() ? 1 : 0;
} else if (obj instanceof FArray) {
FArray array = (FArray) obj;
double sum = 0;
for (int i = 0; i < array.length(); i++) {
sum += parseObject(array.elementAt(i));
}
return sum;
} else if (obj != null) {
try {
return Double.parseDouble(obj.toString());
} catch (NumberFormatException exp) {
return 0;
}
}
return 0;
}
}

1.4 Compile environment preparation

For more information, see Compiling Java Programs.

A simple custom function example is used to illustrate the use of custom functions.

Define a function StringCat that serves to concatenate all parameters as strings.

For more details, see Custom Functions for String Concatenation.

1）Custom function names are based on class filenames.

2）Custom function filenames support English only, including pure upper case, pure lower case, mixed case input.

3）The added functions are shown in "Other Functions".

4）Currently, mixed case input is not supported.