JReport Designer supports a multiple-value field, which contains a set of values in a single field, in a formula. Using the multiple value field is the same as using an array in a formula. You can refer to a field with multiple values as with a normal field in a formula, such as @FIELDNAME, and then use the array functions that JReport Designer provides in the Formula Editor to manipulate the values in it. JReport Designer first converts this field into a normal array, and then manipulates it in the usual way.
For example, normally an array in a formula is manually defined as follows:
Integer myArray[4]=[1, 2, 3, 4]; //Datatype ArrayName[ArraySize]=[ArrayContent];
The array may be referred to in this way:
integer myInt=3;
myInt in myArray;
If a field, named myField, for example, contains a similar array value, it can be referred to similarly:
integer myInt=3;
myInt in @myField;