Update 26-Apr-2015:Added 2 examples: Delimited string to context values and the reverse way.
Update 25-Apr-2015:Added DisplayQueue screenshots.
Introduction
UDF can be written for many different purpose, and with many different way of coding. Still, there should be some reusable coding/statement/patterns that keep on occurs again and again. In this document, is my attempt to list down some common coding/statement and patterns that known. Below meant to be building blocks, mean not use it standalone, and should mix and match with other building blocks to come out something useful. It just like LEGO 
Category | Requirement | UDF coding |
| Condition | Test if input field existed (not null). This should be first checking for value, if null then do nothing. | if (value != null) |
Condition | Test if context values existed (not null). This should be first checking for contextValues, if empty context(null) then do nothing. | if (contextValues != null && contextValues.length > 0) |
Condition | Test if has value (non-empty). | if (value != null && value.trim().length() > 0) |
Condition | Test if value is suppress. | if (ResultList.SUPPRESS.equalsIgnoreCase(value))) |
Condition | Test if value is context change. | if (ResultList.CC.equals(value)) |
ResultList | Add suppress to result. | result.addSuppress(); |
ResultList | Add context change to result. | result.addContextChange(); |
ResultList | Add value to result. | result.addValue(value); |
ResultList | Add boolean true/false to result. Boolean value will be used in next function call. | result.addValue("true"); |
ResultList | Add empty string to result. Empty string will create target node. | result.addValue(""); |
ArrayList | Create new array list. | List array = new ArrayList(); |
ArrayList | Add value to array. | array.add(value); |
ArrayList | Test if array contains value. | if (array.contains(value)) |
Looping Pattern | Single loop at contextValues, get each value to do something. | for (int i = 0; i < contextValues.length; i++){ String value = contextValues[i]; //Do something |
Looping Pattern | Create target node if some condition is met. Suggested function name: createIf<SomeConditions> | for (int i = 0; i < contextValues.length; i++){ String value = contextValues[i]; result.addValue(""); } else{ result.addSuppress(); } |
| Looping Pattern | Pass value to target node if some condition is met.
Suggested function name: passIf<SomeConditions> | for (int i = 0; i < contextValues.length; i++){ String value = contextValues[i]; result.addValue(value); } else{ result.addSuppress(); } |
| Looping Pattern | Return true if some condition is met, otherwise false.
Suggested function name: | for (int i = 0; i < contextValues.length; i++){ String value = contextValues[i]; result.addValue("true"); } else{ result.addValue("false"); } |
| Looping Pattern | Return single true if some condition is met for values in context, otherwise single false. Suggested function name:
contextHas<SomeConditions> | String conditionMet = "false"; for (int i = 0; i < contextValues.length; i++){ String value = contextValues[i]; conditionMet = "true"; break; } result.addValue(conditionMet); |
| Looping Pattern | Outer and inner loop at contextValues and secondContext, get both outer and inner value to compare and do something. | for (int i = 0; i < contextValues.length; i++){
String value2 = secondContext[j]; //Do something } |
| Position | Get value from contextValues based on index/position.
Suggested function name: getValueByIndex getLastValue | input1 = contextValues
by index --> result.addValue(contextValues[index-1]); last --> result.addValue(contextValues[contextValues.length-1]); |
| Context | Split each value in contexts with context change. Simulate splitByValue(ForEach).
| for (int i = 0; i < contextValues.length; i++){ String value = contextValues[i];
result.addValue(value);
if(i != contextValues.length - 1){ result.addContextChange(); } } |
| Context | Remove all context change in contextValues. Simulate removeContext.
| for (int i = 0; i < contextValues.length; i++){
String value = contextValues[i];
if (!ResultList.CC.equals(value)){ result.addValue(value); } } |
| Context | Return only unique values, remove duplicated values. | List uniqueList = new ArrayList(); for (int i = 0; i < contextValues.length; i++){ String value = contextValues[i]; if (!uniqueList.contains(value)) { uniqueList.add(value); result.addValue(value); } |
| Context | Split input1 full string to context values by delimiter specified by input2. | input1 = fullString input2 = delimiter String dchar = delimiter[0];
for (int i = 0; i < fullString.length; i++){
String[] splitString = fullString[i].split(dchar);
for (int j = 0; j < splitString.length; j++) { result.addValue(splitString[j]); } } |
| Context | Concatenate input1 context values to delimited string by delimiter specified by input2.
| input1 =contextValues input2 = delimiter
String fullString = ""; String dchar = delimiter[0]; for (int i = 0; i < contextValues.length; i++){ String value = contextValues[i]; if(i == 0){ fullString = value; } else{ fullString = fullString + dchar + value; } }
result.addValue(fullString); |
