Client Tools Guide › Unique User ID (UUID) Menu › UUID Indexing Functions › User-Defined Functions

User-Defined Functions

It is possible for users to define and implement their own functions.

The declaration of such functions is done in an XML file named “userJarsDef.xml”. The format of the file is:

[set the jars variable for your book]
 <indexFunction
jarFilename="c:\dev\uuid\userJar.jar"
implClass="EvalSubstring"
function="UserPrivateSubstring" />
</jars>

The function implementation is expected to be found in the specified JAR file. The specified class should extend the class:

com.eurekify.matcher.indexer.evalfunctions. EvalFunc

The default-constructor of the class should define the number parameters this function accepts:

numberOfParameters = 1;

The class should implement the method:

public void run(Stack<Object> stack) throws eurekifyEvaluationException

First the stack needs to be checked with the function

checkTheStack(stack);

The parameters passed to the function are retrieved from the stack using:

String strParam = getStringParam(stack);

Or:

int intParam = getIntParam(stack);

The result of the function should be pushed back to the stack using

stack.push(result);

Example implementation class:

import java.util.Stack;
import com.eurekify.matcher.indexer.evalfunctions.*;
public classEvalSubstring extends EvalFunc {
public EvalSubstring() {
numberOfParameters = 3;
}
public void run(Stack<Object> inStack) throws eurekifyEvaluationException
{
// check the stack
checkTheStack(inStack);
// get the parameter from the stack
int to = getIntParam(inStack);
int from = getIntParam(inStack);
String str = getStringParam(inStack);

String result = str.substring(from, to);
// push the result on the stack
inStack.push(result);
}
}