/**
* Recursive methods to create a {@link Function} starting from a {@link BinaryExpression} We
* consider all possible values of the left and right expressions
*
* @param pred
* @param lookupTable
* @return
*/
private Function getFunction(BinaryExpression pred, LookupTable lookupTable) {
Expression left = pred.getLeftExpression();
Expression right = pred.getRightExpression();
// left term can be function or column variable
Term t1 = null;
t1 = getFunction(left, lookupTable);
if (t1 == null) {
t1 = getVariable(left, lookupTable);
}
if (t1 == null) throw new RuntimeException("Unable to find column name for variable: " + left);
// right term can be function, column variable or data value
Term t2 = null;
t2 = getFunction(right, lookupTable);
if (t2 == null) {
t2 = getVariable(right, lookupTable);
}
if (t2 == null) {
t2 = getValueConstant(right, lookupTable);
}
// get boolean operation
String op = pred.getStringExpression();
Function funct = null;
if (op.equals("=")) funct = dfac.getFunctionEQ(t1, t2);
else if (op.equals(">")) funct = dfac.getFunctionGT(t1, t2);
else if (op.equals("<")) funct = dfac.getFunctionLT(t1, t2);
else if (op.equals(">=")) funct = dfac.getFunctionGTE(t1, t2);
else if (op.equals("<=")) funct = dfac.getFunctionLTE(t1, t2);
else if (op.equals("<>")) funct = dfac.getFunctionNEQ(t1, t2);
else if (op.equals("AND")) funct = dfac.getFunctionAND(t1, t2);
else if (op.equals("OR")) funct = dfac.getFunctionOR(t1, t2);
else if (op.equals("+")) funct = dfac.getFunctionAdd(t1, t2);
else if (op.equals("-")) funct = dfac.getFunctionSubstract(t1, t2);
else if (op.equals("*")) funct = dfac.getFunctionMultiply(t1, t2);
else if (op.equals("LIKE")) funct = dfac.getFunctionLike(t1, t2);
else throw new RuntimeException("Unknown opertor: " + op);
return funct;
}
