/*****************************************************************************
SQLJEP - Java SQL Expression Parser 0.2
November 1 2006
(c) Copyright 2006, Alexey Gaidukov
SQLJEP Author: Alexey Gaidukov
SQLJEP is based on JEP 2.24 (http://www.singularsys.com/jep/)
(c) Copyright 2002, Nathan Funk
See LICENSE.txt for license information.
*****************************************************************************/
package com.meidusa.amoeba.sqljep.function;
import com.meidusa.amoeba.sqljep.function.PostfixCommand;
import com.meidusa.amoeba.sqljep.ASTFunNode;
import com.meidusa.amoeba.sqljep.JepRuntime;
import com.meidusa.amoeba.sqljep.ParseException;
public class Concat extends PostfixCommand {
final public int getNumberOfParameters() {
return 2;
}
/**
* Calculates the result of applying the "||" operator to the arguments from
* the stack and pushes it back on the stack.
*/
public Comparable<?>[] evaluate(ASTFunNode node, JepRuntime runtime) throws ParseException {
node.childrenAccept(runtime.ev, null);
Comparable<?> param2 = runtime.stack.pop();
Comparable<?> param1 = runtime.stack.pop();
return new Comparable<?>[]{param1,param2};
}
public static String concat(Comparable<?> param1, Comparable<?> param2) throws ParseException {
if (param1 == null) {
return (param2 != null) ? param2.toString() : null;
}
if (param2 == null) {
return (param1 != null) ? param1.toString() : null;
}
return param1.toString().concat(param2.toString());
}
public static String concat(Comparable<?> param1, Comparable<?> param2,Comparable<?> param3) throws ParseException {
if (param1 == null) {
return concat(param2,param3);
}
if (param2 == null) {
return concat(param1,param3);
}
if (param3 == null) {
return concat(param1,param2);
}
return concat(param1,param2).concat(param3.toString());
}
public Comparable<?> getResult(Comparable<?>... comparables)
throws ParseException {
Comparable<?> param2 = comparables[1];
Comparable<?> param1 = comparables[0];
return (concat(param1, param2));
}
}