/*****************************************************************************
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 Substring extends PostfixCommand {
private static final String PARAM_EXCEPTION = "BeginIndex and CountChars in substr shoud be integers";
final public int getNumberOfParameters() {
return -1;
}
public Comparable<?>[] evaluate(ASTFunNode node, JepRuntime runtime) throws ParseException {
node.childrenAccept(runtime.ev, null);
int num = node.jjtGetNumChildren();
if (num == 2) {
Comparable<?> param2 = runtime.stack.pop();
Comparable<?> param1 = runtime.stack.pop();
return new Comparable<?>[]{param1,param2};
}
else if (num == 3) {
Comparable<?> param3 = runtime.stack.pop();
Comparable<?> param2 = runtime.stack.pop();
Comparable<?> param1 = runtime.stack.pop();
return new Comparable<?>[]{param1,param2,param3};
} else {
// remove all parameters from stack and push null
removeParams(runtime.stack, num);
throw new ParseException(PARAMS_NUMBER+" for substr");
}
}
public static String substr(Comparable<?> param1, Comparable<?> param2) throws ParseException {
if (param1 == null) {
return null;
}
try {
int beginIndex = getInteger(param2)-1;
return param1.toString().substring(beginIndex);
} catch (ParseException e) {
throw new ParseException(PARAM_EXCEPTION);
} catch (StringIndexOutOfBoundsException e) {
return null;
}
}
public static String substr(Comparable<?> param1, Comparable<?> param2, Comparable<?> param3) throws ParseException {
if (param1 == null) {
return null;
}
try {
int beginIndex = getInteger(param2)-1;
int count = getInteger(param3);
String source = param1.toString();
if (beginIndex < 0) {
beginIndex += source.length()+1;
}
return source.substring(beginIndex,beginIndex+count);
} catch (ParseException e) {
throw new ParseException(PARAM_EXCEPTION);
} catch (StringIndexOutOfBoundsException e) {
return null;
}
}
public Comparable<?> getResult(Comparable<?>... comparables)
throws ParseException {
if(comparables.length == 2){
return substr(comparables[0],comparables[1]);
}else{
return substr(comparables[0],comparables[1],comparables[2]);
}
}
}