package com.opensymphony.xwork2.util;
import org.apache.commons.lang3.StringUtils;
/**
* OGNL implementation of {@link TextParser}
*/
public class OgnlTextParser implements TextParser {
public Object evaluate(char[] openChars, String expression, TextParseUtil.ParsedValueEvaluator evaluator, int maxLoopCount) {
// deal with the "pure" expressions first!
//expression = expression.trim();
Object result = expression = (expression == null) ? "" : expression;
int pos = 0;
for (char open : openChars) {
int loopCount = 1;
//this creates an implicit StringBuffer and shouldn't be used in the inner loop
final String lookupChars = open + "{";
while (true) {
int start = expression.indexOf(lookupChars, pos);
if (start == -1) {
loopCount++;
start = expression.indexOf(lookupChars);
}
if (loopCount > maxLoopCount) {
// translateVariables prevent infinite loop / expression recursive evaluation
break;
}
int length = expression.length();
int x = start + 2;
int end;
char c;
int count = 1;
while (start != -1 && x < length && count != 0) {
c = expression.charAt(x++);
if (c == '{') {
count++;
} else if (c == '}') {
count--;
}
}
end = x - 1;
if ((start != -1) && (end != -1) && (count == 0)) {
String var = expression.substring(start + 2, end);
Object o = evaluator.evaluate(var);
String left = expression.substring(0, start);
String right = expression.substring(end + 1);
String middle = null;
if (o != null) {
middle = o.toString();
if (StringUtils.isEmpty(left)) {
result = o;
} else {
result = left.concat(middle);
}
if (StringUtils.isNotEmpty(right)) {
result = result.toString().concat(right);
}
expression = left.concat(middle).concat(right);
} else {
// the variable doesn't exist, so don't display anything
expression = left.concat(right);
result = expression;
}
pos = (left != null && left.length() > 0 ? left.length() - 1: 0) +
(middle != null && middle.length() > 0 ? middle.length() - 1: 0) +
1;
pos = Math.max(pos, 1);
} else {
break;
}
}
}
return result;
}
}