/*
* Copyright 2002-2006,2009 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.opensymphony.xwork2.util;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.conversion.impl.XWorkConverter;
import com.opensymphony.xwork2.inject.Container;
import java.util.HashSet;
import java.util.Set;
import org.apache.commons.lang.StringUtils;
/**
* Utility class for text parsing.
*
* @author Jason Carreira
* @author Rainer Hermanns
* @author tm_jee
*
* @version $Date$ $Id$
*/
public class TextParseUtil {
private static final int MAX_RECURSION = 1;
/**
* Converts all instances of ${...}, and %{...} in <code>expression</code> to the value returned
* by a call to {@link ValueStack#findValue(java.lang.String)}. If an item cannot
* be found on the stack (null is returned), then the entire variable ${...} is not
* displayed, just as if the item was on the stack but returned an empty string.
*
* @param expression an expression that hasn't yet been translated
* @return the parsed expression
*/
public static String translateVariables(String expression, ValueStack stack) {
return translateVariables(new char[]{'$', '%'}, expression, stack, String.class, null).toString();
}
/**
* Function similarly as {@link #translateVariables(char, String, ValueStack)}
* except for the introduction of an additional <code>evaluator</code> that allows
* the parsed value to be evaluated by the <code>evaluator</code>. The <code>evaluator</code>
* could be null, if it is it will just be skipped as if it is just calling
* {@link #translateVariables(char, String, ValueStack)}.
*
* <p/>
*
* A typical use-case would be when we need to URL Encode the parsed value. To do so
* we could just supply a URLEncodingEvaluator for example.
*
* @param expression
* @param stack
* @param evaluator The parsed Value evaluator (could be null).
* @return the parsed (and possibly evaluated) variable String.
*/
public static String translateVariables(String expression, ValueStack stack, ParsedValueEvaluator evaluator) {
return translateVariables(new char[]{'$', '%'}, expression, stack, String.class, evaluator).toString();
}
/**
* Converts all instances of ${...} in <code>expression</code> to the value returned
* by a call to {@link ValueStack#findValue(java.lang.String)}. If an item cannot
* be found on the stack (null is returned), then the entire variable ${...} is not
* displayed, just as if the item was on the stack but returned an empty string.
*
* @param open
* @param expression
* @param stack
* @return Translated variable String
*/
public static String translateVariables(char open, String expression, ValueStack stack) {
return translateVariables(open, expression, stack, String.class, null).toString();
}
/**
* Converted object from variable translation.
*
* @param open
* @param expression
* @param stack
* @param asType
* @return Converted object from variable translation.
*/
public static Object translateVariables(char open, String expression, ValueStack stack, Class asType) {
return translateVariables(open, expression, stack, asType, null);
}
/**
* Converted object from variable translation.
*
* @param open
* @param expression
* @param stack
* @param asType
* @param evaluator
* @return Converted object from variable translation.
*/
public static Object translateVariables(char open, String expression, ValueStack stack, Class asType, ParsedValueEvaluator evaluator) {
return translateVariables(new char[]{open} , expression, stack, asType, evaluator, MAX_RECURSION);
}
/**
* Converted object from variable translation.
*
* @param open
* @param expression
* @param stack
* @param asType
* @param evaluator
* @return Converted object from variable translation.
*/
public static Object translateVariables(char[] openChars, String expression, ValueStack stack, Class asType, ParsedValueEvaluator evaluator) {
return translateVariables(openChars, expression, stack, asType, evaluator, MAX_RECURSION);
}
/**
* Converted object from variable translation.
*
* @param open
* @param expression
* @param stack
* @param asType
* @param evaluator
* @return Converted object from variable translation.
*/
public static Object translateVariables(char open, String expression, ValueStack stack, Class asType, ParsedValueEvaluator evaluator, int maxLoopCount) {
return translateVariables(new char[]{open}, expression, stack, asType, evaluator, maxLoopCount);
}
/**
* Converted object from variable translation.
*
* @param open
* @param expression
* @param stack
* @param asType
* @param evaluator
* @return Converted object from variable translation.
*/
public static Object translateVariables(char[] openChars, String expression, ValueStack stack, Class asType, ParsedValueEvaluator evaluator, int maxLoopCount) {
// deal with the "pure" expressions first!
//expression = expression.trim();
Object result = expression;
for (char open : openChars) {
int loopCount = 1;
int pos = 0;
//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) {
pos = 0;
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 = stack.findValue(var, asType);
if (evaluator != null) {
o = evaluator.evaluate(o);
}
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;
}
}
}
XWorkConverter conv = ((Container)stack.getContext().get(ActionContext.CONTAINER)).getInstance(XWorkConverter.class);
return conv.convertValue(stack.getContext(), result, asType);
}
/**
* Returns a set from comma delimted Strings.
* @param s The String to parse.
* @return A set from comma delimted Strings.
*/
public static Set<String> commaDelimitedStringToSet(String s) {
Set<String> set = new HashSet<String>();
String[] split = s.split(",");
for (String aSplit : split) {
String trimmed = aSplit.trim();
if (trimmed.length() > 0)
set.add(trimmed);
}
return set;
}
/**
* A parsed value evaluator for {@link TextParseUtil}. It could be supplied by
* calling {@link TextParseUtil#translateVariables(char, String, ValueStack, Class, ParsedValueEvaluator)}.
*
* <p/>
*
* By supplying this <code>ParsedValueEvaluator</code>, the parsed value
* (parsed against the value stack) value will be
* given to <code>ParsedValueEvaluator</code> to be evaluated before the
* translateVariable process goes on.
*
* <p/>
*
* A typical use-case would be to have a custom <code>ParseValueEvaluator</code>
* to URL Encode the parsed value.
*
* @author tm_jee
*
* @version $Date$ $Id$
*/
public static interface ParsedValueEvaluator {
/**
* Evaluated the value parsed by Ognl value stack.
*
* @param parsedValue - value parsed by ognl value stack
* @return return the evaluted value.
*/
Object evaluate(Object parsedValue);
}
}