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Wicket is a Java web application framework that takes simplicity,
separation of concerns and ease of development to a whole new level.
Wicket pages can be mocked up, previewed and later revised using
standard WYSIWYG HTML design tools. Dynamic content processing and
form handling is all handled in Java code using a first-class
component model backed by POJO data beans that can easily be
persisted using your favorite technology.
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.wicket.core.util.string;
import org.apache.wicket.util.string.AppendingStringBuffer;
/**
* Strips comments and whitespace from javascript
*
* @author Matej Knopp
*/
public class JavaScriptStripper
{
/*
* Determines the state of script processing.
*/
/** Inside regular text */
private final static int REGULAR_TEXT = 1;
/** String started with single quote (') */
private final static int STRING_SINGLE_QUOTE = 2;
/** String started with double quotes (") */
private final static int STRING_DOUBLE_QUOTES = 3;
/** Inside two or more whitespace characters */
private final static int WHITE_SPACE = 4;
/** Inside a line comment (// ) */
private final static int LINE_COMMENT = 5;
/** Inside a multi line comment */
private final static int MULTILINE_COMMENT = 6;
/** Inside a regular expression */
private final static int REG_EXP = 7;
private int getPrevCount(String s, int fromIndex, char c)
{
int count = 0;
--fromIndex;
while (fromIndex >= 0)
{
if (s.charAt(fromIndex--) == c)
{
++count;
}
else
{
break;
}
}
return count;
}
/**
* Removes javascript comments and whitespace from specified string.
*
* @param original
* Source string
* @return String with removed comments and whitespace
*/
public String stripCommentsAndWhitespace(String original)
{
// let's be optimistic
AppendingStringBuffer result = new AppendingStringBuffer(original.length() / 2);
int state = REGULAR_TEXT;
boolean wasNewLineInWhitespace = false;
for (int i = 0; i < original.length(); ++i)
{
char c = original.charAt(i);
char next = (i < original.length() - 1) ? original.charAt(i + 1) : 0;
char prev = (i > 0) ? original.charAt(i - 1) : 0;
if (state == WHITE_SPACE)
{
// WICKET 2060
if (c == '\n' && !wasNewLineInWhitespace)
{
result.append("\n");
wasNewLineInWhitespace = true;
}
if (Character.isWhitespace(next) == false)
{
state = REGULAR_TEXT;
}
continue;
}
if (state == REGULAR_TEXT)
{
if (c == '/' && next == '/' && prev != '\\')
{
state = LINE_COMMENT;
continue;
}
else if (c == '/' && next == '*')
{
state = MULTILINE_COMMENT;
++i;
continue;
}
else if (c == '/')
{
// This might be a divide operator, or it might be a regular expression.
// Work out if it's a regular expression by finding the previous non-whitespace
// char, which
// will be either '=' or '('. If it's not, it's just a divide operator.
int idx = result.length() - 1;
while (idx > 0)
{
char tmp = result.charAt(idx);
if (Character.isWhitespace(tmp))
{
idx--;
continue;
}
if (tmp == '=' || tmp == '(' || tmp == '{' || tmp == ':' || tmp == ',' ||
tmp == '[' || tmp == ';' || tmp == '!')
{
state = REG_EXP;
break;
}
break;
}
}
else if (Character.isWhitespace(c) && Character.isWhitespace(next))
{
// WICKET-2060
if (c == '\n' || next == '\n')
{
c = '\n';
wasNewLineInWhitespace = true;
}
else
{
c = ' ';
wasNewLineInWhitespace = false;
}
// ignore all whitespace characters after this one
state = WHITE_SPACE;
}
else if (c == '\'')
{
state = STRING_SINGLE_QUOTE;
}
else if (c == '"')
{
state = STRING_DOUBLE_QUOTES;
}
result.append(c);
continue;
}
if (state == LINE_COMMENT)
{
if (c == '\n' || c == '\r')
{
state = REGULAR_TEXT;
result.append(c);
continue;
}
}
if (state == MULTILINE_COMMENT)
{
if (c == '*' && next == '/')
{
state = REGULAR_TEXT;
++i;
continue;
}
}
if (state == STRING_SINGLE_QUOTE)
{
// to leave a string expression we need even (or zero) number of backslashes
int count = getPrevCount(original, i, '\\');
if (c == '\'' && count % 2 == 0)
{
state = REGULAR_TEXT;
}
result.append(c);
continue;
}
if (state == STRING_DOUBLE_QUOTES)
{
// to leave a string expression we need even (or zero) number of backslashes
int count = getPrevCount(original, i, '\\');
if (c == '"' && count % 2 == 0)
{
state = REGULAR_TEXT;
}
result.append(c);
continue;
}
if (state == REG_EXP)
{
// to leave regular expression we need even (or zero) number of backslashes
int count = getPrevCount(original, i, '\\');
if (c == '/' && count % 2 == 0)
{
state = REGULAR_TEXT;
}
result.append(c);
}
}
return result.toString();
}
}