/* | |
* 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.myfaces.test.el; | |
import java.io.IOException; | |
import java.io.StringWriter; | |
import java.text.ParsePosition; | |
import java.util.ArrayList; | |
/** | |
* Expression Tokenizer | |
*/ | |
class ExpressionTokenizer | |
{ | |
private ExpressionTokenizer() | |
{ | |
} | |
public static String[] tokenize(CharSequence expr) | |
{ | |
final ArrayList<String> tokens = new ArrayList<String>(); | |
ParsePosition pos = new ParsePosition(0); | |
int len = expr.length(); | |
boolean sep = true; | |
while (pos.getIndex() < len) | |
{ | |
int here = pos.getIndex(); | |
char c = expr.charAt(here); | |
switch (c) | |
{ | |
case ' ': | |
next(pos); | |
break; | |
case ']': | |
throw new IllegalStateException(String.format("Position %s: unexpected '%s'", here, c)); | |
case '[': | |
tokens.add(parseIndex(expr, next(pos))); | |
break; | |
case '.': | |
if (sep) | |
{ | |
throw new IllegalStateException(String.format( | |
"Position %s: expected property, index/key, or end of expression", here)); | |
} | |
sep = true; | |
next(pos); | |
// fall through: | |
default: | |
if (!sep) | |
{ | |
throw new IllegalStateException(String.format( | |
"Position %s: expected property path separator, index/key, or end of expression", here)); | |
} | |
tokens.add(parseProperty(expr, pos)); | |
} | |
sep = false; | |
} | |
return tokens.toArray(new String[tokens.size()]); | |
} | |
private static ParsePosition next(ParsePosition pos) | |
{ | |
pos.setIndex(pos.getIndex() + 1); | |
return pos; | |
} | |
private static String parseProperty(CharSequence expr, ParsePosition pos) | |
{ | |
int len = expr.length(); | |
int start = pos.getIndex(); | |
loop: while (pos.getIndex() < len) | |
{ | |
switch (expr.charAt(pos.getIndex())) | |
{ | |
case '[': | |
case ']': | |
case '.': | |
break loop; | |
default: | |
} | |
next(pos); | |
} | |
if (pos.getIndex() > start) | |
{ | |
return expr.subSequence(start, pos.getIndex()).toString(); | |
} | |
throw new IllegalStateException(String.format("Position %s: expected property", start)); | |
} | |
/** | |
* Handles an index/key. If the text contained between [] is surrounded by a | |
* pair of " or ', these will be stripped. | |
* | |
* @param expr Expression string to tokenize | |
* @param pos current position of parser, will be updated by the method. | |
* @return token found on the position | |
*/ | |
private static String parseIndex(CharSequence expr, ParsePosition pos) | |
{ | |
int len = expr.length(); | |
int start = pos.getIndex(); | |
if (start < len) | |
{ | |
char first = expr.charAt(pos.getIndex()); | |
if (first == '"' || first == '\'') | |
{ | |
String s = parseQuotedString(expr, pos); | |
if (s != null && expr.charAt(pos.getIndex()) == ']') | |
{ | |
next(pos); | |
return s; | |
} | |
} | |
// no quoted string; match ] greedily and trim | |
while (pos.getIndex() < len) | |
{ | |
int here = pos.getIndex(); | |
try | |
{ | |
if (expr.charAt(here) == ']') | |
{ | |
return expr.subSequence(start, here).toString().trim(); | |
} | |
} | |
finally | |
{ | |
next(pos); | |
} | |
} | |
} | |
throw new IllegalStateException(String.format("Position %s: unparsable index", start)); | |
} | |
private static String parseQuotedString(CharSequence expr, ParsePosition pos) | |
{ | |
int len = expr.length(); | |
int start = pos.getIndex(); | |
if (start < len) | |
{ | |
char quote = expr.charAt(start); | |
next(pos); | |
StringWriter w = new StringWriter(); | |
while (pos.getIndex() < len) | |
{ | |
int here = pos.getIndex(); | |
char c = expr.charAt(here); | |
boolean esc = false; | |
if (c == '\\' && here + 1 < len && expr.charAt(here + 1) == quote) | |
{ | |
esc = true; | |
here = next(pos).getIndex(); | |
} | |
try | |
{ | |
// look for matching quote | |
if (c == quote && !esc) | |
{ | |
return w.toString(); | |
} | |
w.write(Character.toChars(Character.codePointAt(expr, here))); | |
} | |
catch (IOException e) | |
{ | |
throw new RuntimeException(e); | |
} | |
finally | |
{ | |
next(pos); | |
} | |
} | |
// if reached, reset due to no ending quote found | |
pos.setIndex(start); | |
} | |
return null; | |
} | |
} |