| /* |
| * 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.el.util; |
| |
| import java.security.AccessController; |
| import java.security.PrivilegedAction; |
| |
| public class Validation { |
| |
| // Java keywords, boolean literals & the null literal in alphabetical order |
| private static final String invalidIdentifiers[] = { "abstract", "assert", |
| "boolean", "break", "byte", "case", "catch", "char", "class", "const", |
| "continue", "default", "do", "double", "else", "enum", "extends", |
| "false", "final", "finally", "float", "for", "goto", "if", "implements", |
| "import", "instanceof", "int", "interface", "long", "native", "new", |
| "null", "package", "private", "protected", "public", "return", "short", |
| "static", "strictfp", "super", "switch", "synchronized", "this", |
| "throw", "throws", "transient", "true", "try", "void", "volatile", |
| "while" }; |
| |
| private static final boolean IS_SECURITY_ENABLED = |
| (System.getSecurityManager() != null); |
| |
| private static final boolean SKIP_IDENTIFIER_CHECK; |
| |
| static { |
| if (IS_SECURITY_ENABLED) { |
| SKIP_IDENTIFIER_CHECK = AccessController.doPrivileged( |
| new PrivilegedAction<Boolean>(){ |
| @Override |
| public Boolean run() { |
| return Boolean.valueOf(System.getProperty( |
| "org.apache.el.parser.SKIP_IDENTIFIER_CHECK", |
| "false")); |
| } |
| } |
| ).booleanValue(); |
| } else { |
| SKIP_IDENTIFIER_CHECK = Boolean.valueOf(System.getProperty( |
| "org.apache.el.parser.SKIP_IDENTIFIER_CHECK", |
| "false")).booleanValue(); |
| } |
| } |
| |
| |
| private Validation() { |
| // Utility class. Hide default constructor |
| } |
| |
| /** |
| * Test whether the argument is a Java identifier. |
| */ |
| public static boolean isIdentifier(String key) { |
| |
| if (SKIP_IDENTIFIER_CHECK) { |
| return true; |
| } |
| |
| // Should not be the case but check to be sure |
| if (key == null || key.length() == 0) { |
| return false; |
| } |
| |
| // Check the list of known invalid values |
| int i = 0; |
| int j = invalidIdentifiers.length; |
| while (i < j) { |
| int k = (i + j) >>> 1; // Avoid overflow |
| int result = invalidIdentifiers[k].compareTo(key); |
| if (result == 0) { |
| return false; |
| } |
| if (result < 0) { |
| i = k + 1; |
| } else { |
| j = k; |
| } |
| } |
| |
| // Check the start character that has more restrictions |
| if (!Character.isJavaIdentifierStart(key.charAt(0))) { |
| return false; |
| } |
| |
| // Check each remaining character used is permitted |
| for (int idx = 1; idx < key.length(); idx++) { |
| if (!Character.isJavaIdentifierPart(key.charAt(idx))) { |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| } |