118 lines
4.1 KiB
Java
118 lines
4.1 KiB
Java
/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.apache.el.util;
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import java.security.AccessController;
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import java.security.PrivilegedAction;
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public class Validation {
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// Java keywords, boolean literals & the null literal in alphabetical order
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private static final String invalidIdentifiers[] = { "abstract", "assert",
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"boolean", "break", "byte", "case", "catch", "char", "class", "const",
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"continue", "default", "do", "double", "else", "enum", "extends",
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"false", "final", "finally", "float", "for", "goto", "if", "implements",
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"import", "instanceof", "int", "interface", "long", "native", "new",
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"null", "package", "private", "protected", "public", "return", "short",
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"static", "strictfp", "super", "switch", "synchronized", "this",
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"throw", "throws", "transient", "true", "try", "void", "volatile",
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"while" };
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private static final boolean IS_SECURITY_ENABLED =
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(System.getSecurityManager() != null);
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private static final boolean SKIP_IDENTIFIER_CHECK;
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static {
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String skipIdentifierCheckStr;
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if (IS_SECURITY_ENABLED) {
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skipIdentifierCheckStr = AccessController.doPrivileged(
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new PrivilegedAction<String>(){
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@Override
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public String run() {
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return System.getProperty(
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"org.apache.el.parser.SKIP_IDENTIFIER_CHECK",
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"false");
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}
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}
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);
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} else {
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skipIdentifierCheckStr = System.getProperty(
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"org.apache.el.parser.SKIP_IDENTIFIER_CHECK", "false");
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}
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SKIP_IDENTIFIER_CHECK = Boolean.parseBoolean(skipIdentifierCheckStr);
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}
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private Validation() {
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// Utility class. Hide default constructor
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}
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/**
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* Test whether a string is a Java identifier. Note that the behaviour of
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* this method depend on the system property
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* {@code org.apache.el.parser.SKIP_IDENTIFIER_CHECK}
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*
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* @param key The string to test
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*
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* @return {@code true} if the provided String should be treated as a Java
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* identifier, otherwise false
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*/
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public static boolean isIdentifier(String key) {
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if (SKIP_IDENTIFIER_CHECK) {
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return true;
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}
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// Should not be the case but check to be sure
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if (key == null || key.length() == 0) {
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return false;
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}
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// Check the list of known invalid values
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int i = 0;
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int j = invalidIdentifiers.length;
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while (i < j) {
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int k = (i + j) >>> 1; // Avoid overflow
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int result = invalidIdentifiers[k].compareTo(key);
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if (result == 0) {
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return false;
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}
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if (result < 0) {
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i = k + 1;
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} else {
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j = k;
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}
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}
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// Check the start character that has more restrictions
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if (!Character.isJavaIdentifierStart(key.charAt(0))) {
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return false;
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}
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// Check each remaining character used is permitted
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for (int idx = 1; idx < key.length(); idx++) {
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if (!Character.isJavaIdentifierPart(key.charAt(idx))) {
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return false;
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}
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}
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return true;
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}
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}
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