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386 lines
16 KiB
386 lines
16 KiB
5 years ago
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/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
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*
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* Copyright (c) 1997-2010 Oracle and/or its affiliates. All rights reserved.
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*
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* The contents of this file are subject to the terms of either the GNU
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* General Public License Version 2 only ("GPL") or the Common Development
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* and Distribution License("CDDL") (collectively, the "License"). You
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* may not use this file except in compliance with the License. You can
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* obtain a copy of the License at
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* https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
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* or packager/legal/LICENSE.txt. See the License for the specific
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* language governing permissions and limitations under the License.
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*
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* When distributing the software, include this License Header Notice in each
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* file and include the License file at packager/legal/LICENSE.txt.
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*
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* GPL Classpath Exception:
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* Oracle designates this particular file as subject to the "Classpath"
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* exception as provided by Oracle in the GPL Version 2 section of the License
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* file that accompanied this code.
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*
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* Modifications:
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* If applicable, add the following below the License Header, with the fields
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* enclosed by brackets [] replaced by your own identifying information:
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* "Portions Copyright [year] [name of copyright owner]"
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*
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* Contributor(s):
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* If you wish your version of this file to be governed by only the CDDL or
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* only the GPL Version 2, indicate your decision by adding "[Contributor]
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* elects to include this software in this distribution under the [CDDL or GPL
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* Version 2] license." If you don't indicate a single choice of license, a
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* recipient has the option to distribute your version of this file under
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* either the CDDL, the GPL Version 2 or to extend the choice of license to
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* its licensees as provided above. However, if you add GPL Version 2 code
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* and therefore, elected the GPL Version 2 license, then the option applies
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* only if the new code is made subject to such option by the copyright
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* holder.
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*
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*
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* This file incorporates work covered by the following copyright and
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* permission notice:
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*
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* Copyright 2004 The Apache Software Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* 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 javax.el;
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import java.lang.reflect.Array;
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import java.util.List;
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import java.util.Iterator;
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import java.beans.FeatureDescriptor;
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/**
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* Defines property resolution behavior on arrays.
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*
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* <p>This resolver handles base objects that are Java language arrays.
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* It accepts any object as a property and coerces that object into an
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* integer index into the array. The resulting value is the value in the array
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* at that index.</p>
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*
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* <p>This resolver can be constructed in read-only mode, which means that
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* {@link #isReadOnly} will always return <code>true</code> and
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* {@link #setValue} will always throw
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* <code>PropertyNotWritableException</code>.</p>
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*
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* <p><code>ELResolver</code>s are combined together using
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* {@link CompositeELResolver}s, to define rich semantics for evaluating
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* an expression. See the javadocs for {@link ELResolver} for details.</p>
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*
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* @see CompositeELResolver
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* @see ELResolver
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* @since JSP 2.1
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*/
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public class ArrayELResolver extends ELResolver {
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/**
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* Creates a new read/write <code>ArrayELResolver</code>.
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*/
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public ArrayELResolver() {
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this.isReadOnly = false;
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}
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/**
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* Creates a new <code>ArrayELResolver</code> whose read-only status is
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* determined by the given parameter.
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*
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* @param isReadOnly <code>true</code> if this resolver cannot modify
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* arrays; <code>false</code> otherwise.
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*/
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public ArrayELResolver(boolean isReadOnly) {
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this.isReadOnly = isReadOnly;
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}
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/**
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* If the base object is an array, returns the most general acceptable type
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* for a value in this array.
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*
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* <p>If the base is a <code>array</code>, the
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* <code>propertyResolved</code> property of the <code>ELContext</code>
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* object must be set to <code>true</code> by this resolver, before
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* returning. If this property is not <code>true</code> after this method
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* is called, the caller should ignore the return value.</p>
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*
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* <p>Assuming the base is an <code>array</code>, this method will always
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* return <code>base.getClass().getComponentType()</code>, which is
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* the most general type of component that can be stored at any given
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* index in the array.</p>
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*
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* @param context The context of this evaluation.
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* @param base The array to analyze. Only bases that are Java language
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* arrays are handled by this resolver.
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* @param property The index of the element in the array to return the
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* acceptable type for. Will be coerced into an integer, but
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* otherwise ignored by this resolver.
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* @return If the <code>propertyResolved</code> property of
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* <code>ELContext</code> was set to <code>true</code>, then
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* the most general acceptable type; otherwise undefined.
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* @throws PropertyNotFoundException if the given index is out of
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* bounds for this array.
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* @throws NullPointerException if context is <code>null</code>
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* @throws ELException if an exception was thrown while performing
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* the property or variable resolution. The thrown exception
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* must be included as the cause property of this exception, if
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* available.
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*/
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public Class<?> getType(ELContext context,
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Object base,
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Object property) {
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if (context == null) {
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throw new NullPointerException();
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}
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if (base != null && base.getClass().isArray()) {
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context.setPropertyResolved(true);
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int index = toInteger (property);
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if (index < 0 || index >= Array.getLength(base)) {
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throw new PropertyNotFoundException();
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}
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return base.getClass().getComponentType();
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}
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return null;
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}
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/**
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* If the base object is a Java language array, returns the value at the
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* given index. The index is specified by the <code>property</code>
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* argument, and coerced into an integer. If the coercion could not be
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* performed, an <code>IllegalArgumentException</code> is thrown. If the
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* index is out of bounds, <code>null</code> is returned.
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*
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* <p>If the base is a Java language array, the
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* <code>propertyResolved</code> property of the <code>ELContext</code>
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* object must be set to <code>true</code> by this resolver, before
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* returning. If this property is not <code>true</code> after this
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* method is called, the caller should ignore the return value.</p>
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*
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* @param context The context of this evaluation.
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* @param base The array to analyze. Only bases that are Java language
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* arrays are handled by this resolver.
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* @param property The index of the value to be returned. Will be coerced
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* into an integer.
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* @return If the <code>propertyResolved</code> property of
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* <code>ELContext</code> was set to <code>true</code>, then
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* the value at the given index or <code>null</code>
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* if the index was out of bounds. Otherwise, undefined.
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* @throws IllegalArgumentException if the property could not be coerced
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* into an integer.
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* @throws NullPointerException if context is <code>null</code>.
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* @throws ELException if an exception was thrown while performing
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* the property or variable resolution. The thrown exception
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* must be included as the cause property of this exception, if
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* available.
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*/
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public Object getValue(ELContext context,
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Object base,
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Object property) {
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if (context == null) {
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throw new NullPointerException();
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}
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if (base != null && base.getClass().isArray()) {
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context.setPropertyResolved(base, property);
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int index = toInteger (property);
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if (index >= 0 && index < Array.getLength(base)) {
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return Array.get(base, index);
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}
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}
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return null;
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}
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/**
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* If the base object is a Java language array, attempts to set the
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* value at the given index with the given value. The index is specified
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* by the <code>property</code> argument, and coerced into an integer.
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* If the coercion could not be performed, an
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* <code>IllegalArgumentException</code> is thrown. If the index is
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* out of bounds, a <code>PropertyNotFoundException</code> is thrown.
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*
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* <p>If the base is a Java language array, the
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* <code>propertyResolved</code> property of the <code>ELContext</code>
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* object must be set to <code>true</code> by this resolver, before
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* returning. If this property is not <code>true</code> after this method
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* is called, the caller can safely assume no value was set.</p>
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*
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* <p>If this resolver was constructed in read-only mode, this method will
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* always throw <code>PropertyNotWritableException</code>.</p>
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*
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* @param context The context of this evaluation.
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* @param base The array to be modified. Only bases that are Java language
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* arrays are handled by this resolver.
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* @param property The index of the value to be set. Will be coerced
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* into an integer.
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* @param val The value to be set at the given index.
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* @throws ClassCastException if the class of the specified element
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* prevents it from being added to this array.
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* @throws NullPointerException if context is <code>null</code>.
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* @throws IllegalArgumentException if the property could not be coerced
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* into an integer, or if some aspect of the specified element
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* prevents it from being added to this array.
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* @throws PropertyNotWritableException if this resolver was constructed
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* in read-only mode.
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* @throws PropertyNotFoundException if the given index is out of
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* bounds for this array.
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* @throws ELException if an exception was thrown while performing
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* the property or variable resolution. The thrown exception
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* must be included as the cause property of this exception, if
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* available.
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*/
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public void setValue(ELContext context,
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Object base,
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Object property,
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Object val) {
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if (context == null) {
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throw new NullPointerException();
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}
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if (base != null && base.getClass().isArray()) {
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context.setPropertyResolved(base, property);
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if (isReadOnly) {
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throw new PropertyNotWritableException();
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}
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Class<?> type = base.getClass().getComponentType();
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if (val != null && ! type.isAssignableFrom(val.getClass())) {
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throw new ClassCastException();
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}
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int index = toInteger (property);
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if (index < 0 || index >= Array.getLength(base)) {
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throw new PropertyNotFoundException();
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}
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Array.set(base, index, val);
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}
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}
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/**
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* If the base object is a Java language array, returns whether a call to
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* {@link #setValue} will always fail.
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*
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* <p>If the base is a Java language array, the
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* <code>propertyResolved</code> property of the <code>ELContext</code>
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* object must be set to <code>true</code> by this resolver, before
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* returning. If this property is not <code>true</code> after this method
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* is called, the caller should ignore the return value.</p>
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*
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* <p>If this resolver was constructed in read-only mode, this method will
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* always return <code>true</code>. Otherwise, it returns
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* <code>false</code>.</p>
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*
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* @param context The context of this evaluation.
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* @param base The array to analyze. Only bases that are a Java language
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* array are handled by this resolver.
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* @param property The index of the element in the array to return the
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* acceptable type for. Will be coerced into an integer, but
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* otherwise ignored by this resolver.
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* @return If the <code>propertyResolved</code> property of
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* <code>ELContext</code> was set to <code>true</code>, then
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* <code>true</code> if calling the <code>setValue</code> method
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* will always fail or <code>false</code> if it is possible that
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* such a call may succeed; otherwise undefined.
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* @throws PropertyNotFoundException if the given index is out of
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* bounds for this array.
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* @throws NullPointerException if context is <code>null</code>
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* @throws ELException if an exception was thrown while performing
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* the property or variable resolution. The thrown exception
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* must be included as the cause property of this exception, if
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* available.
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*/
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public boolean isReadOnly(ELContext context,
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Object base,
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Object property) {
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if (context == null) {
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throw new NullPointerException();
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}
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if (base != null && base.getClass().isArray()) {
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context.setPropertyResolved(true);
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int index = toInteger (property);
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if (index < 0 || index >= Array.getLength(base)) {
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throw new PropertyNotFoundException();
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}
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}
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return isReadOnly;
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}
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/**
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* Always returns <code>null</code>, since there is no reason to
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* iterate through set set of all integers.
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*
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* <p>The {@link #getCommonPropertyType} method returns sufficient
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* information about what properties this resolver accepts.</p>
|
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|
*
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* @param context The context of this evaluation.
|
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* @param base The array to analyze. Only bases that are a Java language
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* array are handled by this resolver.
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|
* @return <code>null</code>.
|
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*/
|
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public Iterator<FeatureDescriptor> getFeatureDescriptors(
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ELContext context,
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Object base) {
|
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return null;
|
||
|
}
|
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|
|
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|
/**
|
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* If the base object is a Java language array, returns the most general
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* type that this resolver accepts for the <code>property</code> argument.
|
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|
* Otherwise, returns <code>null</code>.
|
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|
*
|
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|
* <p>Assuming the base is an array, this method will always return
|
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|
* <code>Integer.class</code>. This is because arrays accept integers
|
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|
* for their index.</p>
|
||
|
*
|
||
|
* @param context The context of this evaluation.
|
||
|
* @param base The array to analyze. Only bases that are a Java language
|
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|
* array are handled by this resolver.
|
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|
* @return <code>null</code> if base is not a Java language array;
|
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|
* otherwise <code>Integer.class</code>.
|
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|
*/
|
||
|
public Class<?> getCommonPropertyType(ELContext context,
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Object base) {
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|
if (base != null && base.getClass().isArray()) {
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|
return Integer.class;
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}
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|
return null;
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|
}
|
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|
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|
private int toInteger(Object p) {
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|
|
||
|
if (p instanceof Integer) {
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return ((Integer) p).intValue();
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|
}
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|
if (p instanceof Character) {
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|
return ((Character) p).charValue();
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|
}
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|
if (p instanceof Boolean) {
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return ((Boolean) p).booleanValue()? 1: 0;
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}
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|
if (p instanceof Number) {
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return ((Number) p).intValue();
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}
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|
if (p instanceof String) {
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return Integer.parseInt((String) p);
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}
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throw new IllegalArgumentException();
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|
}
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private boolean isReadOnly;
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}
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