Java tutorial
/* * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. * * Copyright (c) 1997-2010 Oracle and/or its affiliates. All rights reserved. * * The contents of this file are subject to the terms of either the GNU * General Public License Version 2 only ("GPL") or the Common Development * and Distribution License("CDDL") (collectively, the "License"). You * may not use this file except in compliance with the License. You can * obtain a copy of the License at * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html * or packager/legal/LICENSE.txt. See the License for the specific * language governing permissions and limitations under the License. * * When distributing the software, include this License Header Notice in each * file and include the License file at packager/legal/LICENSE.txt. * * GPL Classpath Exception: * Oracle designates this particular file as subject to the "Classpath" * exception as provided by Oracle in the GPL Version 2 section of the License * file that accompanied this code. * * Modifications: * If applicable, add the following below the License Header, with the fields * enclosed by brackets [] replaced by your own identifying information: * "Portions Copyright [year] [name of copyright owner]" * * Contributor(s): * If you wish your version of this file to be governed by only the CDDL or * only the GPL Version 2, indicate your decision by adding "[Contributor] * elects to include this software in this distribution under the [CDDL or GPL * Version 2] license." If you don't indicate a single choice of license, a * recipient has the option to distribute your version of this file under * either the CDDL, the GPL Version 2 or to extend the choice of license to * its licensees as provided above. However, if you add GPL Version 2 code * and therefore, elected the GPL Version 2 license, then the option applies * only if the new code is made subject to such option by the copyright * holder. * * * This file incorporates work covered by the following copyright and * permission notice: * * Copyright 2004 The Apache Software Foundation * * Licensed 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 javax.servlet.jsp.tagext; import java.util.Hashtable; /** * The (translation-time only) attribute/value information for a tag instance. * * <p> * TagData is only used as an argument to the isValid, validate, and * getVariableInfo methods of TagExtraInfo, which are invoked at * translation time. */ public class TagData implements Cloneable { /** * Distinguished value for an attribute to indicate its value * is a request-time expression (which is not yet available because * TagData instances are used at translation-time). */ public static final Object REQUEST_TIME_VALUE = new Object(); /** * Constructor for TagData. * * <p> * A typical constructor may be * <pre> * static final Object[][] att = {{"connection", "conn0"}, {"id", "query0"}}; * static final TagData td = new TagData(att); * </pre> * * All values must be Strings except for those holding the * distinguished object REQUEST_TIME_VALUE. * @param atts the static attribute and values. May be null. */ public TagData(Object[] atts[]) { if (atts == null) { attributes = new Hashtable<String, Object>(); } else { attributes = new Hashtable<String, Object>(atts.length); } if (atts != null) { for (int i = 0; i < atts.length; i++) { attributes.put((String) atts[i][0], atts[i][1]); } } } /** * Constructor for a TagData. * * If you already have the attributes in a hashtable, use this * constructor. * * @param attrs A hashtable to get the values from. */ public TagData(Hashtable<String, Object> attrs) { this.attributes = attrs; } /** * The value of the tag's id attribute. * * @return the value of the tag's id attribute, or null if no such * attribute was specified. */ public String getId() { return getAttributeString(TagAttributeInfo.ID); } /** * The value of the attribute. * If a static value is specified for an attribute that accepts a * request-time attribute expression then that static value is returned, * even if the value is provided in the body of a <jsp:attribute> action. * The distinguished object REQUEST_TIME_VALUE is only returned if * the value is specified as a request-time attribute expression * or via the <jsp:attribute> action with a body that contains * dynamic content (scriptlets, scripting expressions, EL expressions, * standard actions, or custom actions). Returns null if the attribute * is not set. * * @param attName the name of the attribute * @return the attribute's value */ public Object getAttribute(String attName) { return attributes.get(attName); } /** * Set the value of an attribute. * * @param attName the name of the attribute * @param value the value. */ public void setAttribute(String attName, Object value) { attributes.put(attName, value); } /** * Get the value for a given attribute. * * @param attName the name of the attribute * @return the attribute value string * @throws ClassCastException if attribute value is not a String */ public String getAttributeString(String attName) { Object o = attributes.get(attName); if (o == null) { return null; } else { return (String) o; } } /** * Enumerates the attributes. * *@return An enumeration of the attributes in a TagData */ public java.util.Enumeration<String> getAttributes() { return attributes.keys(); }; // private data private Hashtable<String, Object> attributes; // the tagname/value map }