// HTMLParser Library $Name: v1_6_20060319 $ - A java-based parser for HTML// http://sourceforge.org/projects/htmlparser// Copyright (C) 2004 Derrick Oswald//// Revision Control Information//// $Source: /cvsroot/htmlparser/htmlparser/src/org/htmlparser/Attribute.java,v $// $Author: derrickoswald $// $Date: 2005/11/15 02:09:10 $// $Revision: 1.8 $//// This library is free software; you can redistribute it and/or// modify it under the terms of the GNU Lesser General Public// License as published by the Free Software Foundation; either// version 2.1 of the License, or (at your option) any later version.//// This library is distributed in the hope that it will be useful,// but WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU// Lesser General Public License for more details.//// You should have received a copy of the GNU Lesser General Public// License along with this library; if not, write to the Free Software// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA//package org.htmlparser;import java.io.Serializable;/** * An attribute within a tag. * Holds the name, assignment string, value and quote character. * <p> * This class was made deliberately simple. Except for * {@link #setRawValue RawValue}, the properties are completely orthogonal, * that is: each property is independant of the others. This means you have * enough rope here to hang yourself, and it's very easy to create * malformed HTML. Where it's obvious, warnings and notes have been provided * in the setters javadocs, but it is up to you -- the programmer -- * to ensure that the contents of the four fields will yield valid HTML * (if that's what you want). * <p> * Be especially mindful of quotes and assignment strings. These are handled * by the constructors where it's obvious, but in general, you need to set * them explicitly when building an attribute. For example to construct * the attribute <b><code>label="A multi word value."</code></b> you could use: * <pre> *     attribute = new Attribute (); *     attribute.setName ("label"); *     attribute.setAssignment ("="); *     attribute.setValue ("A multi word value."); *     attribute.setQuote ('"'); * </pre> * or * <pre> *     attribute = new Attribute (); *     attribute.setName ("label"); *     attribute.setAssignment ("="); *     attribute.setRawValue ("A multi word value."); * </pre> * or * <pre> *     attribute = new Attribute ("label", "A multi word value."); * </pre> * Note that the assignment value and quoting need to be set separately when * building the attribute from scratch using the properties. * <p> * <table width="100.0%" align="Center" border="1"> *   <caption>Valid States for Attributes.</caption> *   <tr> *     <th align="Center">Description</th> *     <th align="Center">toString()</th> *     <th align="Center">Name</th> *     <th align="Center">Assignment</th> *     <th align="Center">Value</th> *     <th align="Center">Quote</th> *   </tr> *   <tr> *     <td align="Center">whitespace attribute</td> *     <td align="Center">value</td> *     <td align="Center"><code>null</code></td> *     <td align="Center"><code>null</code></td> *     <td align="Center">"value"</td> *     <td align="Center"><code>0</code></td> *   </tr> *   <tr> *     <td align="Center">standalone attribute</td> *     <td align="Center">name</td> *     <td align="Center">"name"</td> *     <td align="Center"><code>null</code></td> *     <td align="Center"><code>null</code></td> *     <td align="Center"><code>0</code></td> *   </tr> *   <tr> *     <td align="Center">empty attribute</td> *     <td align="Center">name=</td> *     <td align="Center">"name"</td> *     <td align="Center">"="</td> *     <td align="Center"><code>null</code></td> *     <td align="Center"><code>0</code></td> *   </tr> *   <tr> *     <td align="Center">empty single quoted attribute</td> *     <td align="Center">name=''</td> *     <td align="Center">"name"</td> *     <td align="Center">"="</td> *     <td align="Center"><code>null</code></td> *     <td align="Center"><code>'</code></td> *   </tr> *   <tr> *     <td align="Center">empty double quoted attribute</td> *     <td align="Center">name=""</td> *     <td align="Center">"name"</td> *     <td align="Center">"="</td> *     <td align="Center"><code>null</code></td> *     <td align="Center"><code>"</code></td> *   </tr> *   <tr> *     <td align="Center">naked attribute</td> *     <td align="Center">name=value</td> *     <td align="Center">"name"</td> *     <td align="Center">"="</td> *     <td align="Center">"value"</td> *     <td align="Center"><code>0</code></td> *   </tr> *   <tr> *     <td align="Center">single quoted attribute</td> *     <td align="Center">name='value'</td> *     <td align="Center">"name"</td> *     <td align="Center">"="</td> *     <td align="Center">"value"</td> *     <td align="Center"><code>'</code></td> *   </tr> *   <tr> *     <td align="Center">double quoted attribute</td> *     <td align="Center">name="value"</td> *     <td align="Center">"name"</td> *     <td align="Center">"="</td> *     <td align="Center">"value"</td> *     <td align="Center"><code>"</code></td> *   </tr> * </table> * <br>In words: * <br>If Name is null, and Assignment is null, and Quote is zero, *   it's whitepace and Value has the whitespace text -- value * <br>If Name is not null, and both Assignment and Value are null *   it's a standalone attribute -- name * <br>If Name is not null, and Assignment is an equals sign, and Quote is zero *   it's an empty attribute -- name= * <br>If Name is not null, and Assignment is an equals sign, *   and Value is "" or null, and Quote is ' *   it's an empty single quoted attribute -- name='' * <br>If Name is not null, and Assignment is an equals sign, *   and Value is "" or null, and Quote is " *   it's an empty double quoted attribute -- name="" * <br>If Name is not null, and Assignment is an equals sign, *   and Value is something, and Quote is zero *   it's a naked attribute -- name=value * <br>If Name is not null, and Assignment is an equals sign, *   and Value is something, and Quote is ' *   it's a single quoted attribute -- name='value' * <br>If Name is not null, and Assignment is an equals sign, *   and Value is something, and Quote is " *   it's a double quoted attribute -- name="value" * <br>All other states are invalid HTML. * <p> * From the <a href="http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2"> * HTML 4.01 Specification, W3C Recommendation 24 December 1999</a> * http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2:<p> * <cite> * 3.2.2 Attributes<p> * Elements may have associated properties, called attributes, which may * have values (by default, or set by authors or scripts). Attribute/value * pairs appear before the final ">" of an element's start tag. Any number * of (legal) attribute value pairs, separated by spaces, may appear in an * element's start tag. They may appear in any order.<p> * In this example, the id attribute is set for an H1 element: * <pre> * <code> * {@.html *  <H1 id="section1"> *  This is an identified heading thanks to the id attribute *  </H1>} * </code> * </pre> * By default, SGML requires that all attribute values be delimited using * either double quotation marks (ASCII decimal 34) or single quotation * marks (ASCII decimal 39). Single quote marks can be included within the * attribute value when the value is delimited by double quote marks, and * vice versa. Authors may also use numeric character references to * represent double quotes (&amp;#34;) and single quotes (&amp;#39;). * For doublequotes authors can also use the character entity reference * &amp;quot;.<p> * In certain cases, authors may specify the value of an attribute without * any quotation marks. The attribute value may only contain letters * (a-z and A-Z), digits (0-9), hyphens (ASCII decimal 45), * periods (ASCII decimal 46), underscores (ASCII decimal 95), * and colons (ASCII decimal 58). We recommend using quotation marks even * when it is possible to eliminate them.<p> * Attribute names are always case-insensitive.<p> * Attribute values are generally case-insensitive. The definition of each * attribute in the reference manual indicates whether its value is * case-insensitive.<p> * All the attributes defined by this specification are listed in the * <a href="http://www.w3.org/TR/html4/index/attributes.html">attribute * index</a>.<p> * </cite> * <p> */public class Attribute    implements        Serializable{    /**     * The name of this attribute.     * The part before the equals sign, or the stand-alone attribute.     * This will be <code>null</code> if the attribute is whitespace.     */    protected String mName;    /**     * The assignment string of the attribute.     * The equals sign.     * This will be <code>null</code> if the attribute is a     * stand-alone attribute.     */    protected String mAssignment;    /**     * The value of the attribute.     * The part after the equals sign.     * This will be <code>null</code> if the attribute is an empty or     * stand-alone attribute.     */    protected String mValue;    /**     * The quote, if any, surrounding the value of the attribute, if any.     * This will be zero if there are no quotes around the value.     */    protected char mQuote;    /**     * Create an attribute with the name, assignment, value and quote given.     * If the quote value is zero, assigns the value using {@link #setRawValue}     * which sets the quote character to a proper value if necessary.     * @param name The name of this attribute.     * @param assignment The assignment string of this attribute.     * @param value The value of this attribute.     * @param quote The quote around the value of this attribute.     */    public Attribute (String name, String assignment, String value, char quote)    {        setName (name);        setAssignment (assignment);        if (0 == quote)            setRawValue (value);        else        {            setValue (value);            setQuote (quote);        }    }    /**     * Create an attribute with the name, value and quote given.     * Uses an equals sign as the assignment string if the value is not     * <code>null</code>, and calls {@link #setRawValue} to get the     * correct quoting if <code>quote</code> is zero.     * @param name The name of this attribute.     * @param value The value of this attribute.     * @param quote The quote around the value of this attribute.     */    public Attribute (String name, String value, char quote)    {        this (name, (null == value ? "" : "="), value, quote);    }    /**     * Create a whitespace attribute with the value given.     * @param value The value of this attribute.     * @exception IllegalArgumentException if the value contains other than     * whitespace. To set a real value use {@link #Attribute(String,String)}.     */    public Attribute (String value)        throws            IllegalArgumentException    {        if (0 != value.trim ().length ())            throw new IllegalArgumentException ("non whitespace value");        else        {            setName (null);            setAssignment (null);            setValue (value);            setQuote ((char)0);        }    }    /**     * Create an attribute with the name and value given.     * Uses an equals sign as the assignment string if the value is not     * <code>null</code>, and calls {@link #setRawValue} to get the     * correct quoting.     * @param name The name of this attribute.     * @param value The value of this attribute.     */    public Attribute (String name, String value)    {        this (name, (null == value ? "" : "="), value, (char)0);    }    /**     * Create an attribute with the name, assignment string and value given.     * Calls {@link #setRawValue} to get the correct quoting.     * @param name The name of this attribute.     * @param assignment The assignment string of this attribute.     * @param value The value of this attribute.     */    public Attribute (String name, String assignment, String value)    {        this (name, assignment, value, (char)0);    }    /**     * Create an empty attribute.     * This will provide "" from the {@link #toString} and     * {@link #toString(StringBuffer)} methods.     */    public Attribute ()    {        this (null, null, null, (char)0);    }    /**     * Get the name of this attribute.     * The part before the equals sign, or the contents of the     * stand-alone attribute.     * @return The name, or <code>null</code> if it's just a whitepace     * 'attribute'.     * @see #setName     */    public String getName ()    {        return (mName);    }    /**     * Get the name of this attribute.     * @param buffer The buffer to place the name in.     * @see #getName()     * @see #setName     */    public void getName (StringBuffer buffer)    {        if (null != mName)            buffer.append (mName);    }    /**     * Set the name of this attribute.     * Set the part before the equals sign, or the contents of the     * stand-alone attribute.     * <em>WARNING:</em> Setting this to <code>null</code> can result in     * malformed HTML if the assignment string is not <code>null</code>.     * @param name The new name.     * @see #getName     * @see #getName(StringBuffer)     */    public void setName (String name)    {        mName = name;    }    /**     * Get the assignment string of this attribute.