gcc/libjava/javax/swing/text/html/parser/Element.java

/* Element.java --
   Copyright (C) 2005 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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permission to link this library with independent modules to produce an
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package javax.swing.text.html.parser;

import gnu.javax.swing.text.html.parser.support.gnuStringIntMapper;

import java.io.Serializable;

import java.util.BitSet;

/**
 * <p>
 * Stores the element information, obtained by parsing SGML DTD
 * tag <code>&lt;!ELEMENT .. &gt;</code>. This class has no public
 * constructor and can only be instantiated using the
 * {@link javax.swing.text.html.parser.DTD } methods</p>
 *
 * <p>SGML defines elements that represent structures or
 * behavior. An element typically consists of a start tag, content, and an
 * end tag. Hence the elements are not tags. The HTML 4.0 definition specifies
 * that some elements are not required to have the end tags. Also, some
 * HTML elements (like <code>&lt;hr&gt;</code>) have no content. Element names
 * are case sensitive.</p>
 * @author Audrius Meskauskas, Lithuania (AudriusA@Bioinformatics.org)
 */
public final class Element
  implements DTDConstants, Serializable
{
  /**
   * Package level mapper between type names and they string values.
   */
  static final gnuStringIntMapper mapper =
    new gnuStringIntMapper()
    {
      protected void create()
      {
        add("CDATA", DTDConstants.CDATA);
        add("RCDATA", DTDConstants.RCDATA);
        add("EMPTY", DTDConstants.EMPTY);
        add("ANY", DTDConstants.ANY);
      }
    };

  /** Use serialVersionUID for interoperability. */
  private static final long serialVersionUID = -6717939384601675586L;

  /**
   * The element attributes.
   */
  public AttributeList atts;

  /**
   * Contains refernces to elements that must NOT occur inside this element,
   * at any level of hierarchy.
   */
  public BitSet exclusions;

  /**
   * Contains refernces to elements that must CAN occur inside this element,
   * at any level of hierarchy.
   */
  public BitSet inclusions;

  /**
   * The content model, defining elements, entities and DTD text
   * that may/may not occur inside this element.
   */
  public ContentModel content;

  /**
   * A field to store additional user data for this Element.
   */
  public Object data;

  /**
   * The element name.
   */
  public String name;

  /**
   * True is this element need not to have the closing tag, false
   * otherwise. The HTML 4.0 definition specifies
   * that some elements (like <code>&lt;hr&gt;</code>are
   * not required to have the end tags.
   */
  public boolean oEnd;

  /**
   * True is this element need not to have the starting tag, false
   * otherwise. The HTML 4.0 definition specifies
   * that some elements (like <code>&lt;head&gt;</code> or
   * <code>&lt;body&gt;</code>) are
   * not required to have the start tags.

   */
  public boolean oStart;

  /**
   * This field contains the unique integer identifier of this Element,
   * used to refer the element (more exactly, the element flag)
   * in <code>inclusions</code> and <code>exclusions</code> bit set.
   */
  public int index;

  /**
   * The element type, containing value, defined in DTDConstants.
   * In this implementation, the element type can be
   * CDATA, RCDATA, EMPTY or ANY.
   */
  public int type;

  /**
   * The default constructor must have package level access in this
   * class. Use DTD.defineElement(..) to create an element when required.
   * @todo MAKE THIS PACKAGE in the final version. Now the Parser needs it!
   */
  Element()
  {
  }

  /**
   * Converts the string representation of the element type
   * into its unique integer identifier, defined in DTDConstants.
   * @param a_type A name of the type
   * @return DTDConstants.CDATA, DTDConstants.RCDATA, DTDConstants.EMPTY,
   * DTDConstants.ANY or null if the type name is not
   * "CDATA", "RCDATA", "EMPTY" or "ANY". This function is case sensitive.
   * @throws NullPointerException if <code>a_type</code> is null.
   */
  public static int name2type(String a_type)
  {
    return mapper.get(a_type);
  }

  /**
   * Get the element attribute by name.
   * @param attribute the attribute name, case insensitive.
   * @return the correspoding attribute of this element. The class,
   * for storing as attribute list, as a single attribute, is used to
   * store a single attribute in this case.
   * @throws NullPointerException if the attribute name is null.
   */
  public AttributeList getAttribute(String attribute)
  {
    AttributeList a = atts;

    while (a != null && !attribute.equalsIgnoreCase(a.name))
      a = a.next;

    return a;
  }

  /**
   * Get the element attribute by its value.
   * @param a_value the attribute value, case insensitive.
   * @return the correspoding attribute of this element. The class,
   * for storing as attribute list, as a single attribute, is used to
   * store a single attribute in this case. If there are several
   * attributes with the same value, there is no garranty, which one
   * is returned.
   */
  public AttributeList getAttributeByValue(String a_value)
  {
    AttributeList a = atts;

    if (a_value == null)
      {
        while (a != null)
          {
            if (a.value == null)
              return a;

            a = a.next;
          }
      }
    else
      {
        while (a != null)
          {
            if (a.value != null && a_value.equalsIgnoreCase(a.value))
              return a;

            a = a.next;
          }
      }

    return null;
  }

  /**
   * Get all attributes of this document as an attribute list.
   * @return
   */
  public AttributeList getAttributes()
  {
    return atts;
  }

  /**
   * Get the content model, defining elements, entities and DTD text
   * that may/may not occur inside this element.
   */
  public ContentModel getContent()
  {
    return content;
  }

  /**
   * Returns true for the element with no content.
   * Empty elements are defined with the SGML DTD keyword "EMPTY".
   * @return true if content model field (content) method is equal to
   * null or its method empty() returns true.
   */
  public boolean isEmpty()
  {
    return content == null || content.empty();
  }

  /**
   * Get the unique integer identifier of this Element,
   * used to refer the element (more exactly, the element flag)
   * in <code>inclusions</code> and <code>exclusions</code> bit set.
   * WARNING: This value may not be the same between different
   * implementations.
   */
  public int getIndex()
  {
    return index;
  }

  /**
   * Get the element name.
   */
  public String getName()
  {
    return name;
  }

  /**
   * Get the element type.
   * @return one of the values, defined DTDConstants.
   * In this implementation, the element type can be
   * CDATA, RCDATA, EMPTY or ANY.
   */
  public int getType()
  {
    return type;
  }

  /**
   * True is this element need not to have the starting tag, false
   * otherwise.s element need not to have the closing tag, false
   * otherwise. The HTML 4.0 definition specifies
   * that some elements (like <code>&lt;hr&gt;</code>are
   * not required to have the end tags.
   */
  public boolean omitEnd()
  {
    return oEnd;
  }

  /**
   * True is this element need not to have the closing tag, false
   * otherwise. The HTML 4.0 definition specifies
   * that some elements (like <code>&lt;head&gt;</code> or
   * <code>&lt;body&gt;</code>) are
   * not required to have the start tags.
   */
  public boolean omitStart()
  {
    return oStart;
  }

  /**
   * Returns the name of this element.
   */
  public String toString()
  {
    return name;
  }
}