xobject.java

java1.6众多例子参考

   * @return null
   */
  public int rtf()
  {
    return DTM.NULL;
  }

  /**
   * Return a java object that's closest to the representation
   * that should be handed to an extension.
   *
   * @return The object that this class wraps
   */
  public Object object()
  {
    return m_obj;
  }

  /**
   * Cast result object to a nodelist. Always issues an error.
   *
   * @return null
   *
   * @throws javax.xml.transform.TransformerException
   */
  public DTMIterator iter() throws javax.xml.transform.TransformerException
  {

    error(XPATHErrorResources.ER_CANT_CONVERT_TO_NODELIST,
          new Object[]{ getTypeString() });  //"Can not convert "+getTypeString()+" to a NodeList!");

    return null;
  }
  
  /**
   * Get a fresh copy of the object.  For use with variables.
   *
   * @return This object, unless overridden by subclass.
   */
  public XObject getFresh()
  {
    return this;
  }

  
  /**
   * Cast result object to a nodelist. Always issues an error.
   *
   * @return null
   *
   * @throws javax.xml.transform.TransformerException
   */
  public NodeIterator nodeset() throws javax.xml.transform.TransformerException
  {

    error(XPATHErrorResources.ER_CANT_CONVERT_TO_NODELIST,
          new Object[]{ getTypeString() });  //"Can not convert "+getTypeString()+" to a NodeList!");

    return null;
  }
  
  /**
   * Cast result object to a nodelist. Always issues an error.
   *
   * @return null
   *
   * @throws javax.xml.transform.TransformerException
   */
  public NodeList nodelist() throws javax.xml.transform.TransformerException
  {

    error(XPATHErrorResources.ER_CANT_CONVERT_TO_NODELIST,
          new Object[]{ getTypeString() });  //"Can not convert "+getTypeString()+" to a NodeList!");

    return null;
  }


  /**
   * Cast result object to a nodelist. Always issues an error.
   *
   * @return The object as a NodeSetDTM.
   *
   * @throws javax.xml.transform.TransformerException
   */
  public NodeSetDTM mutableNodeset()
          throws javax.xml.transform.TransformerException
  {

    error(XPATHErrorResources.ER_CANT_CONVERT_TO_MUTABLENODELIST,
          new Object[]{ getTypeString() });  //"Can not convert "+getTypeString()+" to a NodeSetDTM!");

    return (NodeSetDTM) m_obj;
  }

  /**
   * Cast object to type t.
   *
   * @param t Type of object to cast this to
   * @param support XPath context to use for the conversion
   *
   * @return This object as the given type t
   *
   * @throws javax.xml.transform.TransformerException
   */
  public Object castToType(int t, XPathContext support)
          throws javax.xml.transform.TransformerException
  {

    Object result;

    switch (t)
    {
    case CLASS_STRING :
      result = str();
      break;
    case CLASS_NUMBER :
      result = new Double(num());
      break;
    case CLASS_NODESET :
      result = iter();
      break;
    case CLASS_BOOLEAN :
      result = new Boolean(bool());
      break;
    case CLASS_UNKNOWN :
      result = m_obj;
      break;

    // %TBD%  What to do here?
    //    case CLASS_RTREEFRAG :
    //      result = rtree(support);
    //      break;
    default :
      error(XPATHErrorResources.ER_CANT_CONVERT_TO_TYPE,
            new Object[]{ getTypeString(),
                          Integer.toString(t) });  //"Can not convert "+getTypeString()+" to a type#"+t);

      result = null;
    }

    return result;
  }

  /**
   * Tell if one object is less than the other.
   *
   * @param obj2 Object to compare this to
   *
   * @return True if this object is less than the given object
   *
   * @throws javax.xml.transform.TransformerException
   */
  public boolean lessThan(XObject obj2)
          throws javax.xml.transform.TransformerException
  {

    // In order to handle the 'all' semantics of 
    // nodeset comparisons, we always call the 
    // nodeset function.  Because the arguments 
    // are backwards, we call the opposite comparison
    // function.
    if (obj2.getType() == XObject.CLASS_NODESET)
      return obj2.greaterThan(this);

    return this.num() < obj2.num();
  }

  /**
   * Tell if one object is less than or equal to the other.
   *
   * @param obj2 Object to compare this to
   *
   * @return True if this object is less than or equal to the given object
   *
   * @throws javax.xml.transform.TransformerException
   */
  public boolean lessThanOrEqual(XObject obj2)
          throws javax.xml.transform.TransformerException
  {

    // In order to handle the 'all' semantics of 
    // nodeset comparisons, we always call the 
    // nodeset function.  Because the arguments 
    // are backwards, we call the opposite comparison
    // function.
    if (obj2.getType() == XObject.CLASS_NODESET)
      return obj2.greaterThanOrEqual(this);

    return this.num() <= obj2.num();
  }

  /**
   * Tell if one object is greater than the other.
   *
   * @param obj2 Object to compare this to
   *
   * @return True if this object is greater than the given object
   *
   * @throws javax.xml.transform.TransformerException
   */
  public boolean greaterThan(XObject obj2)
          throws javax.xml.transform.TransformerException
  {

    // In order to handle the 'all' semantics of 
    // nodeset comparisons, we always call the 
    // nodeset function.  Because the arguments 
    // are backwards, we call the opposite comparison
    // function.
    if (obj2.getType() == XObject.CLASS_NODESET)
      return obj2.lessThan(this);

    return this.num() > obj2.num();
  }

  /**
   * Tell if one object is greater than or equal to the other.
   *
   * @param obj2 Object to compare this to
   *
   * @return True if this object is greater than or equal to the given object
   *
   * @throws javax.xml.transform.TransformerException
   */
  public boolean greaterThanOrEqual(XObject obj2)
          throws javax.xml.transform.TransformerException
  {

    // In order to handle the 'all' semantics of 
    // nodeset comparisons, we always call the 
    // nodeset function.  Because the arguments 
    // are backwards, we call the opposite comparison
    // function.
    if (obj2.getType() == XObject.CLASS_NODESET)
      return obj2.lessThanOrEqual(this);

    return this.num() >= obj2.num();
  }

  /**
   * Tell if two objects are functionally equal.
   *
   * @param obj2 Object to compare this to
   *
   * @return True if this object is equal to the given object
   *
   * @throws javax.xml.transform.TransformerException
   */
  public boolean equals(XObject obj2)
  {

    // In order to handle the 'all' semantics of 
    // nodeset comparisons, we always call the 
    // nodeset function.
    if (obj2.getType() == XObject.CLASS_NODESET)
      return obj2.equals(this);

    if (null != m_obj)
    {
      return m_obj.equals(obj2.m_obj);
    }
    else
    {
      return obj2.m_obj == null;
    }
  }

  /**
   * Tell if two objects are functionally not equal.
   *
   * @param obj2 Object to compare this to
   *
   * @return True if this object is not equal to the given object
   *
   * @throws javax.xml.transform.TransformerException
   */
  public boolean notEquals(XObject obj2)
          throws javax.xml.transform.TransformerException
  {

    // In order to handle the 'all' semantics of 
    // nodeset comparisons, we always call the 
    // nodeset function.
    if (obj2.getType() == XObject.CLASS_NODESET)
      return obj2.notEquals(this);

    return !equals(obj2);
  }

  /**
   * Tell the user of an error, and probably throw an
   * exception.
   *
   * @param msg Error message to issue
   *
   * @throws javax.xml.transform.TransformerException
   */
  protected void error(String msg)
          throws javax.xml.transform.TransformerException
  {
    error(msg, null);
  }

  /**
   * Tell the user of an error, and probably throw an
   * exception.
   *
   * @param msg Error message to issue
   * @param args Arguments to use in the message
   *
   * @throws javax.xml.transform.TransformerException
   */
  protected void error(String msg, Object[] args)
          throws javax.xml.transform.TransformerException
  {

    String fmsg = XSLMessages.createXPATHMessage(msg, args);

    // boolean shouldThrow = support.problem(m_support.XPATHPROCESSOR, 
    //                                      m_support.ERROR,
    //                                      null, 
    //                                      null, fmsg, 0, 0);
    // if(shouldThrow)
    {
      throw new XPathException(fmsg, this);
    }
  }
  
  
  /**
   * XObjects should not normally need to fix up variables.
   */
  public void fixupVariables(java.util.Vector vars, int globalsSize)
  {
    // no-op
  }


  /**
   * Cast result object to a string.
   *
   *
   * NEEDSDOC @param fsb
   * @return The string this wraps or the empty string if null
   */
  public void appendToFsb(com.sun.org.apache.xml.internal.utils.FastStringBuffer fsb)
  {
    fsb.append(str());
  }
  
  /**
   * @see com.sun.org.apache.xpath.internal.XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor)
   */
  public void callVisitors(ExpressionOwner owner, XPathVisitor visitor)
  {
  	assertion(false, "callVisitors should not be called for this object!!!");
  }
  /**
   * @see Expression#deepEquals(Expression)
   */
  public boolean deepEquals(Expression expr)
  {
  	if(!isSameClass(expr))
  		return false;
  		
  	// If equals at the expression level calls deepEquals, I think we're 
  	// still safe from infinite recursion since this object overrides 
  	// equals.  I hope.
  	if(!this.equals((XObject)expr))
  		return false;
  		
  	return true;
  }

}