public ContentModel() 
{

}

 public ContentModel(Element content) 
{
        this(0, content, null);
}

Create a content model for an element.

 public ContentModel(int type,
    ContentModel content) 
{
        this(type, content, null);
}

Create a content model of a particular type.

 public ContentModel(int type,
    Object content,
    ContentModel next) 
{
        this.type = type;
        this.content = content;
        this.next = next;
}

Create a content model of a particular type.

 public boolean empty() 
{
        switch (type) {
          case '*":
          case '?":
            return true;
          case '+":
          case '|":
            for (ContentModel m = (ContentModel)content ; m != null ; m = m.next) {
                if (m.empty()) {
                    return true;
                }
            }
            return false;
          case ',":
          case '&":
            for (ContentModel m = (ContentModel)content ; m != null ; m = m.next) {
                if (!m.empty()) {
                    return false;
                }
            }
            return true;
          default:
            return false;
        }
}

Return true if the content model could match an empty input stream.

 public Element first() 
{
        switch (type) {
          case '&":
          case '|":
          case '*":
          case '?":
            return null;
          case '+":
          case ',":
            return ((ContentModel)content).first();
          default:
            return (Element)content;
        }
}

Return the element that must be next.

 public boolean first(Object token) 
{
        switch (type) {
          case '*":
          case '?":
          case '+":
            return ((ContentModel)content).first(token);
          case ',":
            for (ContentModel m = (ContentModel)content ; m != null ; m = m.next) {
                if (m.first(token)) {
                    return true;
                }
                if (!m.empty()) {
                    return false;
                }
            }
            return false;
          case '|":
          case '&": {
            Element e = (Element) token;
            if (valSet == null) {
                valSet = new boolean[Element.maxIndex + 1];
                val = new boolean[Element.maxIndex + 1];
                // All Element instances are created before this ever executes
            }
            if (valSet[e.index]) {
                return val[e.index];
            }
            for (ContentModel m = (ContentModel)content ; m != null ; m = m.next) {
                if (m.first(token)) {
                    val[e.index] = true;
                    break;
                }
            }
            valSet[e.index] = true;
            return val[e.index];
          }
          default:
            return (content == token);
            // PENDING: refer to comment in ContentModelState
/*
              if (content == token) {
                  return true;
              }
              Element e = (Element)content;
              if (e.omitStart() && e.content != null) {
                  return e.content.first(token);
              }
              return false;
*/
        }
}

Return true if the token could potentially be the first token in the input stream.

 public  void getElements(Vector elemVec) 
{
         switch (type) {
         case '*":
         case '?":
         case '+":
             ((ContentModel)content).getElements(elemVec);
             break;
         case ',":
         case '|":
         case '&":
             for (ContentModel m=(ContentModel)content; m != null; m=m.next){
                 m.getElements(elemVec);
             }
             break;
         default:
             elemVec.addElement((Element)content);
         }
}

Update elemVec with the list of elements that are part of the this contentModel.

 public String toString() 
{
        switch (type) {
          case '*":
            return content + "*";
          case '?":
            return content + "?";
          case '+":
            return content + "+";
          case ',":
          case '|":
          case '&":
            char data[] = {' ", (char)type, ' "};
            String str = "";
            for (ContentModel m = (ContentModel)content ; m != null ; m = m.next) {
                str = str + m;
                if (m.next != null) {
                    str += new String(data);
                }
            }
            return "(" + str + ")";
          default:
            return content.toString();
        }
}

Convert to a string.