Module java.desktop

Class HTMLDocument.HTMLReader

  • Enclosing class:

    public class HTMLDocument.HTMLReader
    extends HTMLEditorKit.ParserCallback
    An HTML reader to load an HTML document with an HTML element structure. This is a set of callbacks from the parser, implemented to create a set of elements tagged with attributes. The parse builds up tokens (ElementSpec) that describe the element subtree desired, and burst it into the document under the protection of a write lock using the insert method on the document outer class.

    The reader can be configured by registering actions (of type HTMLDocument.HTMLReader.TagAction) that describe how to handle the action. The idea behind the actions provided is that the most natural text editing operations can be provided if the element structure boils down to paragraphs with runs of some kind of style in them. Some things are more naturally specified structurally, so arbitrary structure should be allowed above the paragraphs, but will need to be edited with structural actions. The implication of this is that some of the HTML elements specified in the stream being parsed will be collapsed into attributes, and in some cases paragraphs will be synthesized. When HTML elements have been converted to attributes, the attribute key will be of type HTML.Tag, and the value will be of type AttributeSet so that no information is lost. This enables many of the existing actions to work so that the user can type input, hit the return key, backspace, delete, etc and have a reasonable result. Selections can be created, and attributes applied or removed, etc. With this in mind, the work done by the reader can be categorized into the following kinds of tasks:

    Build the structure like it's specified in the stream. This produces elements that contain other elements.
    Like block except that it's expected that the element will be used with a paragraph view so a paragraph element won't need to be synthesized.
    Contribute the element as an attribute that will start and stop at arbitrary text locations. This will ultimately be mixed into a run of text, with all of the currently flattened HTML character elements.
    Produce an embedded graphical element.
    Produce an element that is like the embedded graphical element, except that it also has a component model associated with it.
    Create an element that is hidden from view when the document is being viewed read-only, and visible when the document is being edited. This is useful to keep the model from losing information, and used to store things like comments and unrecognized tags.

    Currently, <APPLET>, <PARAM>, <MAP>, <AREA>, <LINK>, <SCRIPT> and <STYLE> are unsupported.

    The assignment of the actions described is shown in the following table for the tags defined in HTML.Tag.

    HTML tags and assigned actions
    Tag Action
    HTML.Tag.A CharacterAction
    HTML.Tag.ADDRESS CharacterAction
    HTML.Tag.APPLET HiddenAction
    HTML.Tag.AREA AreaAction
    HTML.Tag.B CharacterAction
    HTML.Tag.BASE BaseAction
    HTML.Tag.BASEFONT CharacterAction
    HTML.Tag.BIG CharacterAction
    HTML.Tag.BLOCKQUOTE BlockAction
    HTML.Tag.BODY BlockAction
    HTML.Tag.BR SpecialAction
    HTML.Tag.CAPTION BlockAction
    HTML.Tag.CENTER BlockAction
    HTML.Tag.CITE CharacterAction
    HTML.Tag.CODE CharacterAction
    HTML.Tag.DD BlockAction
    HTML.Tag.DFN CharacterAction
    HTML.Tag.DIR BlockAction
    HTML.Tag.DIV BlockAction
    HTML.Tag.DL BlockAction
    HTML.Tag.DT ParagraphAction
    HTML.Tag.EM CharacterAction
    HTML.Tag.FONT CharacterAction
    HTML.Tag.FORM As of 1.4 a BlockAction
    HTML.Tag.FRAME SpecialAction
    HTML.Tag.FRAMESET BlockAction
    HTML.Tag.H1 ParagraphAction
    HTML.Tag.H2 ParagraphAction
    HTML.Tag.H3 ParagraphAction
    HTML.Tag.H4 ParagraphAction
    HTML.Tag.H5 ParagraphAction
    HTML.Tag.H6 ParagraphAction
    HTML.Tag.HEAD HeadAction
    HTML.Tag.HR SpecialAction
    HTML.Tag.HTML BlockAction
    HTML.Tag.I CharacterAction
    HTML.Tag.IMG SpecialAction
    HTML.Tag.INPUT FormAction
    HTML.Tag.ISINDEX IsndexAction
    HTML.Tag.KBD CharacterAction
    HTML.Tag.LI BlockAction
    HTML.Tag.LINK LinkAction
    HTML.Tag.MAP MapAction
    HTML.Tag.MENU BlockAction
    HTML.Tag.META MetaAction
    HTML.Tag.NOFRAMES BlockAction
    HTML.Tag.OBJECT SpecialAction
    HTML.Tag.OL BlockAction
    HTML.Tag.OPTION FormAction
    HTML.Tag.P ParagraphAction
    HTML.Tag.PARAM HiddenAction
    HTML.Tag.PRE PreAction
    HTML.Tag.SAMP CharacterAction
    HTML.Tag.SCRIPT HiddenAction
    HTML.Tag.SELECT FormAction
    HTML.Tag.SMALL CharacterAction
    HTML.Tag.STRIKE CharacterAction
    HTML.Tag.S CharacterAction
    HTML.Tag.STRONG CharacterAction
    HTML.Tag.STYLE StyleAction
    HTML.Tag.SUB CharacterAction
    HTML.Tag.SUP CharacterAction
    HTML.Tag.TABLE BlockAction
    HTML.Tag.TD BlockAction
    HTML.Tag.TEXTAREA FormAction
    HTML.Tag.TH BlockAction
    HTML.Tag.TITLE TitleAction
    HTML.Tag.TR BlockAction
    HTML.Tag.TT CharacterAction
    HTML.Tag.U CharacterAction
    HTML.Tag.UL BlockAction
    HTML.Tag.VAR CharacterAction

    Once </html> is encountered, the Actions are no longer notified.

    • Constructor Detail

      • HTMLReader

        public HTMLReader​(int offset)
        Constructs an HTMLReader using default pop and push depth and no tag to insert.
        offset - the starting offset
      • HTMLReader

        public HTMLReader​(int offset,
                          int popDepth,
                          int pushDepth,
                          HTML.Tag insertTag)
        Constructs an HTMLReader.
        offset - the starting offset
        popDepth - how many parents to ascend before insert new element
        pushDepth - how many parents to descend (relative to popDepth) before inserting
        insertTag - a tag to insert (may be null)
    • Method Detail

      • flush

        public void flush()
                   throws BadLocationException
        The last method called on the reader. It allows any pending changes to be flushed into the document. Since this is currently loading synchronously, the entire set of changes are pushed in at this point.
        flush in class HTMLEditorKit.ParserCallback
        BadLocationException - if the given position does not represent a valid location in the associated document.
      • handleText

        public void handleText​(char[] data,
                               int pos)
        Called by the parser to indicate a block of text was encountered.
        handleText in class HTMLEditorKit.ParserCallback
        data - a data
        pos - a position
      • handleEndTag

        public void handleEndTag​(HTML.Tag t,
                                 int pos)
        Callback from the parser. Route to the appropriate handler for the tag.
        handleEndTag in class HTMLEditorKit.ParserCallback
        t - an HTML tag
        pos - a position
      • handleEndOfLineString

        public void handleEndOfLineString​(String eol)
        This is invoked after the stream has been parsed, but before flush. eol will be one of \n, \r or \r\n, which ever is encountered the most in parsing the stream.
        handleEndOfLineString in class HTMLEditorKit.ParserCallback
        eol - value of eol
      • registerTag

        protected void registerTag​(HTML.Tag t,
                                   HTMLDocument.HTMLReader.TagAction a)
        Registers a handler for the given tag. By default all of the well-known tags will have been registered. This can be used to change the handling of a particular tag or to add support for custom tags.
        t - an HTML tag
        a - tag action handler
      • pushCharacterStyle

        protected void pushCharacterStyle()
        Pushes the current character style on a stack in preparation for forming a new nested character style.
      • popCharacterStyle

        protected void popCharacterStyle()
        Pops a previously pushed character style off the stack to return to a previous style.
      • textAreaContent

        protected void textAreaContent​(char[] data)
        Adds the given content to the textarea document. This method gets called when we are in a textarea context. Therefore all text that is seen belongs to the text area and is hence added to the TextAreaDocument associated with the text area.
        data - the given content
      • preContent

        protected void preContent​(char[] data)
        Adds the given content that was encountered in a PRE element. This synthesizes lines to hold the runs of text, and makes calls to addContent to actually add the text.
        data - the given content
      • blockOpen

        protected void blockOpen​(HTML.Tag t,
                                 MutableAttributeSet attr)
        Adds an instruction to the parse buffer to create a block element with the given attributes.
        t - an HTML tag
        attr - the attribute set
      • blockClose

        protected void blockClose​(HTML.Tag t)
        Adds an instruction to the parse buffer to close out a block element of the given type.
        t - the HTML tag
      • addContent

        protected void addContent​(char[] data,
                                  int offs,
                                  int length)
        Adds some text with the current character attributes.
        data - the content to add
        offs - the initial offset
        length - the length
      • addContent

        protected void addContent​(char[] data,
                                  int offs,
                                  int length,
                                  boolean generateImpliedPIfNecessary)
        Adds some text with the current character attributes.
        data - the content to add
        offs - the initial offset
        length - the length
        generateImpliedPIfNecessary - whether to generate implied paragraphs
      • addSpecialElement

        protected void addSpecialElement​(HTML.Tag t,
                                         MutableAttributeSet a)
        Adds content that is basically specified entirely in the attribute set.
        t - an HTML tag
        a - the attribute set