javax.swing.text.html
class HTMLDocument

java.lang.Object javax.swing.text.AbstractDocument javax.swing.text.DefaultStyledDocument javax.swing.text.html.HTMLDocument

All Implemented Interfaces:

Serializable, Document, StyledDocument

Most common way to construct:

HTMLEditorKit kit = …;

HTMLDocument doc = (HTMLDocument)kit.createDefaultDocument();

Based on 37 examples

public class HTMLDocument
extends DefaultStyledDocument

A document that models HTML. The purpose of this model is to support both browsing and editing. As a result, the structure described by an HTML document is not exactly replicated by default. The element structure that is modeled by default, is built by the class HTMLDocument.HTMLReader, which implements the HTMLEditorKit.ParserCallback protocol that the parser expects. To change the structure one can subclass HTMLReader, and reimplement the method {@link #getReader(int)} to return the new reader implementation. The documentation for HTMLReader should be consulted for the details of the default structure created. The intent is that the document be non-lossy (although reproducing the HTML format may result in a different format).

The document models only HTML, and makes no attempt to store view attributes in it. The elements are identified by the StyleContext.NameAttribute attribute, which should always have a value of type HTML.Tag that identifies the kind of element. Some of the elements (such as comments) are synthesized. The HTMLFactory uses this attribute to determine what kind of view to build.

This document supports incremental loading. The TokenThreshold property controls how much of the parse is buffered before trying to update the element structure of the document. This property is set by the EditorKit so that subclasses can disable it.

The Base property determines the URL against which relative URLs are resolved. By default, this will be the Document.StreamDescriptionProperty if the value of the property is a URL. If a <BASE> tag is encountered, the base will become the URL specified by that tag. Because the base URL is a property, it can of course be set directly.

The default content storage mechanism for this document is a gap buffer (GapContent). Alternatives can be supplied by using the constructor that takes a Content implementation.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans^TM has been added to the java.beans package. Please see {@link java.beans.XMLEncoder}.

AdditionalComments

public static final String AdditionalComments

Document property key value. The value for the key will be a Vector of Strings that are comments not found in the body.

HTMLDocument

public HTMLDocument()

Constructs an HTML document using the default buffer size and a default StyleSheet. This is a convenience method for the constructor HTMLDocument(Content, StyleSheet).

HTMLDocument

public HTMLDocument(AbstractDocument.Content c,
                    StyleSheet styles)

Constructs an HTML document with the given content storage implementation and the given style/attribute storage mechanism.

Parameters:

c - the container for the content

styles - the styles

HTMLDocument

public HTMLDocument(StyleSheet styles)

Constructs an HTML document with the default content storage implementation and the specified style/attribute storage mechanism. This is a convenience method for the constructor HTMLDocument(Content, StyleSheet).

Parameters:

styles - the styles

create

protected void create(DefaultStyledDocument.ElementSpec[] data)

Replaces the contents of the document with the given element specifications. This is called before insert if the loading is done in bursts. This is the only method called if loading the document entirely in one burst.

Overrides:

create in class DefaultStyledDocument

Parameters:

data - the new contents of the document

createBranchElement

protected Element createBranchElement(Element parent,
                                      AttributeSet a)

Creates a document branch element, that can contain other elements. This is implemented to return an element of type HTMLDocument.BlockElement.

Overrides:

createBranchElement in class AbstractDocument

Parameters:

parent - the parent element

a - the attributes

Returns:

the element

createDefaultRoot

protected AbstractDocument.AbstractElement createDefaultRoot()

Creates the root element to be used to represent the default document structure.

Overrides:

createDefaultRoot in class DefaultStyledDocument

Returns:

the element base

createLeafElement

protected Element createLeafElement(Element parent,
                                    AttributeSet a,
                                    int p0,
                                    int p1)

Creates a document leaf element that directly represents text (doesn't have any children). This is implemented to return an element of type HTMLDocument.RunElement.

Overrides:

createLeafElement in class AbstractDocument

Parameters:

parent - the parent element

a - the attributes for the element

p0 - the beginning of the range (must be at least 0)

p1 - the end of the range (must be at least p0)

Returns:

the new element

fireChangedUpdate

protected void fireChangedUpdate(DocumentEvent e)

Notifies all listeners that have registered interest for notification on this event type. The event instance is lazily created using the parameters passed into the fire method.

Overrides:

fireChangedUpdate in class AbstractDocument

Parameters:

e - the event

fireUndoableEditUpdate

protected void fireUndoableEditUpdate(UndoableEditEvent e)

Notifies all listeners that have registered interest for notification on this event type. The event instance is lazily created using the parameters passed into the fire method.

Overrides:

fireUndoableEditUpdate in class AbstractDocument

Parameters:

e - the event

getBase

public URL getBase()

Returns the location to resolve relative URLs against. By default this will be the document's URL if the document was loaded from a URL. If a base tag is found and can be parsed, it will be used as the base location.

Returns:

the base location

getElement

public Element getElement(Element e,
                          Object attribute,
                          Object value)

Returns the child element of e that contains the attribute, attribute with value value, or null if one isn't found. This is not thread-safe.

Parameters:

e - the root element where the search begins

attribute - the desired Attribute

value - the values for the specified Attribute

Returns:

the element with the specified Attribute and the specified value, or null if it can't be found

getElement

public Element getElement(String id)

Returns the element that has the given id Attribute. If the element can't be found, null is returned. Note that this method works on an Attribute, not a character tag. In the following HTML snippet: <a id="HelloThere"> the attribute is 'id' and the character tag is 'a'. This is a convenience method for getElement(RootElement, HTML.Attribute.id, id). This is not thread-safe.

Parameters:

id - the string representing the desired Attribute

Returns:

the element with the specified Attribute or null if it can't be found, or null if id is null

getIterator

public HTMLDocument.Iterator getIterator(HTML.Tag t)

Fetches an iterator for the specified HTML tag. This can be used for things like iterating over the set of anchors contained, or iterating over the input elements.

Parameters:

t - the requested HTML.Tag

Returns:

the Iterator for the given HTML tag

getParser

public HTMLEditorKit.Parser getParser()

Returns the parser that is used when inserting HTML into the existing document.

Returns:

the parser used for text insertion

getPreservesUnknownTags

public boolean getPreservesUnknownTags()

Returns the behavior the parser observes when encountering unknown tags.

Returns:

true if unknown tags are to be preserved when parsing

getReader

public HTMLEditorKit.ParserCallback getReader(int pos)

Fetches the reader for the parser to use when loading the document with HTML. This is implemented to return an instance of HTMLDocument.HTMLReader. Subclasses can reimplement this method to change how the document gets structured if desired. (For example, to handle custom tags, or structurally represent character style elements.)

Parameters:

pos - the starting position

Returns:

the reader used by the parser to load the document

getReader

public HTMLEditorKit.ParserCallback getReader(int pos,
                                              int popDepth,
                                              int pushDepth,
                                              HTML.Tag insertTag)

Returns the reader for the parser to use to load the document with HTML. This is implemented to return an instance of HTMLDocument.HTMLReader. Subclasses can reimplement this method to change how the document gets structured if desired. (For example, to handle custom tags, or structurally represent character style elements.)

This is a convenience method for getReader(int, int, int, HTML.Tag, TRUE).

Parameters:

pos

popDepth - the number of ElementSpec.EndTagTypes to generate before inserting

pushDepth - the number of ElementSpec.StartTagTypes with a direction of ElementSpec.JoinNextDirection that should be generated before inserting, but after the end tags have been generated

insertTag - the first tag to start inserting into document

Returns:

the reader used by the parser to load the document

getStyleSheet

public StyleSheet getStyleSheet()

Fetches the StyleSheet with the document-specific display rules (CSS) that were specified in the HTML document itself.

Returns:

the StyleSheet

getTokenThreshold

public int getTokenThreshold()

Gets the number of tokens to buffer before trying to update the documents element structure. The default value is Integer.MAX_VALUE.

Returns:

the number of tokens to buffer

insert

protected void insert(int offset,
                      DefaultStyledDocument.ElementSpec[] data)
               throws BadLocationException

Inserts new elements in bulk. This is how elements get created in the document. The parsing determines what structure is needed and creates the specification as a set of tokens that describe the edit while leaving the document free of a write-lock. This method can then be called in bursts by the reader to acquire a write-lock for a shorter duration (i.e. while the document is actually being altered).

Overrides:

insert in class DefaultStyledDocument

Parameters:

offset - the starting offset

data - the element data

Throws:

BadLocationException - if the given position does not represent a valid location in the associated document.

insertAfterEnd

public void insertAfterEnd(Element elem,
                           String htmlText)
                    throws BadLocationException,
                           IOException

Inserts the HTML specified as a string after the the end of the given element.

For this to work correcty, the document must have an HTMLEditorKit.Parser set. This will be the case if the document was created from an HTMLEditorKit via the createDefaultDocument method.

Parameters:

elem - the element to be the root for the new text

htmlText - the string to be parsed and assigned to elem

Throws:

BadLocationException

IOException

insertAfterStart

public void insertAfterStart(Element elem,
                             String htmlText)
                      throws BadLocationException,
                             IOException

Inserts the HTML specified as a string at the start of the element.

For this to work correcty, the document must have an HTMLEditorKit.Parser set. This will be the case if the document was created from an HTMLEditorKit via the createDefaultDocument method.

Parameters:

elem - the branch element to be the root for the new text

htmlText - the string to be parsed and assigned to elem

Throws:

BadLocationException

IOException

insertBeforeEnd

public void insertBeforeEnd(Element elem,
                            String htmlText)
                     throws BadLocationException,
                            IOException

Inserts the HTML specified as a string at the end of the element.

If elem's children are leaves, and the character at a elem.getEndOffset() - 1 is a newline, this will insert before the newline so that there isn't text after the newline.

For this to work correcty, the document must have an HTMLEditorKit.Parser set. This will be the case if the document was created from an HTMLEditorKit via the createDefaultDocument method.

Parameters:

elem - the element to be the root for the new text

htmlText - the string to be parsed and assigned to elem

Throws:

BadLocationException

IOException

insertBeforeStart

public void insertBeforeStart(Element elem,
                              String htmlText)
                       throws BadLocationException,
                              IOException

Inserts the HTML specified as a string before the start of the given element.

For this to work correcty, the document must have an HTMLEditorKit.Parser set. This will be the case if the document was created from an HTMLEditorKit via the createDefaultDocument method.

Parameters:

elem - the element to be the root for the new text

htmlText - the string to be parsed and assigned to elem

Throws:

BadLocationException

IOException

insertUpdate

protected void insertUpdate(AbstractDocument.DefaultDocumentEvent chng,
                            AttributeSet attr)

Updates document structure as a result of text insertion. This will happen within a write lock. This implementation simply parses the inserted content for line breaks and builds up a set of instructions for the element buffer.

Overrides:

insertUpdate in class DefaultStyledDocument

Parameters:

chng - a description of the document change

attr - the attributes

processHTMLFrameHyperlinkEvent

public void processHTMLFrameHyperlinkEvent(HTMLFrameHyperlinkEvent e)

Processes HyperlinkEvents that are generated by documents in an HTML frame. The HyperlinkEvent type, as the parameter suggests, is HTMLFrameHyperlinkEvent. In addition to the typical information contained in a HyperlinkEvent, this event contains the element that corresponds to the frame in which the click happened (the source element) and the target name. The target name has 4 possible values:

• _self
• _parent
• _top
• a named frame

If target is _self, the action is to change the value of the HTML.Attribute.SRC attribute and fires a ChangedUpdate event.

If the target is _parent, then it deletes the parent element, which is a <FRAMESET> element, and inserts a new <FRAME> element, and sets its HTML.Attribute.SRC attribute to have a value equal to the destination URL and fire a RemovedUpdate and InsertUpdate.

If the target is _top, this method does nothing. In the implementation of the view for a frame, namely the FrameView, the processing of _top is handled. Given that _top implies replacing the entire document, it made sense to handle this outside of the document that it will replace.

If the target is a named frame, then the element hierarchy is searched for an element with a name equal to the target, its HTML.Attribute.SRC attribute is updated and a ChangedUpdate event is fired.

Parameters:

e - the event

setBase

public void setBase(URL u)

Sets the location to resolve relative URLs against. By default this will be the document's URL if the document was loaded from a URL. If a base tag is found and can be parsed, it will be used as the base location.

This also sets the base of the StyleSheet to be u as well as the base of the document.

Parameters:

u - the desired base URL

setInnerHTML

public void setInnerHTML(Element elem,
                         String htmlText)
                  throws BadLocationException,
                         IOException

Replaces the children of the given element with the contents specified as an HTML string.

This will be seen as at least two events, n inserts followed by a remove.

For this to work correcty, the document must have an HTMLEditorKit.Parser set. This will be the case if the document was created from an HTMLEditorKit via the createDefaultDocument method.

Parameters:

elem - the branch element whose children will be replaced

htmlText - the string to be parsed and assigned to elem

Throws:

BadLocationException

IOException

setOuterHTML

public void setOuterHTML(Element elem,
                         String htmlText)
                  throws BadLocationException,
                         IOException

Replaces the given element in the parent with the contents specified as an HTML string.

This will be seen as at least two events, n inserts followed by a remove.

When replacing a leaf this will attempt to make sure there is a newline present if one is needed. This may result in an additional element being inserted. Consider, if you were to replace a character element that contained a newline with <img> this would create two elements, one for the image, ane one for the newline.

If you try to replace the element at length you will most likely end up with two elements, eg setOuterHTML(getCharacterElement (getLength()), "blah") will result in two leaf elements at the end, one representing 'blah', and the other representing the end element.

For this to work correcty, the document must have an HTMLEditorKit.Parser set. This will be the case if the document was created from an HTMLEditorKit via the createDefaultDocument method.

Parameters:

elem - the branch element whose children will be replaced

htmlText - the string to be parsed and assigned to elem

Throws:

BadLocationException

IOException

setParagraphAttributes

public void setParagraphAttributes(int offset,
                                   int length,
                                   AttributeSet s,
                                   boolean replace)

Sets attributes for a paragraph.

This method is thread safe, although most Swing methods are not. Please see How to Use Threads for more information.

Overrides:

setParagraphAttributes in class DefaultStyledDocument

Parameters:

offset - the offset into the paragraph (must be at least 0)

length - the number of characters affected (must be at least 0)

s - the attributes

replace - whether to replace existing attributes, or merge them

setParser

public void setParser(HTMLEditorKit.Parser parser)

Sets the parser that is used by the methods that insert html into the existing document, such as setInnerHTML, and setOuterHTML.

HTMLEditorKit.createDefaultDocument will set the parser for you. If you create an HTMLDocument by hand, be sure and set the parser accordingly.

Parameters:

parser - the parser to be used for text insertion

setPreservesUnknownTags

public void setPreservesUnknownTags(boolean preservesTags)

Determines how unknown tags are handled by the parser. If set to true, unknown tags are put in the model, otherwise they are dropped.

Parameters:

preservesTags - true if unknown tags should be saved in the model, otherwise tags are dropped

setTokenThreshold

public void setTokenThreshold(int n)

Sets the number of tokens to buffer before trying to update the documents element structure.

Parameters:

n - the number of tokens to buffer