/*
* @(#)Document.java 1.43 03/12/19
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package javax.swing.text;
import javax.swing.event.*;
/**
* <p>
* The <code>Document</code> is a container for text that serves
* as the model for swing text components. The goal for this
* interface is to scale from very simple needs (a plain text textfield)
* to complex needs (an HTML or XML document, for example).
*
* <p><b><font size=+1>Content</font></b>
* <p>
* At the simplest level, text can be
* modeled as a linear sequence of characters. To support
* internationalization, the Swing text model uses
* <a href="http://www.unicode.org/">unicode</a> characters.
* The sequence of characters displayed in a text component is
* generally referred to as the component's <em>content</em>.
* <p>
* To refer to locations within the sequence, the coordinates
* used are the location between two characters. As the diagram
* below shows, a location in a text document can be referred to
* as a position, or an offset. This position is zero-based.
* <p align=center><img src="doc-files/Document-coord.gif"
* alt="The following text describes this graphic.">
* <p>
* In the example, if the content of a document is the
* sequence "The quick brown fox," as shown in the preceding diagram,
* the location just before the word "The" is 0, and the location after
* the word "The" and before the whitespace that follows it is 3.
* The entire sequence of characters in the sequence "The" is called a
* <em>range</em>.
* <p>The following methods give access to the character data
* that makes up the content.
* <ul>
* <li><a href="#getLength()">getLength()</a>
* <li><a href="#getText(int, int)">getText(int, int)</a>
* <li><a href="#getText(int, int, javax.swing.text.Segment)">getText(int, int, Segment)</a>
* </ul>
* <p><b><font size=+1>Structure</font></b>
* <p>
* Text is rarely represented simply as featureless content. Rather,
* text typically has some sort of structure associated with it.
* Exactly what structure is modeled is up to a particular Document
* implementation. It might be as simple as no structure (i.e. a
* simple text field), or it might be something like diagram below.
* <p align=center><img src="doc-files/Document-structure.gif"
* alt="Diagram shows Book->Chapter->Paragraph">
* <p>
* The unit of structure (i.e. a node of the tree) is referred to
* by the <a href="Element.html">Element</a> interface. Each Element
* can be tagged with a set of attributes. These attributes
* (name/value pairs) are defined by the
* <a href="AttributeSet.html">AttributeSet</a> interface.
* <p>The following methods give access to the document structure.
* <ul>
* <li><a href="#getDefaultRootElement()">getDefaultRootElement</a>
* <li><a href="#getRootElements()">getRootElements</a>
* </ul>
*
* <p><b><font size=+1>Mutations</font></b>
* <p>
* All documents need to be able to add and remove simple text.
* Typically, text is inserted and removed via gestures from
* a keyboard or a mouse. What effect the insertion or removal
* has upon the document structure is entirely up to the
* implementation of the document.
* <p>The following methods are related to mutation of the
* document content:
* <ul>
* <li><a href="#insertString(int, java.lang.String, javax.swing.text.AttributeSet)">insertString(int, String, AttributeSet)</a>
* <li><a href="#remove(int, int)">remove(int, int)</a>
* <li><a href="#createPosition(int)">createPosition(int)</a>
* </ul>
*
* <p><b><font size=+1>Notification</font></b>
* <p>
* Mutations to the <code>Document</code> must be communicated to
* interested observers. The notification of change follows the event model
* guidelines that are specified for JavaBeans. In the JavaBeans
* event model, once an event notification is dispatched, all listeners
* must be notified before any further mutations occur to the source
* of the event. Further, order of delivery is not guaranteed.
* <p>
* Notification is provided as two separate events,
* <a href="../event/DocumentEvent.html">DocumentEvent</a>, and
* <a href="../event/UndoableEditEvent.html">UndoableEditEvent</a>.
* If a mutation is made to a <code>Document</code> through its api,
* a <code>DocumentEvent</code> will be sent to all of the registered
* <code>DocumentListeners</code>. If the <code>Document</code>
* implementation supports undo/redo capabilities, an
* <code>UndoableEditEvent</code> will be sent
* to all of the registered <code>UndoableEditListener</code>s.
* If an undoable edit is undone, a <code>DocumentEvent</code> should be
* fired from the Document to indicate it has changed again.
* In this case however, there should be no <code>UndoableEditEvent</code>
* generated since that edit is actually the source of the change
* rather than a mutation to the <code>Document</code> made through its
* api.
* <p align=center><img src="doc-files/Document-notification.gif"
* alt="The preceeding text describes this graphic.">
* <p>
* Referring to the above diagram, suppose that the component shown
* on the left mutates the document object represented by the blue
* rectangle. The document responds by dispatching a DocumentEvent to
* both component views and sends an UndoableEditEvent to the listening
* logic, which maintains a history buffer.
* <p>
* Now suppose that the component shown on the right mutates the same
* document. Again, the document dispatches a DocumentEvent to both
* component views and sends an UndoableEditEvent to the listening logic
* that is maintaining the history buffer.
* <p>
* If the history buffer is then rolled back (i.e. the last UndoableEdit
* undone), a DocumentEvent is sent to both views, causing both of them to
* reflect the undone mutation to the document (that is, the
* removal of the right component's mutation). If the history buffer again
* rolls back another change, another DocumentEvent is sent to both views,
* causing them to reflect the undone mutation to the document -- that is,
* the removal of the left component's mutation.
* <p>
* The methods related to observing mutations to the document are:
* <ul>
* <li><a href="#addDocumentListener(javax.swing.event.DocumentListener)">addDocumentListener(DocumentListener)</a>
* <li><a href="#removeDocumentListener(javax.swing.event.DocumentListener)">removeDocumentListener(DocumentListener)</a>
* <li><a href="#addUndoableEditListener(javax.swing.event.UndoableEditListener)">addUndoableEditListener(UndoableEditListener)</a>
* <li><a href="#removeUndoableEditListener(javax.swing.event.UndoableEditListener)">removeUndoableEditListener(UndoableEditListener)</a>
* </ul>
*
* <p><b><font size=+1>Properties</font></b>
* <p>
* Document implementations will generally have some set of properties
* associated with them at runtime. Two well known properties are the
* <a href="#StreamDescriptionProperty">StreamDescriptionProperty</a>,
* which can be used to describe where the <code>Document</code> came from,
* and the <a href="#TitleProperty">TitleProperty</a>, which can be used to
* name the <code>Document</code>. The methods related to the properties are:
* <ul>
* <li><a href="#getProperty(java.lang.Object)">getProperty(Object)</a>
* <li><a href="#putProperty(java.lang.Object, java.lang.Object)">putProperty(Object, Object)</a>
* </ul>
*
* <p>For more information on the <code>Document</code> class, see
* <a href="http://java.sun.com/products/jfc/tsc">The Swing Connection</a>
* and most particularly the article,
* <a href="http://java.sun.com/products/jfc/tsc/articles/text/element_interface">
* The Element Interface</a>.
*
* @author Timothy Prinzing
* @version 1.43 12/19/03
*
* @see javax.swing.event.DocumentEvent
* @see javax.swing.event.DocumentListener
* @see javax.swing.event.UndoableEditEvent
* @see javax.swing.event.UndoableEditListener
* @see Element
* @see Position
* @see AttributeSet
*/
public interface Document {
/**
* Returns number of characters of content currently
* in the document.
*
* @return number of characters >= 0
*/
public int getLength();
/**
* Registers the given observer to begin receiving notifications
* when changes are made to the document.
*
* @param listener the observer to register
* @see Document#removeDocumentListener
*/
public void addDocumentListener(DocumentListener listener);
/**
* Unregisters the given observer from the notification list
* so it will no longer receive change updates.
*
* @param listener the observer to register
* @see Document#addDocumentListener
*/
public void removeDocumentListener(DocumentListener listener);
/**
* Registers the given observer to begin receiving notifications
* when undoable edits are made to the document.
*
* @param listener the observer to register
* @see javax.swing.event.UndoableEditEvent
*/
public void addUndoableEditListener(UndoableEditListener listener);
/**
* Unregisters the given observer from the notification list
* so it will no longer receive updates.
*
* @param listener the observer to register
* @see javax.swing.event.UndoableEditEvent
*/
public void removeUndoableEditListener(UndoableEditListener listener);
/**
* Gets the properties associated with the document.
*
* @param key a non-<code>null</code> property key
* @return the properties
* @see #putProperty(Object, Object)
*/
public Object getProperty(Object key);
/**
* Associates a property with the document. Two standard
* property keys provided are: <a href="#StreamDescriptionProperty">
* <code>StreamDescriptionProperty</code></a> and
* <a href="#TitleProperty"><code>TitleProperty</code></a>.
* Other properties, such as author, may also be defined.
*
* @param key the non-<code>null</code> property key
* @param value the property value
* @see #getProperty(Object)
*/
public void putProperty(Object key, Object value);
/**
* Removes a portion of the content of the document.
* This will cause a DocumentEvent of type
* DocumentEvent.EventType.REMOVE to be sent to the
* registered DocumentListeners, unless an exception
* is thrown. The notification will be sent to the
* listeners by calling the removeUpdate method on the
* DocumentListeners.
* <p>
* To ensure reasonable behavior in the face
* of concurrency, the event is dispatched after the
* mutation has occurred. This means that by the time a
* notification of removal is dispatched, the document
* has already been updated and any marks created by
* <code>createPosition</code> have already changed.
* For a removal, the end of the removal range is collapsed
* down to the start of the range, and any marks in the removal
* range are collapsed down to the start of the range.
* <p align=center><img src="doc-files/Document-remove.gif"
* alt="Diagram shows removal of 'quick' from 'The quick brown fox.'">
* <p>
* If the Document structure changed as result of the removal,
* the details of what Elements were inserted and removed in
* response to the change will also be contained in the generated
* DocumentEvent. It is up to the implementation of a Document
* to decide how the structure should change in response to a
* remove.
* <p>
* If the Document supports undo/redo, an UndoableEditEvent will
* also be generated.
*
* @param offs the offset from the beginning >= 0
* @param len the number of characters to remove >= 0
* @exception BadLocationException some portion of the removal range
* was not a valid part of the document. The location in the exception
* is the first bad position encountered.
* @see javax.swing.event.DocumentEvent
* @see javax.swing.event.DocumentListener
* @see javax.swing.event.UndoableEditEvent
* @see javax.swing.event.UndoableEditListener
*/
public void remove(int offs, int len) throws BadLocationException;
/**
* Inserts a string of content. This will cause a DocumentEvent
* of type DocumentEvent.EventType.INSERT to be sent to the
* registered DocumentListers, unless an exception is thrown.
* The DocumentEvent will be delivered by calling the
* insertUpdate method on the DocumentListener.
* The offset and length of the generated DocumentEvent
* will indicate what change was actually made to the Document.
* <p align=center><img src="doc-files/Document-insert.gif"
* alt="Diagram shows insertion of 'quick' in 'The quick brown fox'">
* <p>
* If the Document structure changed as result of the insertion,
* the details of what Elements were inserted and removed in
* response to the change will also be contained in the generated
* DocumentEvent. It is up to the implementation of a Document
* to decide how the structure should change in response to an
* insertion.
* <p>
* If the Document supports undo/redo, an UndoableEditEvent will
* also be generated.
*
* @param offset the offset into the document to insert the content >= 0.
* All positions that track change at or after the given location
* will move.
* @param str the string to insert
* @param a the attributes to associate with the inserted
* content. This may be null if there are no attributes.
* @exception BadLocationException the given insert position is not a valid
* position within the document
* @see javax.swing.event.DocumentEvent
* @see javax.swing.event.DocumentListener
* @see javax.swing.event.UndoableEditEvent
* @see javax.swing.event.UndoableEditListener
*/
public void insertString(int offset, String str, AttributeSet a) throws BadLocationException;
/**
* Fetches the text contained within the given portion
* of the document.
*
* @param offset the offset into the document representing the desired
* start of the text >= 0
* @param length the length of the desired string >= 0
* @return the text, in a String of length >= 0
* @exception BadLocationException some portion of the given range
* was not a valid part of the document. The location in the exception
* is the first bad position encountered.
*/
public String getText(int offset, int length) throws BadLocationException;
/**
* Fetches the text contained within the given portion
* of the document.
* <p>
* If the partialReturn property on the txt parameter is false, the
* data returned in the Segment will be the entire length requested and
* may or may not be a copy depending upon how the data was stored.
* If the partialReturn property is true, only the amount of text that
* can be returned without creating a copy is returned. Using partial
* returns will give better performance for situations where large
* parts of the document are being scanned. The following is an example
* of using the partial return to access the entire document:
* <p>
* <pre><code>
*
* int nleft = doc.getDocumentLength();
* Segment text = new Segment();
* int offs = 0;
* text.setPartialReturn(true);
* while (nleft > 0) {
* doc.getText(offs, nleft, text);
* // do someting with text
* nleft -= text.count;
* offs += text.count;
* }
*
* </code></pre>
*
* @param offset the offset into the document representing the desired
* start of the text >= 0
* @param length the length of the desired string >= 0
* @param txt the Segment object to return the text in
*
* @exception BadLocationException Some portion of the given range
* was not a valid part of the document. The location in the exception
* is the first bad position encountered.
*/
public void getText(int offset, int length, Segment txt) throws BadLocationException;
/**
* Returns a position that represents the start of the document. The
* position returned can be counted on to track change and stay
* located at the beginning of the document.
*
* @return the position
*/
public Position getStartPosition();
/**
* Returns a position that represents the end of the document. The
* position returned can be counted on to track change and stay
* located at the end of the document.
*
* @return the position
*/
public Position getEndPosition();
/**
* This method allows an application to mark a place in
* a sequence of character content. This mark can then be
* used to tracks change as insertions and removals are made
* in the content. The policy is that insertions always
* occur prior to the current position (the most common case)
* unless the insertion location is zero, in which case the
* insertion is forced to a position that follows the
* original position.
*
* @param offs the offset from the start of the document >= 0
* @return the position
* @exception BadLocationException if the given position does not
* represent a valid location in the associated document
*/
public Position createPosition(int offs) throws BadLocationException;
/**
* Returns all of the root elements that are defined.
* <p>
* Typically there will be only one document structure, but the interface
* supports building an arbitrary number of structural projections over the
* text data. The document can have multiple root elements to support
* multiple document structures. Some examples might be:
* </p>
* <ul>
* <li>Text direction.
* <li>Lexical token streams.
* <li>Parse trees.
* <li>Conversions to formats other than the native format.
* <li>Modification specifications.
* <li>Annotations.
* </ul>
*
* @return the root element
*/
public Element[] getRootElements();
/**
* Returns the root element that views should be based upon,
* unless some other mechanism for assigning views to element
* structures is provided.
*
* @return the root element
*/
public Element getDefaultRootElement();
/**
* Allows the model to be safely rendered in the presence
* of concurrency, if the model supports being updated asynchronously.
* The given runnable will be executed in a way that allows it
* to safely read the model with no changes while the runnable
* is being executed. The runnable itself may <em>not</em>
* make any mutations.
*
* @param r a <code>Runnable</code> used to render the model
*/
public void render(Runnable r);
/**
* The property name for the description of the stream
* used to initialize the document. This should be used
* if the document was initialized from a stream and
* anything is known about the stream.
*/
public static final String StreamDescriptionProperty = "stream";
/**
* The property name for the title of the document, if
* there is one.
*/
public static final String TitleProperty = "title";
}
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