diva.graph.schematic

Class GraphDocument

java.lang.Object

diva.gui.AbstractDocument

diva.graph.schematic.GraphDocument

All Implemented Interfaces:

Document

public class GraphDocument
extends AbstractDocument

A class representing graph-structured documents. This class can read files to construct an instance of GraphModel, and write a GraphModel out to a file.

This is one of two classes that must be provided to produce a complete application using the diva.gui framework. (The other is diva.gui.Application -- see the CanvasDemo class.) Generally, the easiest way to implement diva.gui.Document is to extend diva.gui.AbstractDocument.

This class implements those methods that are left abstract in diva.gui.AbstractDocument. This is a set of methods that deal with loading the document from a file or URL and vice versa, such as close(), open(), save(), and saveAs(). These methods simply implement the "raw" functionality implied by the method names; they do not perform functions such as querying the user for whether to save a file before closing. (That function is performed by an instance of diva.gui.StoragePolicy.)

To read and write canvas data, it uses the diva.util.xml utility package. In general, there is no need for applications to use the XML utilities; however, it does make it very simple and fast to construct a working application with complete file I/O. See the various method comments for further imformation.

Version:

$Revision: 1.5 $

Author:

John Reekie (johnr@eecs.berkeley.edu)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	GraphDocument.Factory GraphDocument.Factory is a factory for graph documents.

Constructor Summary

Constructors

Constructor and Description
GraphDocument(Application a) Construct a graph document that is owned by the given application.

Method Summary

Modifier and Type	Method and Description
void	close() Close the document.
BasicGraphModel	getGraphModel() Get the graph data model.
XmlDocument	getXmlDocument() Get the XML document that contains the raw XML data.
void	open() Open the document from its current file.
void	save() Save the document to the current file.
void	saveAs(File file) Save the document to the given file.
void	saveAs(URL url) Save the document to the given file.
void	setGraphModel(BasicGraphModel m) Set the graph data model.
String	toString() Print information about the graph document

Methods inherited from class diva.gui.AbstractDocument

addPropertyChangeListener, getApplication, getEditSupport, getFile, getShortTitle, getTitle, getUndoManager, getURL, isDirty, isEditable, isWritable, removePropertyChangeListener, setDirty, setEditable, setFile, setURL, setWritable

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

GraphDocument

public GraphDocument(Application a)

Construct a graph document that is owned by the given application. It contains an empty BasicGraph as its data.

Method Detail

close

public void close()
           throws Exception

Close the document. This method doesn't do anything, as graph data doesn't change.

Specified by:

close in interface Document

Overrides:

close in class AbstractDocument

Throws:

Exception - If the close operation fails.

getGraphModel

public BasicGraphModel getGraphModel()

Get the graph data model.

getXmlDocument

public XmlDocument getXmlDocument()

Get the XML document that contains the raw XML data.

open

public void open()
          throws Exception

Open the document from its current file. If successful, create and remember a Graph model.

The implementation of this method uses the diva.xml package:

• Create an instance of the XmlDocument class
• Create an instance of the XmlReader class and pass the document to it to parse the XML file
• Traverse the XmlDocument to construct an instance of Graph

Specified by:

open in interface Document

Specified by:

open in class AbstractDocument

Throws:

Exception - If there is no file, or if the I/O operation failed.

save

public void save()
          throws Exception

Save the document to the current file. See the saveAs() method for more information.

Specified by:

save in interface Document

Specified by:

save in class AbstractDocument

Throws:

Exception - If there is no file, or if the I/O operation failed.

saveAs

public void saveAs(File file)
            throws Exception

Save the document to the given file. Note that this method does not change the file attribute to the new File object.

The implementation of this class uses the diva.util.xml package:

• If there is not already an instance of XmlDocument (eg created when parsing), create one now.
• Clear the contents of the XML document.
• Use an instance of XMLBuilder to construct an XML tree.
• Use an instance of XmlWriter to write the document to disk.

Specified by:

saveAs in interface Document

Specified by:

saveAs in class AbstractDocument

Throws:

Exception - If the I/O operation failed.

See Also:

AbstractDocument.save()

saveAs

public void saveAs(URL url)
            throws Exception

Save the document to the given file. This method uses diva.util.xml to do the work -- see the saveAs(File) method for more description. It will probably fail if the URL is not a file-based url.

Specified by:

saveAs in interface Document

Specified by:

saveAs in class AbstractDocument

Throws:

Exception - Always

See Also:

AbstractDocument.save()

setGraphModel

public void setGraphModel(BasicGraphModel m)

Set the graph data model.

toString

public String toString()

Print information about the graph document

Overrides:

toString in class Object