projectviewer.persist

Class NodeHandler

java.lang.Object

projectviewer.persist.NodeHandler

Direct Known Subclasses:

DirectoryNodeHandler, FileNodeHandler, FilterNodeHandler, OpenFileNodeHandler, ProjectNodeHandler, PropertyNodeHandler

public abstract class NodeHandler
extends java.lang.Object

A node handler is a class that takes care of loading an saving nodes to/from the configuration file.

Loading

When the parser finds a node that macthes the node name published by the handler, it calls the callback method with the attributes read from the file. The handler then should instantiate a node, fill any data and return the object.

Saving

The handler also publishes the class of the node (a java.lang.Class object) to register itself as the handler to save nodes of that type to the config file. When traversing the node tree, each time a node of that class is found, the appropriate handler callback method will be called.

Author:

Marcelo Vanzin

Field Summary

Fields

Modifier and Type	Field and Description
protected static java.lang.String	VCSTATE_ATTR

Constructor Summary

Constructors

Constructor and Description
NodeHandler()

Method Summary

Methods

Modifier and Type	Method and Description
abstract VPTNode	createNode(org.xml.sax.Attributes attrs, VPTProject project) Instantiates a VPTNode based on the information given in the attribute list.
protected java.lang.String	fixPath(java.lang.String src) Translates the directory separators read from the XML according the file system.
abstract java.lang.Class	getNodeClass() Returns the class of the nodes that should be delegated to this handler when saving node data to the config file.
abstract java.lang.String	getNodeName() Returns the name of the tag representing nodes handled by this handler when loading the project's XML file.
abstract boolean	hasChildren() Returns whether the node(s) handled by this handler are expected to have children or not.
abstract boolean	isChild() Returns whether the node is a child of some other node or not.
abstract void	saveNode(VPTNode node, java.io.Writer out) Saves a node to the given Writer.
protected void	startElement(java.lang.String name, java.io.Writer out) Writes the start of an element to the given writer, using the given string as the node name.
protected void	startElement(java.io.Writer out) Writes the start of an element to the given writer.
protected void	writeAttr(java.lang.String name, java.lang.String value, java.io.Writer out) Writes an attribute to the writer.

Methods inherited from class java.lang.Object

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

Field Detail

VCSTATE_ATTR

protected static final java.lang.String VCSTATE_ATTR

See Also:

Constant Field Values

Constructor Detail

NodeHandler

public NodeHandler()

Method Detail

getNodeName

public abstract java.lang.String getNodeName()

Returns the name of the tag representing nodes handled by this handler when loading the project's XML file.

getNodeClass

public abstract java.lang.Class getNodeClass()

Returns the class of the nodes that should be delegated to this handler when saving node data to the config file.

isChild

public abstract boolean isChild()

Returns whether the node is a child of some other node or not. For example, property nodes are not children of any other nodes, they simply add a property to a project.

This controls whether the node will be added to the parent node read from the XML file after instantiation.

hasChildren

public abstract boolean hasChildren()

Returns whether the node(s) handled by this handler are expected to have children or not.

createNode

public abstract VPTNode createNode(org.xml.sax.Attributes attrs,
                 VPTProject project)

Instantiates a VPTNode based on the information given in the attribute list.

Parameters:

attrs - The attributes read from the config file.

project - The project that holds this node.

Since:

PV 2.1.3.4 (older version have a different method signature)

saveNode

public abstract void saveNode(VPTNode node,
            java.io.Writer out)
                       throws java.io.IOException

Saves a node to the given Writer. The node is guaranteed to be an instance of the class returned by the getNodeClass() method.

This method should create the tag, but it shouldn't close it, even if it's an empty tag. Closing tags is done by the PersistenceManager based on the value returned by hasChildren(). The config file format does not support text elements inside other elements, so don't use them when saving nodes or you won't be able to read them later.

Throws:

java.io.IOException

startElement

protected void startElement(java.io.Writer out)
                     throws java.io.IOException

Writes the start of an element to the given writer.

Throws:

java.io.IOException

startElement

protected void startElement(java.lang.String name,
                java.io.Writer out)
                     throws java.io.IOException

Writes the start of an element to the given writer, using the given string as the node name. This writer the opening < symbol and the node name, but does not writed the closing >, since attributed may still need to be written.

Throws:

java.io.IOException

writeAttr

protected void writeAttr(java.lang.String name,
             java.lang.String value,
             java.io.Writer out)
                  throws java.io.IOException

Writes an attribute to the writer.

Throws:

java.io.IOException

fixPath

protected final java.lang.String fixPath(java.lang.String src)

Translates the directory separators read from the XML according the file system.