org.modeshape.graph.connector.base
Class PathWorkspace<NodeType extends PathNode>

java.lang.Object
  org.modeshape.graph.connector.base.PathWorkspace<NodeType>

Type Parameters:

NodeType - the type of node

All Implemented Interfaces:

Workspace

Direct Known Subclasses:

SvnWorkspace

@NotThreadSafe
public abstract class PathWorkspace<NodeType extends PathNode>
extends Object
implements Workspace

The Workspace implementation that represents all nodes as PathNode objects and stores them in an internal data structure that allows for nodes to be accessed via a Path.

Subclasses are required to provide thread-safe access and modification of the state within the encapsulated data structure, since multiple Transaction implementations may be committing changes to the data structure at the same time. However, this class does not provide any thread-safety, since the nature of the thread-safety will almost certainly depend on the actual implementation. For example, a subclass may use a lock, or it may use a map implementation that provides the thread-safety.

Nested Class Summary

static interface

PathWorkspace.ChangeCommand<NodeType extends PathNode> A specific operation that mutates the underlying persistent repository.

Field Summary

protected PathFactory

pathFactory

Constructor Summary

PathWorkspace(ExecutionContext context, String name, UUID rootNodeUuid)
Create a new instance of the workspace.

PathWorkspace(String name, PathWorkspace<NodeType> originalToClone)
Create a new instance of the workspace.

Method Summary

void	commit(List<PathWorkspace.ChangeCommand<NodeType>> commands) Successively (and in order) apply the changes from the list of pending commands All validation for each of the objects (including validation of resource availability in the underlying persistent store) should be performed prior to invoking this method.
PathWorkspace.ChangeCommand<NodeType>	createMoveCommand(NodeType source, NodeType target) Create a change command that represents the movement of a node.
PathWorkspace.ChangeCommand<NodeType>	createPutCommand(NodeType oldNode, NodeType node) Create a change command for the required update to the given node
PathWorkspace.ChangeCommand<NodeType>	createRemoveCommand(Path path) Create a change command for the removal of the given node and its descendants
String	getName() Returns the name of the workspace.
abstract NodeType	getNode(Path path) Get the node with the supplied path.
abstract NodeType	getRootNode() Get the root node in this workspace.
protected UUID	getRootNodeUuid()
boolean	hasNodeCache() Indicates whether this workspace has a node cache.
NodeType	moveNode(NodeType source, NodeType target) Move the node from it's previous location to the new location, overwriting any previous node at that location.
NodeType	putNode(NodeType node) Save this node into the workspace, overwriting any previous record of the node.
void	removeAll() Remove all of the nodes in this workspace, and make sure there is a single root node with no properties and no children.
NodeType	removeNode(Path path) Remove this node and its descendants from the workspace.
String	toString()
Location	verifyNodeExists(Path path) Verify that the supplied node exists.

Methods inherited from class java.lang.Object

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

Field Detail

pathFactory

protected final PathFactory pathFactory

Constructor Detail

PathWorkspace

public PathWorkspace(ExecutionContext context,
                     String name,
                     UUID rootNodeUuid)

Create a new instance of the workspace.

Parameters:

context - the execution context for this workspace; may not be null

name - the workspace name; may not be null

rootNodeUuid - the root node that is expected to already exist in the map

PathWorkspace

public PathWorkspace(String name,
                     PathWorkspace<NodeType> originalToClone)

Create a new instance of the workspace.

Parameters:

name - the workspace name; may not be null

originalToClone - the workspace that is to be cloned; may not be null

Method Detail

getName

public String getName()

Returns the name of the workspace. There can only be one workspace with a given name per repository.

Specified by:

getName in interface Workspace

Returns:

the name of the workspace

See Also:

Workspace.getName()

getRootNodeUuid

protected UUID getRootNodeUuid()

getRootNode

public abstract NodeType getRootNode()

Get the root node in this workspace.

Returns:

the root node; never null

getNode

public abstract NodeType getNode(Path path)

Get the node with the supplied path.

Parameters:

path - the path to the node

Returns:

the node state as known by this workspace, or null if no such node exists in this workspace

verifyNodeExists

public Location verifyNodeExists(Path path)

Verify that the supplied node exists.

Parameters:

path - the path of the node; may not be null

Returns:

the location of the node if it exists, or null if it does not

putNode

public NodeType putNode(NodeType node)

Save this node into the workspace, overwriting any previous record of the node. This method should be overridden by writable path workspace implementations that use the default PathWorkspace.ChangeCommand implementations.

Parameters:

node - the new node; may not be null

Returns:

the previous node state, or null if the node is new to this workspace

Throws:

UnsupportedOperationException - by default, subclasses should override this method so that this exception is not thrown

See Also:

createMoveCommand(PathNode, PathNode), createPutCommand(PathNode, PathNode), createRemoveCommand(Path)

moveNode

public NodeType moveNode(NodeType source,
                         NodeType target)

Move the node from it's previous location to the new location, overwriting any previous node at that location. This method should be overridden by writable path workspace implementations that use the default PathWorkspace.ChangeCommand implementations.

The move operation is intended to reflect changes to the node's name or parent only. Changes to the children or properties of the node should be reflected separately in a put command of some sort. The details of the put command are implementation-specific.

Parameters:

source - the original version of the node to be moved; may not be null

target - the new version (implying a change to the name or parent) of the node to be moved; may not be null

Returns:

the new node state;may not be null

Throws:

UnsupportedOperationException - by default, subclasses should override this method so that this exception is not thrown

See Also:

createMoveCommand(PathNode, PathNode), createPutCommand(PathNode, PathNode), createRemoveCommand(Path)

removeNode

public NodeType removeNode(Path path)

Remove this node and its descendants from the workspace. This method should be overridden by writable path workspace implementations that use the default PathWorkspace.ChangeCommand implementations.

Parameters:

path - the path to the node to be removed; may not be null

Returns:

the previous node state, or null if the node does not exist in this workspace

Throws:

UnsupportedOperationException - by default, subclasses should override this method so that this exception is not thrown

See Also:

createMoveCommand(PathNode, PathNode), createPutCommand(PathNode, PathNode), createRemoveCommand(Path)

removeAll

public void removeAll()

Remove all of the nodes in this workspace, and make sure there is a single root node with no properties and no children.

toString

public String toString()

Overrides:

toString in class Object

See Also:

Object.toString()

hasNodeCache

public boolean hasNodeCache()

Indicates whether this workspace has a node cache. This method should return if the implementation is wired for cache support, even if it happens to be supporting a trivial implementation like NoCachePolicy.

Specified by:

hasNodeCache in interface Workspace

Returns:

true if this workspace has a node cache

See Also:

Workspace.hasNodeCache()

commit

public void commit(List<PathWorkspace.ChangeCommand<NodeType>> commands)

Successively (and in order) apply the changes from the list of pending commands

All validation for each of the objects (including validation of resource availability in the underlying persistent store) should be performed prior to invoking this method.

Parameters:

commands - the list of commands to apply

createPutCommand

public PathWorkspace.ChangeCommand<NodeType> createPutCommand(NodeType oldNode,
                                                              NodeType node)

Create a change command for the required update to the given node

Parameters:

oldNode - the prior version of the node; may be null if this is a new node

node - the new version of the node; may not be null

Returns:

a PathWorkspace.ChangeCommand instance that reflects the changes to the node

See Also:

commit(List)

createRemoveCommand

public PathWorkspace.ChangeCommand<NodeType> createRemoveCommand(Path path)

Create a change command for the removal of the given node and its descendants

Parameters:

path - the path to the node at the root of the branch to be removed; may not be null

Returns:

a PathWorkspace.ChangeCommand instance that reflects the changes to the node

See Also:

createPutCommand(PathNode, PathNode), commit(List)

createMoveCommand

public PathWorkspace.ChangeCommand<NodeType> createMoveCommand(NodeType source,
                                                               NodeType target)

Create a change command that represents the movement of a node. The movement record will only reflect the changes to the node's name and/or parent. Changes to the node's properties or children should be ignored. A separate put command should be used to reflect these changes.

Parameters:

source - the original version of the node; may not be null

target - the new version of the node; may not be null

Returns:

a PathWorkspace.ChangeCommand instance that reflects the changes to the node

See Also:

createMoveCommand(PathNode, PathNode), commit(List)