com.yworks.yfiles.server.tiles.servlet
Class BaseServlet

java.lang.Object
  javax.servlet.GenericServlet
      javax.servlet.http.HttpServlet
          com.yworks.yfiles.server.tiles.servlet.BaseServlet

All Implemented Interfaces:

Serializable, Servlet, ServletConfig

Direct Known Subclasses:

InfoServlet, LayoutServlet, LoaderServlet, QueryServlet, TileServlet, TreeCollapserServlet, UpdateServlet

public abstract class BaseServlet
extends HttpServlet

This is an abstract base class for the servlets in the yFiles AJAX servlet package. It provides some utilities for subclasses. These are

• caching graphs
• handling IDs of graph elements
• assigning and querying URLs and descriptions registered at graph nodes.

See Also:

cacheGraph(HttpSession,String,Graph2D), getId(Graph2D, Node), getNodeURL(Graph2D, Node), Serialized Form

Constructor Summary

BaseServlet()


Method Summary

protected static String[]	cachedGraphs(HttpSession session) returns the names of the cached graphs for the given session.
protected static void	cacheGraph(HttpSession session, String graphName, Graph2D graph) caches the given graph for the given name in the given session.
protected void	doGet(HttpServletRequest request, HttpServletResponse response) calls handleGetRequest(HttpServletRequest,HttpServletResponse).
protected void	doPost(HttpServletRequest request, HttpServletResponse response) calls handlePostRequest(HttpServletRequest,HttpServletResponse).
static String	getEdgeDescription(Graph2D graph, Edge edge) returns a description for a given edge.
static URL	getEdgeURL(Graph2D graph, Edge edge) returns a URL for a given edge.
static Object	getForId(Graph2D graph, String id) returns a graph element (node, edge, node label or edge label) for a given graph and an id or null, if not found.
protected static Graph2D	getGraph(HttpSession session, String graphName) returns the graph cached for the given session and name or null, if not found.
protected static Rectangle	getGraphBounds(HttpSession session, String graphName) returns the bounds of the cached graph for the given name and session or null, if not found.
static String	getId(Graph2D graph, Edge e) returns a unique ID for the given edge of the given graph.
static String	getId(Graph2D graph, EdgeLabel el) returns a unique ID for the given edge label of the given graph.
static String	getId(Graph2D graph, Node n) returns a unique ID for the given node of the given graph.
static String	getId(Graph2D graph, NodeLabel nl) returns a unique ID for the given node label of the given graph.
static String	getNodeDescription(Graph2D graph, Node node) returns a description for a given node.
static URL	getNodeURL(Graph2D graph, Node node) returns a URL for a given node.
protected static PrintWriter	getWriter(HttpServletResponse response) returns a PrintWriter for the given response with content type "text/json-comment-filtered".
protected void	handleGetRequest(HttpServletRequest request, HttpServletResponse response) handles GET requests.
protected void	handlePostRequest(HttpServletRequest request, HttpServletResponse response) handles POST requests.
static boolean	hasDescriptions(Graph2D graph) returns true, if there is a data provider for descriptions for the given graph.
static boolean	hasURLs(Graph2D graph) returns true, if there is a data provider for URLs for the given graph.
void	init() calls initialize().
void	initialize() is called for initializing the servlet.
protected static Graph2D	newGraph() returns a new empty graph which already has a hierarchy manager.
static void	setEdgeDescription(Graph2D graph, Edge edge, String desc) sets the description for a given edge.
static void	setEdgeURL(Graph2D graph, Edge edge, String urlString) sets the URL for a given edge.
static void	setNodeDescription(Graph2D graph, Node node, String desc) sets the description for a given node.
static void	setNodeURL(Graph2D graph, Node node, String urlString) sets the URL for a given node.
protected static void	uncacheGraph(HttpSession session, String graphName) removes the graph cached for the given name from the cache for the given session.
protected static void	writeWorldBounds(String graphName, HttpServletRequest request, HttpServletResponse response) writes the world bounds of the graph with the given name cached for the session of the given request to the given response in JSON format.

Methods inherited from class javax.servlet.http.HttpServlet

doDelete, doHead, doOptions, doPut, doTrace, getLastModified, service, service

Methods inherited from class javax.servlet.GenericServlet

destroy, getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, log, log

Methods inherited from class java.lang.Object

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

Constructor Detail

BaseServlet

public BaseServlet()

Method Detail

init

public final void init()
                throws ServletException

calls initialize().

Overrides:

init in class GenericServlet

Throws:

ServletException

initialize

public void initialize()
                throws ServletException

is called for initializing the servlet. Subclasses can customize this method. Note that init() is final.

Throws:

ServletException - if servlet related problems occur

doPost

protected final void doPost(HttpServletRequest request,
                            HttpServletResponse response)
                     throws ServletException,
                            IOException

calls handlePostRequest(HttpServletRequest,HttpServletResponse).

Overrides:

doPost in class HttpServlet

Parameters:

request - the request

response - the response

Throws:

ServletException

IOException

handlePostRequest

protected void handlePostRequest(HttpServletRequest request,
                                 HttpServletResponse response)
                          throws ServletException,
                                 IOException

handles POST requests. This is an empty method for BaseServlet. Subclasses should redefine this method, if necessary. Note that doPost(HttpServletRequest,HttpServletResponse) is final.

Parameters:

request - the request from a client

response - the response to be sent to the client

Throws:

IOException - if I/O problems occur

ServletException - if servlet related problems occur

doGet

protected final void doGet(HttpServletRequest request,
                           HttpServletResponse response)
                    throws ServletException,
                           IOException

calls handleGetRequest(HttpServletRequest,HttpServletResponse).

Overrides:

doGet in class HttpServlet

Parameters:

request - the request

response - the response

Throws:

ServletException

IOException

handleGetRequest

protected void handleGetRequest(HttpServletRequest request,
                                HttpServletResponse response)
                         throws ServletException,
                                IOException

handles GET requests. This is an empty method for BaseServlet. Subclasses should redefine this method, if necessary. Note that doGet(HttpServletRequest,HttpServletResponse) is final.

Parameters:

request - the request from a client

response - the response to be sent to the client

Throws:

IOException - if I/O problems occur

ServletException - if servlet related problems occur

getWriter

protected static PrintWriter getWriter(HttpServletResponse response)
                                throws IOException

returns a PrintWriter for the given response with content type "text/json-comment-filtered".

Parameters:

response - the given response

Returns:

a "text/json-comment-filtered" writer

Throws:

IOException - if the writer cannot be obtained

writeWorldBounds

protected static void writeWorldBounds(String graphName,
                                       HttpServletRequest request,
                                       HttpServletResponse response)
                                throws IOException

writes the world bounds of the graph with the given name cached for the session of the given request to the given response in JSON format.

Parameters:

graphName - the name of the graph

request - a servlet request

response - the response for the request

Throws:

IOException - for problems writing the response

getForId

public static Object getForId(Graph2D graph,
                              String id)

returns a graph element (node, edge, node label or edge label) for a given graph and an id or null, if not found.

Parameters:

graph - the graph

id - the id of the graph element

Returns:

the node, edge, node label or edge label belonging to the given graph with the index equal to the given id or null

getId

public static String getId(Graph2D graph,
                           Node n)

returns a unique ID for the given node of the given graph.

Parameters:

graph - the graph

n - the node

Returns:

a unique ID

See Also:

getId(Graph2D, NodeLabel), getId(Graph2D, Edge)

getId

public static String getId(Graph2D graph,
                           NodeLabel nl)

returns a unique ID for the given node label of the given graph.

Parameters:

graph - the graph

nl - the node label

Returns:

a unique ID

See Also:

getId(Graph2D, Node), getId(Graph2D, Edge)

getId

public static String getId(Graph2D graph,
                           Edge e)

returns a unique ID for the given edge of the given graph.

Parameters:

graph - the graph

e - the edge

Returns:

a unique ID

See Also:

getId(Graph2D, EdgeLabel), getId(Graph2D, Node)

getId

public static String getId(Graph2D graph,
                           EdgeLabel el)

returns a unique ID for the given edge label of the given graph.

Parameters:

graph - the graph

el - the edge label

Returns:

a unique ID

See Also:

getId(Graph2D, Edge), getId(Graph2D, Node)

hasURLs

public static boolean hasURLs(Graph2D graph)

returns true, if there is a data provider for URLs for the given graph.

Parameters:

graph - the given graph

Returns:

true, if there is a data provider for URLs

See Also:

hasDescriptions(Graph2D), getNodeURL(Graph2D, Node), getEdgeURL(Graph2D, Edge)

getNodeURL

public static URL getNodeURL(Graph2D graph,
                             Node node)

returns a URL for a given node.

Parameters:

graph - the graph, the node belongs to

node - the given node

Returns:

a URL or null

See Also:

hasURLs(Graph2D), setNodeURL(Graph2D, Node, String)

setNodeURL

public static void setNodeURL(Graph2D graph,
                              Node node,
                              String urlString)

sets the URL for a given node.

Parameters:

graph - the graph, the node belongs to

node - the given node

urlString - the URL to set

See Also:

hasURLs(Graph2D), getNodeURL(Graph2D, Node)

getEdgeURL

public static URL getEdgeURL(Graph2D graph,
                             Edge edge)

returns a URL for a given edge.

Parameters:

graph - the graph, the edge belongs to

edge - the given edge

Returns:

a URL or null

See Also:

hasURLs(Graph2D), setEdgeURL(Graph2D, Edge, String)

setEdgeURL

public static void setEdgeURL(Graph2D graph,
                              Edge edge,
                              String urlString)

sets the URL for a given edge.

Parameters:

graph - the graph, the node belongs to

edge - the given edge

urlString - the URL to set

See Also:

hasURLs(Graph2D), getEdgeURL(Graph2D, Edge)

hasDescriptions

public static boolean hasDescriptions(Graph2D graph)

returns true, if there is a data provider for descriptions for the given graph.

Parameters:

graph - the given graph

Returns:

true, if there is a data provider for descriptions

See Also:

hasURLs(Graph2D), getNodeDescription(Graph2D, Node), getEdgeDescription(Graph2D, Edge)

getNodeDescription

public static String getNodeDescription(Graph2D graph,
                                        Node node)

returns a description for a given node.

Parameters:

graph - the graph, the node belongs to

node - the given node

Returns:

a description or null

See Also:

hasDescriptions(Graph2D), setNodeDescription(Graph2D, Node, String)

setNodeDescription

public static void setNodeDescription(Graph2D graph,
                                      Node node,
                                      String desc)

sets the description for a given node.

Parameters:

graph - the graph, the node belongs to

node - the given node

desc - the description to be set

See Also:

hasDescriptions(Graph2D), getNodeDescription(Graph2D, Node)

getEdgeDescription

public static String getEdgeDescription(Graph2D graph,
                                        Edge edge)

returns a description for a given edge.

Parameters:

graph - the graph, the edge belongs to

edge - the given edge

Returns:

a description or null

See Also:

hasDescriptions(Graph2D), setEdgeDescription(Graph2D, Edge, String)

setEdgeDescription

public static void setEdgeDescription(Graph2D graph,
                                      Edge edge,
                                      String desc)

sets the description for a given edge.

Parameters:

graph - the graph, the node belongs to

edge - the given edge

desc - the description to be set

See Also:

hasDescriptions(Graph2D), getEdgeDescription(Graph2D, Edge)

cacheGraph

protected static void cacheGraph(HttpSession session,
                                 String graphName,
                                 Graph2D graph)

caches the given graph for the given name in the given session. In addition to the graph itself the world bounds for the graph are cached. Several graphs can be cached, if they are cached using distinct names. If a graph is cached using a name which was already used before, the former cached graph gets overwritten.

Parameters:

session - the session for caching

graphName - the name for the graph

graph - the graph to cache

See Also:

cachedGraphs(HttpSession), uncacheGraph(HttpSession, String), getGraph(HttpSession,String), getGraphBounds(HttpSession,String)

uncacheGraph

protected static void uncacheGraph(HttpSession session,
                                   String graphName)

removes the graph cached for the given name from the cache for the given session.

Parameters:

session - the session

graphName - the name of an entry to be removed from the cache

See Also:

cacheGraph(HttpSession, String, Graph2D), cachedGraphs(HttpSession)

cachedGraphs

protected static String[] cachedGraphs(HttpSession session)

returns the names of the cached graphs for the given session.

Parameters:

session - the session

Returns:

the names of the cached graphs

See Also:

cacheGraph(HttpSession,String,Graph2D), getGraph(HttpSession,String), getGraphBounds(HttpSession,String)

newGraph

protected static Graph2D newGraph()

returns a new empty graph which already has a hierarchy manager.

Returns:

a new graph.

getGraph

protected static Graph2D getGraph(HttpSession session,
                                  String graphName)

returns the graph cached for the given session and name or null, if not found.

Parameters:

session - the session

graphName - the name of the graph

Returns:

the cached graph or null

See Also:

cacheGraph(HttpSession,String,Graph2D), getGraphBounds(HttpSession,String)

getGraphBounds

protected static Rectangle getGraphBounds(HttpSession session,
                                          String graphName)

returns the bounds of the cached graph for the given name and session or null, if not found.

Parameters:

session - the session

graphName - the name of the graph

Returns:

the bounds of the cached graph or null

See Also:

cacheGraph(HttpSession,String,Graph2D), getGraph(HttpSession,String)