de.fhg.igd.atlas.core
Class CookieManager

java.lang.Object
  de.fhg.igd.atlas.core.CookieManager

public class CookieManager

extends Object

Provides all methods needed for the Location Service Protocol (LSP) which deal with cookie generation and storage.

Version:

"$Id: CookieManager.java 1913 2007-08-08 02:41:53Z jpeters $"

Author:

Jan Peters

Field Summary

protected AgentContext	agentContext_ The reference to the agent context (needed to read, update and delete the current and temporary cookie of the agent).
static int	COOKIE_LENGTH The length of a cookie in bytes.
static byte[]	NULL_COOKIE The unique null cookie, which is used to distinguish between Init, Update and Delete register requests within the Location Service Protocol.
static String	PATH_TO_CURRENT_COOKIE The path and filename within the agent resource to store the current cookie.
static String	PATH_TO_TMP_COOKIE The path and filename within the agent resource to store the temporary cookie, which is needed for the backup protocol.
static String	SR_ALG The algorithm used to calculate secure randoms for cookie generation.

Constructor Summary

CookieManager(AgentContext agentContext)
Creates an new instance of this class.

Method Summary

boolean	existsCurrentCookie() Checks if a current cookie is existent.
boolean	existsTmpCookie() Checks if a temporary cookie is existent.
static byte[]	generateCookie() Generates a new cookie of length COOKIE_LENGTH.
protected byte[]	readCookieFromResource(Resource agentResource, String path) Reads a cookie from the given path within the agent resource.
byte[]	readCurrentCookie() Reads the current cookie from the agent resource.
byte[]	readTmpCookie() Reads the temporary cookie from the agent resource.
void	removeCurrentCookie() Removes the current cookie of the agent within the agent resource and the agent context.
void	removeTmpCookie() Removes the temporary cookie of the agent within the agent resource and the agent context.
protected void	writeCookieToResource(Resource agentResource, byte[] cookie, String path) Writes the given cookie to the given path within the agent resource.
void	writeCurrentCookie(byte[] cookie) Writes the given cookie as current cookie to the agent resource and to the agent context.
void	writeTmpCookie(byte[] cookie) Writes the given cookie as temporary cookie to the agent resource and to the agent context.

Methods inherited from class java.lang.Object

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

Field Detail

SR_ALG

public static final String SR_ALG

The algorithm used to calculate secure randoms for cookie generation.

See Also:

Constant Field Values

PATH_TO_CURRENT_COOKIE

public static String PATH_TO_CURRENT_COOKIE

The path and filename within the agent resource to store the current cookie.

PATH_TO_TMP_COOKIE

public static String PATH_TO_TMP_COOKIE

The path and filename within the agent resource to store the temporary cookie, which is needed for the backup protocol.

NULL_COOKIE

public static final byte[] NULL_COOKIE

The unique null cookie, which is used to distinguish between Init, Update and Delete register requests within the Location Service Protocol.

COOKIE_LENGTH

public static final int COOKIE_LENGTH

The length of a cookie in bytes.

See Also:

Constant Field Values

agentContext_

protected AgentContext agentContext_

The reference to the agent context (needed to read, update and delete the current and temporary cookie of the agent).

Constructor Detail

CookieManager

public CookieManager(AgentContext agentContext)

Creates an new instance of this class. The given agentContext is used to obtain the current or temporary cookie directly or from the resource of the agent. If the agent resource is existent it obtains priority concerning the state of the cookies. Only in the case when the agent resource is not valid any more, those cookies are used, which are stored directly within the agents context. This happens, if the agent has migrated and the agent context is still available (when the agent state changes from migrated to invalid)

Parameters:

agentContext - The context of an agent.

Method Detail

generateCookie

public static byte[] generateCookie()
                             throws NoSuchAlgorithmException

Generates a new cookie of length COOKIE_LENGTH.

Returns:

The generated cookie.

Throws:

NoSuchAlgorithmException - if the generation of secure randoms is not supported.

removeCurrentCookie

public void removeCurrentCookie()
                         throws IOException

Removes the current cookie of the agent within the agent resource and the agent context.

Throws:

IOException - if an error occures during access to the agents resource.

removeTmpCookie

public void removeTmpCookie()
                     throws IOException

Removes the temporary cookie of the agent within the agent resource and the agent context.

Throws:

IOException - if an error occures during access to the agents resource.

existsCurrentCookie

public boolean existsCurrentCookie()

Checks if a current cookie is existent. If the agent resource is not valid any more, this method checks whether the current cookie is existent within agent context.

Returns:

true if the current cookie is existent; false otherwise.

existsTmpCookie

public boolean existsTmpCookie()

Checks if a temporary cookie is existent. If the agent resource is not valid any more, this method checks whether the temporary cookie is existent within agent context.

Returns:

true if the temporary cookie is existent; false otherwise.

readCurrentCookie

public byte[] readCurrentCookie()
                         throws IOException

Reads the current cookie from the agent resource. If the agent resource is not valid any more, this method tries to read the current cookie from the agent context.

Returns:

The current cookie of the agent if existent; the NULL_COOKIE otherwise

Throws:

IOException - if an error occures during access to the agents resource.

readTmpCookie

public byte[] readTmpCookie()
                     throws IOException

Reads the temporary cookie from the agent resource. If the agent resource is not valid any more, this method tries to read the temporary cookie from the agent context.

Returns:

The temporary cookie of the agent if existent; the NULL_COOKIE otherwise.

Throws:

IOException - if an error occures during access to the agents resource.

readCookieFromResource

protected byte[] readCookieFromResource(Resource agentResource,
                                        String path)
                                 throws IOException

Reads a cookie from the given path within the agent resource.

Parameters:

path - The path within the agent resource.

Returns:

The cookie, if existent; the NULL_COOKIE otherwise.

Throws:

IOException - if an error occures during access to the agents resource.

writeCurrentCookie

public void writeCurrentCookie(byte[] cookie)
                        throws IOException

Writes the given cookie as current cookie to the agent resource and to the agent context.

Returns:

The cookie.

Throws:

IOException - if an error occures during access to the agents resource.

writeTmpCookie

public void writeTmpCookie(byte[] cookie)
                    throws IOException

Writes the given cookie as temporary cookie to the agent resource and to the agent context.

Returns:

The cookie.

Throws:

IOException - if an error occures during access to the agents resource.

writeCookieToResource

protected void writeCookieToResource(Resource agentResource,
                                     byte[] cookie,
                                     String path)
                              throws IOException

Writes the given cookie to the given path within the agent resource.

Parameters:

path - The path within the agent resource.

Returns:

The cookie.

Throws:

IOException - if an error occures during access to the agents resource.