Wednesday, May 6, 2009

Implementing User Sessions for Crystal Reports Java SDK

If you are submitting requests for batch processing in Crystal Reports via its Java SDK, never login to the server per request. I've seen this implemented and it's just creating an unnecessary overhead. Here are the steps to create a session that would serve multiple requests.

1. Log on to Crystal Report Server

You call the metod CrystalEnterprise.getSessionMgr() which returns you an object of type ISessionMgr. From there call the method of the returned object below which returns an object of type IEnterpriseSession.

logon(String userName, String password, String ceServerName, String secEnterprise);

2. Create Logon Token

The IEnterpriseSession has a method getLogonTokenMgr() that returns ILogonTokenMgr. Call the method below to get the logon token string.

createWCAToken(String clientServerName, int validMinutes, int validNumLogon);

The validMinutes parameter represents how long do you want to maintain the session and the validNumLogon represents how many logons the client can perform in one session within the given valid minutes.

3. Logon to Crystal Server with Token

Call the method below from the class ISessionMgr and pass the logon token string that was previously generated. This returns to you a new IEnterpriseSession that has the token. All transactions will then use this session object until the minutes or log on counts are exhausted.


Of course, somehow this session will expire later on and the client application need to reconnect. The good news is you just have to follow the same steps. On the other hand, if the session is still valid and somehow the application needs to reset the connection, always check for the session if it already expired. If it is, release the token and logoff with the following sequence then proceed to steps 1 through 3 again.

releaseToken(logonTokenString); // called from ILogonTokenMgr
ceSessionWithToken.logoff(); // called from IEnterpriseSession with token
ceSession.logoff(); // called from IEnterpriseSession without token

This approach will be very useful for batch processing. You want to keep the pipe full while the report server is processing. With on demand request report processing, you don't want to keep a session open for a long time.

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