How To: Applet Communication to a WL Cluster

          Hello,
          I currently have a Java 1.2 applet that has been converted to
          use a WL cluster (it needed fail over and load balancing.)
          The applet communicates with servlets (which in turn communicate
          with stateless EJBs) via an HTTP request. The WL cluster has
          been set-up and works fine. The problem is that I receive a
          SocketPermissions error when trying to connect to the WL cluster.
          I haven't found anything thats says an applet can't be used with
          a cluster, so I'm assuming there is a provision to get around
          the applet security model, but I'm unable to find anything that
          really tells me how. I found one posting that made reference to
          the 'WLS RJVM scheme', but I can't find any material on this
          either.
          Environment Info:
          - Java applet 1.2
          - IE 5.5 (using plug-in)
          - Apache WebServer
          - WL 5.1
          - Applet will be running on a INTRANET
          * Modifying the Java policy file is not an option for us.
          Any help would be greatly appreciated.
          thx
          D.Curtis

The applet, unless it is signed etc., can only communicate with the server
 from which it was downloaded. You should have a single address visible for
 the entire cluster, through WL proxying or via BigIp/Alteon/etc.
 Peace,
 Cameron Purdy
 Tangosol Inc.
 << Tangosol Server: How Weblogic applications are customized >>
 << Download now from http://www.tangosol.com/registration.jsp >>
 "D.Curtis" <[email protected]> wrote in message
 news:[email protected]...
 >
 > Hello,
 >
 > I currently have a Java 1.2 applet that has been converted to
 > use a WL cluster (it needed fail over and load balancing.)
 > The applet communicates with servlets (which in turn communicate
 > with stateless EJBs) via an HTTP request. The WL cluster has
 > been set-up and works fine. The problem is that I receive a
 > SocketPermissions error when trying to connect to the WL cluster.
 > I haven't found anything thats says an applet can't be used with
 > a cluster, so I'm assuming there is a provision to get around
 > the applet security model, but I'm unable to find anything that
 > really tells me how. I found one posting that made reference to
 > the 'WLS RJVM scheme', but I can't find any material on this
 > either.
 >
 > Environment Info:
 > - Java applet 1.2
 > - IE 5.5 (using plug-in)
 > - Apache WebServer
 > - WL 5.1
 > - Applet will be running on a INTRANET
 >
 > * Modifying the Java policy file is not an option for us.
 >
 > Any help would be greatly appreciated.
 >
 > thx
 > D.Curtis

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package com.oreilly.servlet;
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import java.util.*;
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Hi frndz,
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Tell me what happenned ...

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DO NOT REPLY TO SUCH BASIC QUESTION
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Try this example :
Files used :
1). AppletCom.html
2). First.java
3). Second.java
1).AppletCom.html
<HTML>
<BODY bgcolor="#FFFFFF" link="#0000A0" vlink="#000080">
<LI><H2>Inter applet communication Applet</H2>
<applet code=First.class name="theFirst" width=250 height=100></applet>
<applet code=Second.class width=350 height=100></applet>
 
Source First.java Second.java

<HR>
Last updated 8/5/97 Martin Eggenberger
<HR>
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import java.applet.*;
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First applet1=(First)f;
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String str=applet1.getnm(22,25);
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Color cl=applet1.getcc();
setBackground(cl);
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Regards,
Hiten

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Suppose this is related ?

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please explain.

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Theoretically you could get around this by converting the cluster table to a transparent table. You can do this in the SAP dictionary. However, in practice this is almost never a good solution. The table becomes much larger (clusters are compressed) and you lose the advantage that related records are stored close to each other (the main reason for having cluster tables in the first place). Apart from the performance and disk space hit, converting a big cluster table like BSEG to transparent would take extremely long.
In cases where "indexing" of fields of a cluster table is worthwhile, SAP has constructed "indexing tables" around the cluster. For example, around BSEG there are transparent tables like BSIS, BSAS, etc. Other clusters normally do not have this, but that simply means there is no reason for having it. I have worked with the SAP dictionary for over 12 years and I have never met a single case where it was necessary to convert a cluster to transparent.
If you try to select on specific values of a non-transparent field in a cluster without also specifying selections for the primary key, then the database will have to do a serial read of the whole physical cluster (and the ABAP DB interface will have to decompress every single record to extract the fields). The performance of that is monstrous -- maybe that was the reason of your question. However, the solution then is (in the case of BSEG) to query via one of the index tables (where you are free to create secondary indexes since those tables are transparent).

How To: Applet Communication to a WL Cluster

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