Hashes

The platform uses hash tables for many purposes. These are in particular hashes for the Agents, the System Agents, the service proxies and the configuration. Since some of them do not fit in the normal unique key - to - value scheme, but can contain more then one value per key it was necessary to create special version of hash tables which can handle more values per key. These are called OTM*Hashtable using the acronym OTM for one - to - many hash tables. There exists two kinds of OTMHashtable, the normal OTMHashtable which can handle strings as keys and the more general OTMObjectHashtable which can handle any objects as you like as key and value. Since these special versions of hash tables are not as optimized for speed as the default Hashtable of the Java class library it is strongly recommended to use them only if it is really necessary.

The Agents residing in the System are archived in the Hashtable agents. As key the AgentID is used and the value is the reference to the Agent. To provide good hash codes for the ID objects and other TAgents proprietary objects there exists a class called HashCode which produces unique hash codes for a string and for a byte array. Since the IDs are normally presented as strings (in the ID objects) or as byte code (in the Name object) these are the two possible cases where hash codes are needed. Internally the hash code is generated by using the hash code generating method of the standard class String of the Java class libraries. This is achieved in the class HashCode by converting the byte array into an String and return its hash code value.

The System Agents are maintained as the Agents in a Hashtable with the AgentID as key and the reference to the System Agent as value. Separate from them exists a OTMHashtable for the services (proxies) they are providing. The proxies hash table uses the string of the name of the interface as key and as value the reference to the proxy. Since more then one System Agent can provide the same interface, like for example the general  
tagents.sysagent.communication.AgentCommIFace, an OTMHashtable is used here to store the proxies.

Places are handled different since they do not fit into the key - value scheme but only have one value. They are stored into a Vector. Since places are still not supported in this version of TAgents, this can be changed in the future.