Handling Exceptions

Each interface has a throws clause that defines a CIM Exception. An exception is an error condition. The CIM Object Manager uses Java exception handling and creates a hierarchy of WBEM-specific exceptions. The CIMException class is the base class for CIM exceptions. All other CIM exception classes extend from the CIMException class.

Each class of CIM exceptions defines a particular type of error condition that API code handles. See Table 3–2 for a description of the CIM exception APIs.

Using the Try/Catch Clauses

The Client API uses standard Java try/catch clauses to handle exceptions. Generally, an application catches exceptions and either takes some corrective action or passes some information about the error to the user.

The CIM rules are not explicitly identified in the CIM specification. In many cases, they are implied by example. In many cases, the error code refers to a general problem, for example, a data type mismatch, but the programmer must figure out what the correct data type is for the data.

Syntactic and Semantic Error Checking

The MOF Compiler (mofc) compiles .mof text files into Java classes (bytecode). The MOF Compiler does syntactical checking of the MOF files. The CIM Object Manager does semantic and syntactical checking because it can be accessed by many different applications.

The MOF file in Example 4–19 defines two classes, A and B. If you compiled this example file, the CIM Object Manager would return a semantic error because only a key can override another key.

Example 4–19 Semantic Error Checking

Class A         \\Define Class A
 {     [Key]
int a;  
}  
Class B:A       \\Class B extends A 
{  [overrides ("c", key (false)) ]
int b;   
}