Prerequisite: In order to understand content of this document please carefully read Indexing structure document first.
Requirements
...
Realization of the index query system is shown in the class diagram below.
Searching the right tree part
...
- is Null
- is not Null
- equals
- not equals
- greater than
- greater or equals than
- less than
- less or equals than
- is in collection
- are all in collection
Since reflection is relatively slow, it was concluded that major performance improvement would be to cache all methods that are invoked. Because of this, IIndexQueryRestirctionProcessor interface is defined, and IndexQuery is simply delegating the checking of all restrictions to the processor.
Need for aggregation
...
Updates in version 1.4
There was a need for a extended indexing query class that will provide the needed functionality for the storage tree queering. Because of that the IStorageIndexQuery was defined with three additional properties that can be specified:
- Exclude IDs - set of the object IDs that will be excluded in the result
- Include IDs - set of objects that will be included in the result
- Only invocations without children - If searching for invocations this flag can be set to specify if the complete objects should be retrieved or their cloned copies without children.
Query providers
The IIndexQueryProvider<E extends IIndexQuery> was introduced, with two implementing classes IndexQueryProvider and StorageIndexQueryProvider. Two problems are solved with providers:
- Ability to get correctly initialized query objects as the Spring prototype bean
- Ability to create the query factories that will define the queries need, with no distinction if the query is of the simple or the storage type.
Query factories
As mentioned above the query factories are able to create the proper indexing query without depending if the returning object is IIndexQuery or IStorageIndexQuery. Since the storage services on the UI have to execute the same queries as the ones on the CMR, just with the IStorageIndexQuery objects, the factories were introduces as the on-place where queries will be defined. Later on Spring will bound a StorageIndexQueryProvider to a factory that is producing queries for the storage services. On the other hand Spring will bound a IndexQueryProvider for factories used in the CMR DAO classes.
Aggregators
Classes that can aggregate one type of data are called Aggregators and all implement the IAggregator<E extends DefaultData> interface. Currently following are available:
- ExceptionDataAggregator
- HttpTimerDataAggregator
- SqlStatementDataAggregator
- TimerDataAggregator
AbstractStorageService class on the UI and AbstractBufferDataDao class provide methods can query the indexed tree with supplied query and optionally the IAggregator, Comparator and element count limit. If all are supplied, the elements retrieved by the query will bi first aggregated, then sorted and at the end result list will be decreased if needed to the limit.