Patterns for Program Query Optimisation

Operations on data can be classified as either queries or updates. Modern object-oriented program-ming languages require classes/interfaces to support a predefined set of queries. This presents a challenge for software designers, since a fixed interface can severely restrict the opportunities for optimisation. In this paper, we present two common patterns for optimising queries. The first requires specific knowl-edge of which query to optimise beforehand, whilst the latter provides more leeway in this regard. These patterns are commonly occurring in software, and we find numerous instances of them within the Java standard libraries