Common use of Installation and Usage Clause in Contracts

Installation and Usage. ‌ The latest version of the SPL framework can be obtained from ▇▇▇▇://▇▇▇▇▇▇.▇▇▇/ vhotspur/spl-java. The source code is distributed with Apache Ant build.xml, which al- lows building the entire package and running unit tests. The framework provides a JVM agent, which can can evaluate an SPL formula with modular data sources [BBH+12]. The framework can be used in two modes. In one, SPL acts as an external mechanism controlling the application adaptation. In the other, adaptation rules are contained in the business logic of the application. When SPL is used as an external mechanism, the source code of the application does not need to be modified. As a matter of fact, source code is not needed at all and even the bytecode is modified at run-time only. However, the application itself must expose interfaces for run-time configuration changes. When SPL is incorporated into the application itself, the rules for adaptation are part of the busi- ness logic. This can provide fine-grained performance tuning, however, source code modification are necessary. This is illustrated in the example below. An SPL demonstration example is provided together with the source code. The example shows a monitoring application that adjusts the output quality to reflect load – it draws a graph that normally contains a data point for each hour, however, under high system load only a data point for each day is used – the output is still useful but processing time is reduced. See Figure 12 for an example. Figure 12: Graphs of different quality provided for different monitoring application load. The demo is available in the src/demo-java folder, in the imagequality package, and can be started through the run-demo-imagequality Ant target of the framework build file. The demo uses the HTTP server provided by JVM to respond to requests on port 8888. We used the Pylot performance tool3 to roughly evaluate the advantage of the performance adapta- tion – with no adaptation, the demo could handle 33 requests per second and 95 % of requests finished in 3 seconds, whereas with adaptation, the demo handled 44 requests per second and 95% of all re- quests were finished in 2 seconds. The code itself is intentionally simple, serving to illustrate the benefits of adding an external SPL adaptation to an application. 3▇▇▇▇://▇▇▇.▇▇▇▇▇.▇▇▇

Installation and Usage. ‌ The latest version of the SPL framework can be obtained from ▇▇▇▇://▇▇▇▇▇▇.▇▇▇/ vhotspur/spl-java. The source code is distributed with Apache Ant build.xml, which al- lows building the entire package and running unit tests. The framework provides a JVM agent, which can can evaluate an SPL formula with modular data sources [BBH+12]. The framework can be used in two modes. In one, SPL acts as an external mechanism controlling the application adaptation. In the other, adaptation rules are contained in the business logic of the application. When SPL is used as an external mechanism, the source code of the application does not need to be modified. As a matter of fact, source code is not needed at all and even the bytecode is modified at run-time only. However, the application itself must expose interfaces for run-time configuration changes. When SPL is incorporated into the application itself, the rules for adaptation are part of the busi- ness logic. This can provide fine-grained performance tuning, however, source code modification are necessary. This is illustrated in the example below. An SPL demonstration example is provided together with the source code. The example shows a monitoring application that adjusts the output quality to reflect load – it draws a graph that normally contains a data point for each hour, however, under high system load only a data point for each day is used – the output is still useful but processing time is reduced. See Figure 12 19 for an example. Figure 1219: Graphs of different quality provided for different monitoring application load. The demo is available in the src/demo-java folder, in the imagequality package, and can be started through the run-demo-imagequality Ant target of the framework build file. The demo uses the HTTP server provided by JVM to respond to requests on port 8888. We used the Pylot performance tool3 tool5 to roughly evaluate the advantage of the performance adapta- tion – with no adaptation, the demo could handle 33 requests per second and 95 % of requests finished in 3 seconds, whereas with adaptation, the demo handled 44 requests per second and 95% of all re- quests were finished in 2 seconds. The code itself is intentionally simple, serving to illustrate the benefits of adding an external SPL adaptation to an application. 35▇▇▇▇://▇▇▇.▇▇▇▇▇.▇▇▇