A pure java library which can be used by clients to execute independent methods in parallel. Uses Java 8 Completable Futures, MethodHandles and Generics.
- Uses Apache Velocity template for annotation based code generation.
- Clients can use
@Parallelizableto specify the methods to be parallelized. - Clients can create Signatures just as if calling the method itself.
- Clients can use the library to parallelize methods with different signatures - different return types, method arguments, collections, custom classes etc.
- Clients can also parallelize methods in different classes.
- It can be used in Spring or other DI based projects as well.
- Clients can leverage java concurrency to parallelize method calls without worrying about the implementation.
Example illustrating usage of the API:
Consider a class StudentService.java which provides some methods to query Student data from a database.
List<Integer> getStudentMarks(Long studentId);
List<Student> getStudentsByFirstNames(List<String> firstNames);
String getRandomLastName();
Long findStudentIdByName(String firstName, String lastName);
Student findStudent(String email, Integer age, Boolean isDayScholar);
void printMapValues(Map<String, Integer> bookSeries);Another class SchoolService.java which returns a list of School names via the method
List<String> getSchoolNames();Assuming each method takes 1 second to execute, a client which wants to call all the methods from StudentService and SchoolService will need 7 seconds to get the output of all the sequential service calls.
Using the parallel-execution-engine library, a client can call all the methods simultaneously and get the output in 1 second.
Creating signatures is as simple as :
studentServiceSignatures.add(Signature.build(StudentService_.getStudentMarks(1L)));
studentServiceSignatures.add(Signature.build(StudentService_.getStudentsByFirstNames(Arrays.asList("John","Alice"))));
studentServiceSignatures.add(Signature.build(StudentService_.getRandomLastName()));
studentServiceSignatures.add(Signature.build(StudentService_.findStudentIdByName("Kate", "Williams")));
studentServiceSignatures.add(Signature.build(StudentService_.findStudent("bob@gmail.com", 14, false)));
studentServiceSignatures.add(Signature.build(StudentService_.printMapValues(bookSeries)));
schoolServiceSignatures.add(Signature.build(SchoolService_.getSchoolNames()));And then submit them to the executor to get the combined results:
executionMap.put(studentService, studentServiceSignatures);
executionMap.put(schoolService, schoolServiceSignatures);
List<T> result = ParallelProcessor.genericParallelExecutor(executionMap);StudentService_.java and SchoolService_.java is generated by processing the @Parallelizable annotation at compile time.
Check out the tests in ParallelExecutorTest.java.
Run mvn clean install from the root folder.
Run the main method in examples/Client.java