在Java 8中以lambda块同步

Question

Can synchronized be used for some of the code blocks written in lambda expression block. With respect to the following code snippet :

workflowTasks.forEach((workflowTask) -> {
        String taskName = workflowTask.getTaskName();
        if (profileNames.containsKey(taskName) || newSetDuplication.contains(taskName)) {
            errorMessages.append(taskName + ",");
        }
        newSetDuplication.add(taskName);
    });

Answer 1

Of course! Your block of code is logically equivalent to the following, assuming workFlowTask is of the type WorkFlowTask :

for (WorkFlowTask workFlowTask : workFlowTasks) {
    String taskName = workflowTask.getTaskName();

    if (profileNames.containsKey(taskName) || newSetDuplication.contains(taskName)) {
        errorMessages.append(taskName + ",");
    }

    newSetDuplication.add(taskName);
}

Obviously, the synchronized keyword can be used here, although there are many other things to consider before using it, especially within a loop . Your forEach lambda is just syntactic sugar for a Consumer<WorkFlowTask> anyway, which you can also use synchronized with.