在Java中比较列表映射中每个对象的性能

Question

我有一个Java程序，其映射类型为<String, Project>，其中包含所有项目对象，项目的每个对象都包含一个相关流程对象列表，即List<Process>

public class Project {
    private String name;
    private Path path;
    private List<Process> processes;
        \\ getters and setters follow

及

public class Process {
    private String name;
    private String path;
    private String flow;
        \\getters and setters follow

我正在编写一个函数来查找每个Process（跨所有项目）的flow之间的字符串距离（使用JaroWinklerDistance）。我得出了以下结论：

    public void compareAllProcesses(Map<String, Project> projects) {
        Iterator<Project> projIter1 = projects.values().iterator();
        while(projIter1.hasNext()) {
            Project proj1 = projIter1.next();
            Iterator<Process> procIter1 = proj1.getProcesses().iterator();
            while(procIter1.hasNext()) {
                Process proc1 = procIter1.next();
                Iterator<Project> projIter2 = projects.values().iterator();
                while(projIter2.hasNext()) {
                    Project proj2 = projIter2.next();
                    Iterator<Process> procIter2 = proj2.getProcesses().iterator();
                    while(procIter2.hasNext()) {
                        Process proc2 = procIter2.next();
                        //use JaroWinklerDistance to compare proc1.getFlow() with proc2.getFLow()
                    }
                }
            }
        }
    }

有没有一种更有效、更优雅的方法来实现这一点

Answer 1

可能与Stream有关：

projects.values()
        .stream()
        .flatMap(p->p.getProcesses().stream())
        .forEach(proc1 ->  projects.values()
                                   .stream()
                                   .flatMap(p->p.getProcesses().stream())
                                   .forEach(proc2 -> {/*do something with proc1 and proc2*/});

Answer 2

List<Process> allProcesses = projects.values()
    .stream()
    .flatMap(p->p.getProcesses().stream());

for (Process currentProcess : allProcesses) {
    for (Process process : allProcesses) {
        //distance calculation
    }
}

Answer 3

也许加一点糖：

    for (Project proj1: projects.values()) {
        for (Process proc1: proj1.getProcesses()) {
            for(Project proj2: projects.values()) {
                for(Process proc2: proj2.getProcesses()) {
                    //use JaroWinklerDistance to compare proc1.getFlow() with proc2.getFLow()
                }
            }
        }
    }