import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ForkJoinPool;
public
class ConcurrentHashMap1 {
public static
void main(String[] args) {
System.out.println(
"Parallelism: " + ForkJoinPool.getCommonPoolParallelism());
testForEach();
testSearch();
testReduce();
}
private static
void testReduce() {
ConcurrentHashMap<String, String> map =
new ConcurrentHashMap<>();
map.putIfAbsent(
"foo",
"bar");
map.putIfAbsent(
"han",
"solo");
map.putIfAbsent(
"r2",
"d2");
map.putIfAbsent(
"c3",
"p0");
String reduced = map.reduce
(1, (key, value) -> key + "=" + value,
(s1, s2) -> s1 + ", " + s2);
System.out.println(reduced);
}
private static void testSearch() {
ConcurrentHashMap<String, String> map = new ConcurrentHashMap<>();
map.putIfAbsent("foo", "bar");
map.putIfAbsent("han", "solo");
map.putIfAbsent("r2", "d2");
map.putIfAbsent("c3", "p0");
System.out.println("\nsearch()\n");
String result1 = map.search(1, (key, value) -> {
System.out.println(Thread.currentThread().getName());
if (key.equals("foo") && value.equals("bar")) {
return "foobar";
}
return null;
});
System.out.println(result1);
System.out.println("\nsearchValues()\n");
String result2 = map.searchValues(1, value -> {
System.out.println(Thread.currentThread().getName());
if (value.length() > 3) {
return value;
}
return null;
});
System.out.println(result2);
}
private static void testForEach() {
ConcurrentHashMap<String, String> map = new ConcurrentHashMap<>();
map.putIfAbsent("foo", "bar");
map.putIfAbsent("han", "solo");
map.putIfAbsent("r2", "d2");
map.putIfAbsent("c3", "p0");
map.forEach(1, (key, value) -> System.out.printf("key: %s; value: %s; thread: %s\n", key, value, Thread.currentThread().getName()));
// map.forEach(5, (key, value) -> System.out.printf("key: %s; value: %s; thread: %s\n", key, value, Thread.currentThread().getName()));
System.out.println(map.mappingCount());
}
}
转载于:https://www.cnblogs.com/bilaisheng/p/10210902.html
