本文整理汇总了Java中java.util.concurrent.ConcurrentHashMap.computeIfAbsent方法的典型用法代码示例。如果您正苦于以下问题：Java ConcurrentHashMap.computeIfAbsent方法的具体用法？Java ConcurrentHashMap.computeIfAbsent怎么用？Java ConcurrentHashMap.computeIfAbsent使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类java.util.concurrent.ConcurrentHashMap的用法示例。
在下文中一共展示了ConcurrentHashMap.computeIfAbsent方法的7个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Java代码示例。
示例1: testcomputeIfAbsent_performance
import java.util.concurrent.ConcurrentHashMap; //导入方法依赖的package包/类
/**
* Tests performance of computeIfAbsent when the element is present.
* See JDK-8161372
* ant -Djsr166.tckTestClass=ConcurrentHashMapTest -Djsr166.methodFilter=testcomputeIfAbsent_performance -Djsr166.expensiveTests=true tck
*/
public void testcomputeIfAbsent_performance() {
final int mapSize = 20;
final int iterations = expensiveTests ? (1 << 23) : mapSize * 2;
final int threads = expensiveTests ? 10 : 2;
final ConcurrentHashMap<Integer, Integer> map = new ConcurrentHashMap<>();
for (int i = 0; i < mapSize; i++)
map.put(i, i);
final ExecutorService pool = Executors.newFixedThreadPool(2);
try (PoolCleaner cleaner = cleaner(pool)) {
Runnable r = new CheckedRunnable() {
public void realRun() {
int result = 0;
for (int i = 0; i < iterations; i++)
result += map.computeIfAbsent(i % mapSize, k -> k + k);
if (result == -42) throw new Error();
}};
for (int i = 0; i < threads; i++)
pool.execute(r);
}
}
示例2: addBlankFile
import java.util.concurrent.ConcurrentHashMap; //导入方法依赖的package包/类
public void addBlankFile(BlankFileMessage blankFileMessage) {
int clientId = blankFileMessage.getClientId();
int fileId = blankFileMessage.getFileId();
Client client = clients.get(clientId);
File clientFile = getOrCreateClientFile(fileId, client);
ConcurrentHashMap<Long, Region> clientRegions = clientFile.getRegions();
ConcurrentHashMap<Long, Region> serverRegions = files.get(fileId).getRegions();
byte[] emptyByteArrayRegionSize = new byte[(int) REGION_SIZE];
byte[] slowDigestForWholeEmptyRegion = Base64.getEncoder().encode(emptyByteArrayRegionSize);
for (Region serverRegion : serverRegions.values()) {
long offset = serverRegion.getOffset();
long size = serverRegion.getSize();
Region region = clientRegions.computeIfAbsent(offset, (aLong) ->
new Region(offset, size));
region.setQuickDigest(0);
if(region.getSize() == REGION_SIZE) {
region.setSlowDigest(slowDigestForWholeEmptyRegion);
} else {
byte[] emptyArraySmallerSize = new byte[(int) region.getSize()];
region.setSlowDigest(
Base64.getEncoder()
.encode(emptyArraySmallerSize));
}
}
}
示例3: main
import java.util.concurrent.ConcurrentHashMap; //导入方法依赖的package包/类
public static void main(String[] args) {
ArrayList<String> list = new ArrayList<>(Arrays.asList("I", "love", "you", "too"));
list.removeIf(new Predicate<String>() {
@Override
public boolean test(String s) {
if (s.length() < 2) {
return true;
}
return false;
}
});
list.removeIf(l -> l.length() < 4);
System.out.println(JSON.toJSONString(list));
Date date = new Date();
ConcurrentHashMap concurrentHashMap = new ConcurrentHashMap<>();
concurrentHashMap.put("ds", 1);
concurrentHashMap.computeIfAbsent("fdfd", k -> k.toString());
System.out.println(JSON.toJSONString(concurrentHashMap));
HashMap hashMap = new HashMap<>();
hashMap.put("fd1", 1);
hashMap.put("fd2", 1);
hashMap.put("fd3", 1);
hashMap.put("fd4", "fd");
hashMap.put("fd5", 1);
hashMap.entrySet().stream().forEach(hash -> {
System.out.println(hash.toString());
});
}
示例4: testComputeIfAbsent
import java.util.concurrent.ConcurrentHashMap; //导入方法依赖的package包/类
/**
* computeIfAbsent adds when the given key is not present
*/
public void testComputeIfAbsent() {
ConcurrentHashMap map = map5();
map.computeIfAbsent(six, x -> "Z");
assertTrue(map.containsKey(six));
}
示例5: testComputeIfAbsent3
import java.util.concurrent.ConcurrentHashMap; //导入方法依赖的package包/类
/**
* computeIfAbsent does not add if function returns null
*/
public void testComputeIfAbsent3() {
ConcurrentHashMap map = map5();
map.computeIfAbsent(six, x -> null);
assertFalse(map.containsKey(six));
}
示例6: getClientRegion
import java.util.concurrent.ConcurrentHashMap; //导入方法依赖的package包/类
private Region getClientRegion(int clientId, int fileId, long offset) {
Client client = clients.get(clientId);
File clientFile = getOrCreateClientFile(fileId, client);
Region serverRegion = files.get(fileId).getRegions().get(offset);
ConcurrentHashMap<Long, Region> clientRegions = clientFile.getRegions();
return clientRegions.computeIfAbsent(offset, (aLong) -> new Region(serverRegion.getOffset(), serverRegion.getSize()));
}
示例7: addOperationToHash
import java.util.concurrent.ConcurrentHashMap; //导入方法依赖的package包/类
private void addOperationToHash(ConcurrentHashMap<String, ConcurrentLinkedDeque<Operation>> userHash,
Operation operation) {
ConcurrentLinkedDeque<Operation> opList = userHash.computeIfAbsent(operation.getUser(), user -> new ConcurrentLinkedDeque<>());
opList.add(operation);
}