isEmpty ( )源码实例Demo

java.util.concurrent.ConcurrentNavigableMap#isEmpty ( )源码实例Demo

下面列出了java.util.concurrent.ConcurrentNavigableMap#isEmpty ( ) 实例代码,或者点击链接到github查看源代码,也可以在右侧发表评论。

源代码1 项目: sofa-jraft   文件: MemoryRawKVStore.java
@Override
public void deleteRange(final byte[] startKey, final byte[] endKey, final KVStoreClosure closure) {
    final Timer.Context timeCtx = getTimeContext("DELETE_RANGE");
    try {
        final ConcurrentNavigableMap<byte[], byte[]> subMap = this.defaultDB.subMap(startKey, endKey);
        if (!subMap.isEmpty()) {
            subMap.clear();
        }
        setSuccess(closure, Boolean.TRUE);
    } catch (final Exception e) {
        LOG.error("Fail to [DELETE_RANGE], ['[{}, {})'], {}.", BytesUtil.toHex(startKey), BytesUtil.toHex(endKey),
            StackTraceUtil.stackTrace(e));
        setCriticalError(closure, "Fail to [DELETE_RANGE]", e);
    } finally {
        timeCtx.stop();
    }
}
 
/**
 * Remove implementation mapping for the given adapter type.
 * @param adapterTypeName Adapter type name
 * @param implTypeName Implementation type name
 */
public void remove(String adapterTypeName, String implTypeName) {
    String key = adapterTypeName;
    if (StringUtils.equals(adapterTypeName, implTypeName)) {
        modelClasses.remove(key);
    }
    else {
        // although we already use a ConcurrentMap synchronize explicitly because we apply non-atomic operations on it
        synchronized (adapterImplementations) {
            ConcurrentNavigableMap<String,ModelClass<?>> implementations = adapterImplementations.get(key);
            if (implementations != null) {
                implementations.remove(implTypeName);
                if (implementations.isEmpty()) {
                    adapterImplementations.remove(key);
                }
            }
        }
    }
}
 
/**
 * @param adapterType the type to check
 * @return {@code true} in case the given type is a model (may be with a different adapter class)
 */
@SuppressWarnings("unchecked")
public <ModelType> boolean isModelClass(Class<ModelType> adapterType) {
    String key = adapterType.getName();

    // lookup in cache for models without adapter classes
    ModelClass<ModelType> modelClass = (ModelClass<ModelType>)modelClasses.get(key);
    if (modelClass!=null) {
        return true;
    }

    // not found? look in cache with adapter classes
    ConcurrentNavigableMap<String,ModelClass<?>> implementations = adapterImplementations.get(key);
    if (implementations==null || implementations.isEmpty()) {
        return false;
    }
    return true;
}
 
@Override
public Optional<ServerAddress> resolveByUuid(UUID uuid) {
  Assert.notNull(uuid);
  if (circle.isEmpty()) {
    return Optional.empty();
  }
  Long hash = hashFunction.newHasher().putLong(uuid.getMostSignificantBits()).putLong(uuid.getLeastSignificantBits())
      .hash().asLong();
  if (!circle.containsKey(hash)) {
    ConcurrentNavigableMap<Long, ServerInstance> tailMap = circle.tailMap(hash);
    hash = tailMap.isEmpty() ? circle.firstKey() : tailMap.firstKey();
  }
  ServerInstance result = circle.get(hash);
  if (!currentServer.equals(result)) {
    return Optional.of(result.getServerAddress());
  } else {
    return Optional.empty();
  }
}
 
源代码5 项目: incubator-retired-blur   文件: DeepPagingCache.java
public DeepPageContainer lookup(DeepPageKey key, int skipTo) {
  LOG.debug("Looking up DeepPageContainer for skipTo [{0}] with key hashcode [{1}] and key [{2}]", skipTo,
      key.hashCode(), key);
  DeepPageKeyPlusPosition k = new DeepPageKeyPlusPosition(skipTo, key);
  DeepPageContainer deepPageContainer = _lruCache.get(k);
  if (deepPageContainer != null) {
    _hits.mark();
    return deepPageContainer;
  }

  ConcurrentNavigableMap<DeepPageKeyPlusPosition, DeepPageContainer> headMap = _positionCache.headMap(k, true);
  if (headMap == null || headMap.isEmpty()) {
    _misses.mark();
    return null;
  }
  Entry<DeepPageKeyPlusPosition, DeepPageContainer> firstEntry = headMap.lastEntry();
  DeepPageKeyPlusPosition dpkpp = firstEntry.getKey();
  if (dpkpp._deepPageKey.equals(key)) {
    _hits.mark();
    return firstEntry.getValue();
  }
  _misses.mark();
  return null;
}
 
源代码6 项目: sofa-jraft   文件: MemoryRawKVStore.java
@Override
public byte[] jumpOver(final byte[] startKey, final long distance) {
    final Timer.Context timeCtx = getTimeContext("JUMP_OVER");
    try {
        final byte[] realStartKey = BytesUtil.nullToEmpty(startKey);
        final ConcurrentNavigableMap<byte[], byte[]> tailMap = this.defaultDB.tailMap(realStartKey);
        if (tailMap.isEmpty()) {
            return null;
        }
        long approximateKeys = 0;
        byte[] lastKey = null;
        for (final byte[] key : tailMap.keySet()) {
            lastKey = key;
            if (++approximateKeys >= distance) {
                break;
            }
        }
        if (lastKey == null) {
            return null;
        }
        final byte[] endKey = new byte[lastKey.length];
        System.arraycopy(lastKey, 0, endKey, 0, lastKey.length);
        return endKey;
    } finally {
        timeCtx.stop();
    }
}
 
/**
 * Lookup the best-matching implementation for the given adapter type by enquiring the {@link ImplementationPicker} services.
 * @param adapterType Adapter type
 * @param adaptable Adaptable for reference
 * @return Implementation type or null if none detected
 */
@SuppressWarnings("unchecked")
public <ModelType> ModelClass<ModelType> lookup(Class<ModelType> adapterType, Object adaptable) {
    String key = adapterType.getName();

    // lookup in cache for models without adapter classes
    ModelClass<ModelType> modelClass = (ModelClass<ModelType>)modelClasses.get(key);
    if (modelClass!=null) {
        return modelClass;
    }

    // not found? look in cache with adapter classes
    ConcurrentNavigableMap<String,ModelClass<?>> implementations = adapterImplementations.get(key);
    if (implementations==null || implementations.isEmpty()) {
        return null;
    }
    Collection<ModelClass<?>> implementationsCollection = implementations.values();
    ModelClass<?>[] implementationWrappersArray = implementationsCollection.toArray(new ModelClass<?>[implementationsCollection.size()]);

    // prepare array for implementation picker
    Class<?>[] implementationsArray = new Class<?>[implementationsCollection.size()];
    for (int i=0; i<implementationWrappersArray.length; i++) {
        implementationsArray[i] = implementationWrappersArray[i].getType();
    }

    for (ImplementationPicker picker : this.sortedImplementationPickers) {
        Class<?> implementation = picker.pick(adapterType, implementationsArray, adaptable);
        if (implementation != null) {
            for (int i=0; i<implementationWrappersArray.length; i++) {
                if (implementation==implementationWrappersArray[i].getType()) {
                    return (ModelClass<ModelType>)implementationWrappersArray[i];
                }
            }
        }
    }

    return null;
}
 
源代码8 项目: hbase   文件: MetaRegionLocationCache.java
/**
 * @return Optional list of HRegionLocations for meta replica(s), null if the cache is empty.
 *
 */
public Optional<List<HRegionLocation>> getMetaRegionLocations() {
  ConcurrentNavigableMap<Integer, HRegionLocation> snapshot =
      cachedMetaLocations.tailMap(cachedMetaLocations.firstKey());
  if (snapshot.isEmpty()) {
    // This could be possible if the master has not successfully initialized yet or meta region
    // is stuck in some weird state.
    return Optional.empty();
  }
  List<HRegionLocation> result = new ArrayList<>();
  // Explicitly iterate instead of new ArrayList<>(snapshot.values()) because the underlying
  // ArrayValueCollection does not implement toArray().
  snapshot.values().forEach(location -> result.add(location));
  return Optional.of(result);
}