java.util.Collection.isEmpty()方法的使用及代码示例

x33g5p2x  于2022-01-16 转载在 其他  
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本文整理了Java中java.util.Collection.isEmpty()方法的一些代码示例，展示了Collection.isEmpty()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。Collection.isEmpty()方法的具体详情如下：
包路径：java.util.Collection
类名称：Collection
方法名：isEmpty

Collection.isEmpty介绍

[英]Returns if this Collection contains no elements.
[中]如果此集合不包含元素，则返回。

代码示例

代码示例来源：origin: google/guava

  1. private static boolean isEmpty(Iterable<?> iterable) {
  2.  return iterable instanceof Collection
  3.    ? ((Collection<?>) iterable).isEmpty()
  4.    : !iterable.iterator().hasNext();
  5. }

代码示例来源：origin: google/guava

  1. /** Used during deserialization only. */
  2. final void setMap(Map<K, Collection<V>> map) {
  3.  this.map = map;
  4.  totalSize = 0;
  5.  for (Collection<V> values : map.values()) {
  6.   checkArgument(!values.isEmpty());
  7.   totalSize += values.size();
  8.  }
  9. }

代码示例来源：origin: spring-projects/spring-framework

  1. private String style(Collection<?> value) {
  2.   StringBuilder result = new StringBuilder(value.size() * 8 + 16);
  3.   result.append(getCollectionTypeString(value)).append('[');
  4.   for (Iterator<?> i = value.iterator(); i.hasNext();) {
  5.     result.append(style(i.next()));
  6.     if (i.hasNext()) {
  7.       result.append(',').append(' ');
  8.     }
  9.   }
  10.   if (value.isEmpty()) {
  11.     result.append(EMPTY);
  12.   }
  13.   result.append("]");
  14.   return result.toString();
  15. }

代码示例来源：origin: redisson/redisson

  1. @Override
  2. public RFuture<Boolean> addAllAsync(Collection<? extends String> c) {
  3.   if (c.isEmpty()) {
  4.     return RedissonPromise.newSucceededFuture(false);
  5.   }
  6.   List<Object> params = new ArrayList<Object>(2*c.size());
  7.   params.add(getName());
  8.   for (Object param : c) {
  9.     params.add(0);
  10.     params.add(param);
  11.   }
  12.   return commandExecutor.writeAsync(getName(), StringCodec.INSTANCE, RedisCommands.ZADD_BOOL_RAW, params.toArray());
  13. }

代码示例来源：origin: apache/incubator-shardingsphere

  1. RoutingResult result = new RoutingResult();
  2. if (shardingRule.isAllBroadcastTables(logicTables)) {
  3.   List<RoutingTable> routingTables = new ArrayList<>(logicTables.size());
  4.   for (String each : logicTables) {
  5.     routingTables.add(new RoutingTable(each, each));
  6.   result.getTableUnits().getTableUnits().add(tableUnit);
  7. } else if (logicTables.isEmpty()) {
  8.   result.getTableUnits().getTableUnits().add(new TableUnit(shardingRule.getShardingDataSourceNames().getRandomDataSourceName()));
  9. } else if (1 == logicTables.size()) {
  10.   String logicTableName = logicTables.iterator().next();
  11.   DataNode dataNode = shardingRule.getDataNode(logicTableName);
  12.   TableUnit tableUnit = new TableUnit(dataNode.getDataSourceName());
  13.   tableUnit.getRoutingTables().add(new RoutingTable(logicTableName, dataNode.getTableName()));
  14.   result.getTableUnits().getTableUnits().add(tableUnit);
  15. } else {
  16.   List<RoutingTable> routingTables = new ArrayList<>(logicTables.size());
  17.   Set<String> availableDatasourceNames = null;
  18.   boolean first = true;
  19.     TableRule tableRule = shardingRule.getTableRule(each);
  20.     DataNode dataNode = tableRule.getActualDataNodes().get(0);
  21.     routingTables.add(new RoutingTable(each, dataNode.getTableName()));
  22.     Set<String> currentDataSourceNames = new HashSet<>(tableRule.getActualDatasourceNames().size());
  23.     for (DataNode eachDataNode : tableRule.getActualDataNodes()) {

代码示例来源：origin: stanfordnlp/CoreNLP

  1. /** Returns the (first) root of this SemanticGraph. */
  2. public IndexedWord getFirstRoot() {
  3.  if (roots.isEmpty())
  4.   throw new RuntimeException("No roots in graph:\n" + this
  5.     + "\nFind where this graph was created and make sure you're adding roots.");
  6.  return roots.iterator().next();
  7. }

代码示例来源：origin: commons-collections/commons-collections

  1. public boolean removeAll(Collection coll) {
  2.   if (parent.isEmpty() || coll.isEmpty()) {
  3.     return false;
  4.   }
  5.   boolean modified = false;
  6.   Iterator it = iterator();
  7.   while (it.hasNext()) {
  8.     if (coll.contains(it.next())) {
  9.       it.remove();
  10.       modified = true;
  11.     }
  12.   }
  13.   return modified;
  14. }

代码示例来源：origin: apache/incubator-shardingsphere

  1. @Override
  2. public RoutingResult route() {
  3.   Collection<RoutingResult> result = new ArrayList<>(logicTables.size());
  4.   Collection<String> bindingTableNames = new TreeSet<>(String.CASE_INSENSITIVE_ORDER);
  5.   for (String each : logicTables) {
  6.     if (tableRule.isPresent()) {
  7.       if (!bindingTableNames.contains(each)) {
  8.         result.add(new StandardRoutingEngine(shardingRule, tableRule.get().getLogicTable(), shardingConditions).route());
  9.   if (result.isEmpty()) {
  10.     throw new ShardingException("Cannot find table rule and default data source with logic tables: '%s'", logicTables);
  11.   if (1 == result.size()) {
  12.     return result.iterator().next();

代码示例来源：origin: apache/shiro

  1. public Collection<V> values() {
  2.   processQueue();
  3.   Collection<K> keys = map.keySet();
  4.   if (keys.isEmpty()) {
  5.     //noinspection unchecked
  6.     return Collections.EMPTY_SET;
  7.   }
  8.   Collection<V> values = new ArrayList<V>(keys.size());
  9.   for (K key : keys) {
  10.     V v = get(key);
  11.     if (v != null) {
  12.       values.add(v);
  13.     }
  14.   }
  15.   return values;
  16. }

代码示例来源：origin: stagemonitor/stagemonitor

  1. private static void initIncludesAndExcludes() {
  2.   CorePlugin corePlugin = Stagemonitor.getPlugin(CorePlugin.class);
  3.   excludeContaining = new ArrayList<String>(corePlugin.getExcludeContaining().size());
  4.   excludeContaining.addAll(corePlugin.getExcludeContaining());
  5.   excludes = new ArrayList<String>(corePlugin.getExcludePackages().size());
  6.   excludes.add("org.stagemonitor");
  7.   excludes.addAll(corePlugin.getExcludePackages());
  8.   includes = new ArrayList<String>(corePlugin.getIncludePackages().size());
  9.   includes.addAll(corePlugin.getIncludePackages());
  10.   if (includes.isEmpty()) {
  11.     logger.warn("No includes for instrumentation configured. Please set the stagemonitor.instrument.include property.");
  12.   }
  13. }

代码示例来源：origin: spring-projects/spring-framework

  1. @Nullable
  2. private Collection<CacheOperation> parseCacheAnnotations(
  3.     DefaultCacheConfig cachingConfig, AnnotatedElement ae, boolean localOnly) {
  4.   Collection<? extends Annotation> anns = (localOnly ?
  5.       AnnotatedElementUtils.getAllMergedAnnotations(ae, CACHE_OPERATION_ANNOTATIONS) :
  6.       AnnotatedElementUtils.findAllMergedAnnotations(ae, CACHE_OPERATION_ANNOTATIONS));
  7.   if (anns.isEmpty()) {
  8.     return null;
  9.   }
  10.   final Collection<CacheOperation> ops = new ArrayList<>(1);
  11.   anns.stream().filter(ann -> ann instanceof Cacheable).forEach(
  12.       ann -> ops.add(parseCacheableAnnotation(ae, cachingConfig, (Cacheable) ann)));
  13.   anns.stream().filter(ann -> ann instanceof CacheEvict).forEach(
  14.       ann -> ops.add(parseEvictAnnotation(ae, cachingConfig, (CacheEvict) ann)));
  15.   anns.stream().filter(ann -> ann instanceof CachePut).forEach(
  16.       ann -> ops.add(parsePutAnnotation(ae, cachingConfig, (CachePut) ann)));
  17.   anns.stream().filter(ann -> ann instanceof Caching).forEach(
  18.       ann -> parseCachingAnnotation(ae, cachingConfig, (Caching) ann, ops));
  19.   return ops;
  20. }

代码示例来源：origin: apache/ignite

  1. /**
  2.  * Gets size of the given collection with provided optional predicates.
  3.  *
  4.  * @param c Collection to size.
  5.  * @param p Optional predicates that filters out elements from count.
  6.  * @param <T> Type of the iterator.
  7.  * @return Number of elements in the collection for which all given predicates
  8.  *      evaluates to {@code true}. If no predicates is provided - all elements are counted.
  9.  */
  10. public static <T> int size(@Nullable Collection<? extends T> c, @Nullable IgnitePredicate<? super T>... p) {
  11.   return c == null || c.isEmpty() ? 0 : isEmpty(p) || isAlwaysTrue(p) ? c.size() : size(c.iterator(), p);
  12. }

代码示例来源：origin: google/guava

  1. @CanIgnoreReturnValue
  2. @Override
  3. public boolean putAll(@Nullable K key, Iterable<? extends V> values) {
  4.  checkNotNull(values);
  5.  // make sure we only call values.iterator() once
  6.  // and we only call get(key) if values is nonempty
  7.  if (values instanceof Collection) {
  8.   Collection<? extends V> valueCollection = (Collection<? extends V>) values;
  9.   return !valueCollection.isEmpty() && get(key).addAll(valueCollection);
  10.  } else {
  11.   Iterator<? extends V> valueItr = values.iterator();
  12.   return valueItr.hasNext() && Iterators.addAll(get(key), valueItr);
  13.  }
  14. }

代码示例来源：origin: apache/ignite

  1. /** {@inheritDoc} */
  2. @Override public GridClientData pinNodes(GridClientNode node, GridClientNode... nodes) throws GridClientException {
  3.   Collection<GridClientNode> pinnedNodes = new ArrayList<>(nodes != null ? nodes.length + 1 : 1);
  4.   if (node != null)
  5.     pinnedNodes.add(node);
  6.   if (nodes != null && nodes.length != 0)
  7.     pinnedNodes.addAll(Arrays.asList(nodes));
  8.   return createProjection(pinnedNodes.isEmpty() ? null : pinnedNodes,
  9.     null, null, new GridClientDataFactory(flags));
  10. }

代码示例来源：origin: google/guava

  1. /** An implementation of {@link Multiset#addAll}. */
  2. static <E> boolean addAllImpl(Multiset<E> self, Collection<? extends E> elements) {
  3.  checkNotNull(self);
  4.  checkNotNull(elements);
  5.  if (elements instanceof Multiset) {
  6.   return addAllImpl(self, cast(elements));
  7.  } else if (elements.isEmpty()) {
  8.   return false;
  9.  } else {
  10.   return Iterators.addAll(self, elements.iterator());
  11.  }
  12. }

代码示例来源：origin: google/guava

  1. boolean removeEntriesIf(Predicate<? super Entry<K, Collection<V>>> predicate) {
  2.  Iterator<Entry<K, Collection<V>>> entryIterator = unfiltered.asMap().entrySet().iterator();
  3.  boolean changed = false;
  4.  while (entryIterator.hasNext()) {
  5.   Entry<K, Collection<V>> entry = entryIterator.next();
  6.   K key = entry.getKey();
  7.   Collection<V> collection = filterCollection(entry.getValue(), new ValuePredicate(key));
  8.   if (!collection.isEmpty() && predicate.apply(Maps.immutableEntry(key, collection))) {
  9.    if (collection.size() == entry.getValue().size()) {
  10.     entryIterator.remove();
  11.    } else {
  12.     collection.clear();
  13.    }
  14.    changed = true;
  15.   }
  16.  }
  17.  return changed;
  18. }

代码示例来源：origin: redisson/redisson

  1. @Override
  2. public RFuture<Boolean> addAllAsync(Collection<? extends String> c) {
  3.   if (c.isEmpty()) {
  4.     return RedissonPromise.newSucceededFuture(false);
  5.   }
  6.   List<Object> params = new ArrayList<Object>(2*c.size());
  7.   params.add(getName());
  8.   for (Object param : c) {
  9.     params.add(0);
  10.     params.add(param);
  11.   }
  12.   return commandExecutor.writeAsync(getName(), StringCodec.INSTANCE, RedisCommands.ZADD_BOOL_RAW, params.toArray());
  13. }

代码示例来源：origin: apache/incubator-shardingsphere

  1. @Override
  2. public final int getTransactionIsolation() throws SQLException {
  3.   if (cachedConnections.values().isEmpty()) {
  4.     return transactionIsolation;
  5.   }
  6.   return cachedConnections.values().iterator().next().getTransactionIsolation();
  7. }

代码示例来源：origin: google/guava

  1. } else if (elements instanceof Collection) {
  2.  Collection<E> collection = (Collection<E>) elements;
  3.  if (collection.isEmpty()) {
  4.   return ImmutableSet.of();
  5.  } else {
  6.  if (itr.hasNext()) {
  7.   EnumSet<E> enumSet = EnumSet.of(itr.next());
  8.   Iterators.addAll(enumSet, itr);
  9.   return ImmutableEnumSet.asImmutable(enumSet);

代码示例来源：origin: apache/incubator-shardingsphere

  1. /**
  2.  * Load proxy configuration.
  3.  *
  4.  * @return proxy configuration
  5.  * @throws IOException IO exception
  6.  */
  7. public ShardingConfiguration load() throws IOException {
  8.   Collection<String> schemaNames = new HashSet<>();
  9.   YamlProxyServerConfiguration serverConfig = loadServerConfiguration(new File(ShardingConfigurationLoader.class.getResource(CONFIG_PATH + SERVER_CONFIG_FILE).getFile()));
  10.   File configPath = new File(ShardingConfigurationLoader.class.getResource(CONFIG_PATH).getFile());
  11.   Collection<YamlProxyRuleConfiguration> ruleConfigurations = new LinkedList<>();
  12.   for (File each : findRuleConfigurationFiles(configPath)) {
  13.     Optional<YamlProxyRuleConfiguration> ruleConfig = loadRuleConfiguration(each, serverConfig);
  14.     if (ruleConfig.isPresent()) {
  15.       Preconditions.checkState(schemaNames.add(ruleConfig.get().getSchemaName()), "Schema name `%s` must unique at all rule configurations.", ruleConfig.get().getSchemaName());
  16.       ruleConfigurations.add(ruleConfig.get());
  17.     }
  18.   }
  19.   Preconditions.checkState(!ruleConfigurations.isEmpty() || null != serverConfig.getOrchestration(), "Can not find any sharding rule configuration file in path `%s`.", configPath.getPath());
  20.   Map<String, YamlProxyRuleConfiguration> ruleConfigurationMap = new HashMap<>(ruleConfigurations.size(), 1);
  21.   for (YamlProxyRuleConfiguration each : ruleConfigurations) {
  22.     ruleConfigurationMap.put(each.getSchemaName(), each);
  23.   }
  24.   return new ShardingConfiguration(serverConfig, ruleConfigurationMap);
  25. }

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