本文整理了Java中java.util.List.isEmpty()方法的一些代码示例，展示了List.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。List.isEmpty()方法的具体详情如下：
包路径：java.util.List
类名称：List
方法名：isEmpty

List.isEmpty介绍

[英]Returns whether this List contains no elements.
[中]返回此列表是否不包含任何元素。

代码示例

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

private Node getParent() {
  if (!this.elements.isEmpty()) {
    return this.elements.get(this.elements.size() - 1);
  }
  else {
    return this.node;
  }
}

代码示例来源：origin: square/okhttp

public Builder removePathSegment(int index) {
 encodedPathSegments.remove(index);
 if (encodedPathSegments.isEmpty()) {
  encodedPathSegments.add(""); // Always leave at least one '/'.
 }
 return this;
}

代码示例来源：origin: alibaba/druid

public boolean hasBeforeComment() {
  if (attributes == null) {
    return false;
  }
  List<String> comments = (List<String>) attributes.get("format.before_comment");
  if (comments == null) {
    return false;
  }
  
  return !comments.isEmpty();
}

代码示例来源：origin: hankcs/HanLP

public void setPenalty(int i, int j, double penalty)
{
  if (penalty_.isEmpty())
  {
    for (int s = 0; s < node_.size(); s++)
    {
      List<Double> penaltys = Arrays.asList(new Double[ysize_]);
      penalty_.add(penaltys);
    }
  }
  penalty_.get(i).set(j, penalty);
}

代码示例来源：origin: square/okhttp

/**
 * Removes a path segment. When this method returns the last segment is always "", which means
 * the encoded path will have a trailing '/'.
 *
 * <p>Popping "/a/b/c/" yields "/a/b/". In this case the list of path segments goes from ["a",
 * "b", "c", ""] to ["a", "b", ""].
 *
 * <p>Popping "/a/b/c" also yields "/a/b/". The list of path segments goes from ["a", "b", "c"]
 * to ["a", "b", ""].
 */
private void pop() {
 String removed = encodedPathSegments.remove(encodedPathSegments.size() - 1);
 // Make sure the path ends with a '/' by either adding an empty string or clearing a segment.
 if (removed.isEmpty() && !encodedPathSegments.isEmpty()) {
  encodedPathSegments.set(encodedPathSegments.size() - 1, "");
 } else {
  encodedPathSegments.add("");
 }
}

代码示例来源：origin: facebook/litho

private static void removeCompletedStateUpdatesFromMap(
  Map<String, List<StateUpdate>> currentStateUpdates,
  Map<String, List<StateUpdate>> completedStateUpdates,
  String key) {
 List<StateUpdate> completed = completedStateUpdates.get(key);
 List<StateUpdate> current = currentStateUpdates.remove(key);
 if (completed != null && current != null) {
  current.removeAll(completed);
 }
 if (current != null && !current.isEmpty()) {
  currentStateUpdates.put(key, current);
 }
}

代码示例来源：origin: jenkinsci/jenkins

public RenderOnDemandClosure(JellyContext context, String attributesToCapture) {
  List<Script> bodyStack = new ArrayList<Script>();
  for (JellyContext c = context; c!=null; c=c.getParent()) {
    Script script = (Script) c.getVariables().get("org.apache.commons.jelly.body");
    if(script!=null) bodyStack.add(script);
  }
  this.bodyStack = bodyStack.toArray(new Script[bodyStack.size()]);
  assert !bodyStack.isEmpty();    // there must be at least one, which is the direct child of <l:renderOnDemand>
  Map<String,Object> variables = new HashMap<String, Object>();
  for (String v : Util.fixNull(attributesToCapture).split(","))
    variables.put(v.intern(),context.getVariable(v));
  // capture the current base of context for descriptors
  currentDescriptorByNameUrl = Descriptor.getCurrentDescriptorByNameUrl();
  this.variables = PackedMap.of(variables);
  Set<String> _adjuncts = AdjunctsInPage.get().getIncluded();
  this.adjuncts = new String[_adjuncts.size()];
  int i = 0;
  for (String adjunct : _adjuncts) {
    this.adjuncts[i++] = adjunct.intern();
  }
}

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

private static List<Element> prependWithSeparator(List<Element> elements) {
  List<Element> result = new ArrayList<>(elements);
  if (result.isEmpty() || !(result.get(0) instanceof Separator)) {
    result.add(0, SEPARATOR);
  }
  return Collections.unmodifiableList(result);
}

代码示例来源：origin: apache/kafka

public Header[] toArray() {
  return headers.isEmpty() ? Record.EMPTY_HEADERS : headers.toArray(new Header[headers.size()]);
}

代码示例来源：origin: google/guava

public void testAsMapGet() {
 for (K key : sampleKeys()) {
  List<V> expectedValues = new ArrayList<>();
  for (Entry<K, V> entry : getSampleElements()) {
   if (entry.getKey().equals(key)) {
    expectedValues.add(entry.getValue());
   }
  }
  Collection<V> collection = multimap().asMap().get(key);
  if (expectedValues.isEmpty()) {
   assertNull(collection);
  } else {
   assertEqualIgnoringOrder(expectedValues, collection);
  }
 }
}

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

private static Profiles merge(String expression, List<Profiles> elements, @Nullable Operator operator) {
  assertWellFormed(expression, !elements.isEmpty());
  if (elements.size() == 1) {
    return elements.get(0);
  }
  Profiles[] profiles = elements.toArray(new Profiles[0]);
  return (operator == Operator.AND ? and(profiles) : or(profiles));
}

代码示例来源：origin: twosigma/beakerx

public void jobStart(int jobId, List<String> executorIds) {
 activeJobId = jobId;
 if (!jobs.contains(jobId)) {
  jobs.add(jobId);
  stagesPerJob.put(jobId, new ArrayList<Integer>());
 }
 if (!executorIds.isEmpty()) {
  this.executorIds.clear();
  this.executorIds.addAll(executorIds);
 }
}

代码示例来源：origin: apache/incubator-dubbo

@Override
public List<URL> lookup(URL url) {
  List<URL> urls = new ArrayList<>();
  Map<String, List<URL>> notifiedUrls = getNotified().get(url);
  if (notifiedUrls != null && notifiedUrls.size() > 0) {
    for (List<URL> values : notifiedUrls.values()) {
      urls.addAll(values);
  if (urls.isEmpty()) {
    List<URL> cacheUrls = getCacheUrls(url);
    if (CollectionUtils.isNotEmpty(cacheUrls)) {
      urls.addAll(cacheUrls);
  if (urls.isEmpty()) {
    for (URL u : getRegistered()) {
      if (UrlUtils.isMatch(url, u)) {
        urls.add(u);
    for (URL u : getSubscribed().keySet()) {
      if (UrlUtils.isMatch(url, u)) {
        urls.add(u);

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

/**
 * Return all configured {@link MappedInterceptor MappedInterceptors} as an array.
 * @return the array of {@link MappedInterceptor MappedInterceptors}, or {@code null} if none
 */
@Nullable
protected final MappedInterceptor[] getMappedInterceptors() {
  List<MappedInterceptor> mappedInterceptors = new ArrayList<>(this.adaptedInterceptors.size());
  for (HandlerInterceptor interceptor : this.adaptedInterceptors) {
    if (interceptor instanceof MappedInterceptor) {
      mappedInterceptors.add((MappedInterceptor) interceptor);
    }
  }
  return (!mappedInterceptors.isEmpty() ? mappedInterceptors.toArray(new MappedInterceptor[0]) : null);
}

代码示例来源：origin: neo4j/neo4j

@Deprecated
@Override
public Map<String,List<String>> getExensionsFor( Class<?> type )
{
  Map<String,List<String>> result = new HashMap<>();
  for ( Map.Entry<String,ServerExtender> extension : extensions.entrySet() )
  {
    List<String> methods = new ArrayList<>();
    for ( PluginPoint method : extension.getValue()
        .getExtensionsFor( type ) )
    {
      methods.add( method.name() );
    }
    if ( !methods.isEmpty() )
    {
      result.put( extension.getKey(), methods );
    }
  }
  return result;
}

代码示例来源：origin: google/guava

public static void assertContainsAllOf(Iterable<?> actual, Object... expected) {
 List<Object> expectedList = new ArrayList<>();
 expectedList.addAll(Arrays.asList(expected));
 for (Object o : actual) {
  expectedList.remove(o);
 }
 if (!expectedList.isEmpty()) {
  Assert.fail("Not true that " + actual + " contains all of " + Arrays.asList(expected));
 }
}

代码示例来源：origin: square/okhttp

/** Returns the remote peer's principle, or null if that peer is anonymous. */
public @Nullable Principal peerPrincipal() {
 return !peerCertificates.isEmpty()
   ? ((X509Certificate) peerCertificates.get(0)).getSubjectX500Principal()
   : null;
}

代码示例来源：origin: google/guava

static <E> List<List<E>> create(List<? extends List<? extends E>> lists) {
 ImmutableList.Builder<List<E>> axesBuilder = new ImmutableList.Builder<>(lists.size());
 for (List<? extends E> list : lists) {
  List<E> copy = ImmutableList.copyOf(list);
  if (copy.isEmpty()) {
   return ImmutableList.of();
  }
  axesBuilder.add(copy);
 }
 return new CartesianList<E>(axesBuilder.build());
}

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

private static Map<Class<? extends Throwable>, Method> initExceptionMappings(Class<?> handlerType) {
  Map<Method, MessageExceptionHandler> methods = MethodIntrospector.selectMethods(handlerType,
      (MethodIntrospector.MetadataLookup<MessageExceptionHandler>) method ->
          AnnotatedElementUtils.findMergedAnnotation(method, MessageExceptionHandler.class));
  Map<Class<? extends Throwable>, Method> result = new HashMap<>();
  for (Map.Entry<Method, MessageExceptionHandler> entry : methods.entrySet()) {
    Method method = entry.getKey();
    List<Class<? extends Throwable>> exceptionTypes = new ArrayList<>();
    exceptionTypes.addAll(Arrays.asList(entry.getValue().value()));
    if (exceptionTypes.isEmpty()) {
      exceptionTypes.addAll(getExceptionsFromMethodSignature(method));
    }
    for (Class<? extends Throwable> exceptionType : exceptionTypes) {
      Method oldMethod = result.put(exceptionType, method);
      if (oldMethod != null && !oldMethod.equals(method)) {
        throw new IllegalStateException("Ambiguous @ExceptionHandler method mapped for [" +
            exceptionType + "]: {" + oldMethod + ", " + method + "}");
      }
    }
  }
  return result;
}

代码示例来源：origin: prestodb/presto

public void add(Object value)
{
  if (_accumulator.isEmpty()) {
    _result.add(value);
  } else {
    CollectionReferring ref = _accumulator.get(_accumulator.size() - 1);
    ref.next.add(value);
  }
}