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

Map.isEmpty介绍

[英]Returns whether this map is empty.
[中]返回此映射是否为空。

代码示例

代码示例来源：origin: google/guava

Itr() {
 keyIterator = map.entrySet().iterator();
 key = null;
 collection = null;
 valueIterator = Iterators.emptyModifiableIterator();
}

代码示例来源：origin: skylot/jadx

private void attachSourceLine(int decompiledLine, int sourceLine) {
  if (lineMap.isEmpty()) {
    lineMap = new TreeMap<>();
  }
  lineMap.put(decompiledLine, sourceLine);
}

代码示例来源：origin: google/guava

@VisibleForTesting
static char[][] createReplacementArray(Map<Character, String> map) {
 checkNotNull(map); // GWT specific check (do not optimize)
 if (map.isEmpty()) {
  return EMPTY_REPLACEMENT_ARRAY;
 }
 char max = Collections.max(map.keySet());
 char[][] replacements = new char[max + 1][];
 for (char c : map.keySet()) {
  replacements[c] = map.get(c).toCharArray();
 }
 return replacements;
}

代码示例来源：origin: stanfordnlp/CoreNLP

public Map<String, String> classORRestrictionsAsString(){
 if(classORrestrictions== null || classORrestrictions.isEmpty())
  return null;
 Map<String, String> str = new HashMap<>();
 for(Map.Entry<Class, String> en: classORrestrictions.entrySet()){
   str.put(class2KeyMapping.get(en.getKey()), en.getValue());
 }
 return str;
}

代码示例来源：origin: org.assertj/assertj-core

private static boolean noNonMatchingModifier(Set<String> expectedMethodNames, Map<String, Integer> methodsModifier,
                       Map<String, String> nonMatchingModifiers, int modifier) {
 for (String method : methodsModifier.keySet()) {
  if (expectedMethodNames.contains(method) && (methodsModifier.get(method) & modifier) == 0) {
   nonMatchingModifiers.put(method, Modifier.toString(methodsModifier.get(method)));
  }
 }
 return nonMatchingModifiers.isEmpty();
}

代码示例来源：origin: google/guava

@CanIgnoreReturnValue
private Map<R, V> removeColumn(Object column) {
 Map<R, V> output = new LinkedHashMap<>();
 Iterator<Entry<R, Map<C, V>>> iterator = backingMap.entrySet().iterator();
 while (iterator.hasNext()) {
  Entry<R, Map<C, V>> entry = iterator.next();
  V value = entry.getValue().remove(column);
  if (value != null) {
   output.put(entry.getKey(), value);
   if (entry.getValue().isEmpty()) {
    iterator.remove();
   }
  }
 }
 return output;
}

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

/**
 * Merge a single hint into a map of hints, possibly creating and copying
 * all hints into a new map, or otherwise if the map of hints is empty,
 * creating a new single entry map.
 * @param hints a map of hints to be merge
 * @param hintName the hint name to merge
 * @param hintValue the hint value to merge
 * @return a single map with all hints
 */
public static Map<String, Object> merge(Map<String, Object> hints, String hintName, Object hintValue) {
  if (hints.isEmpty()) {
    return Collections.singletonMap(hintName, hintValue);
  }
  else {
    Map<String, Object> result = new HashMap<>(hints.size() + 1);
    result.putAll(hints);
    result.put(hintName, hintValue);
    return result;
  }
}

代码示例来源：origin: google/guava

public void testAsMapEmpty() {
 Set<String> strings = ImmutableSet.of();
 Map<String, Integer> map = Maps.asMap(strings, LENGTH_FUNCTION);
 assertThat(map.entrySet()).isEmpty();
 assertTrue(map.isEmpty());
 assertNull(map.get("five"));
}

代码示例来源：origin: mpusher/mpush

@Override
public <T> Map<String, T> hgetAll(String key, Class<T> clazz) {
  Map<String, Object> m = (Map) cache.get(key);
  if (m == null || m.isEmpty()) return Collections.emptyMap();
  Map<String, T> result = new HashMap<>();
  for (Map.Entry<String, Object> o : m.entrySet()) {
    result.put(o.getKey(), Jsons.fromJson(String.valueOf(o.getValue()), clazz));
  }
  return result;
}

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

protected void detectResourceHandlers(ApplicationContext appContext) {
  Map<String, SimpleUrlHandlerMapping> beans = appContext.getBeansOfType(SimpleUrlHandlerMapping.class);
  List<SimpleUrlHandlerMapping> mappings = new ArrayList<>(beans.values());
  AnnotationAwareOrderComparator.sort(mappings);
  for (SimpleUrlHandlerMapping mapping : mappings) {
    for (String pattern : mapping.getHandlerMap().keySet()) {
      Object handler = mapping.getHandlerMap().get(pattern);
      if (handler instanceof ResourceHttpRequestHandler) {
        ResourceHttpRequestHandler resourceHandler = (ResourceHttpRequestHandler) handler;
        this.handlerMap.put(pattern, resourceHandler);
      }
    }
  }
  if (this.handlerMap.isEmpty()) {
    logger.trace("No resource handling mappings found");
  }
}

代码示例来源：origin: prestodb/presto

public void setLocalDefinitions(Map<Class<?>, Class<?>> sourceMixins) {
  if (sourceMixins == null || sourceMixins.isEmpty()) {
    _localMixIns = null;
  } else {
    Map<ClassKey,Class<?>> mixIns = new HashMap<ClassKey,Class<?>>(sourceMixins.size());
    for (Map.Entry<Class<?>,Class<?>> en : sourceMixins.entrySet()) {
      mixIns.put(new ClassKey(en.getKey()), en.getValue());
    }
    _localMixIns = mixIns;
  }
}

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

@Override
@Nullable
public Class<?> predictBeanType(Class<?> beanClass, String beanName) {
  if (this.proxyTypes.isEmpty()) {
    return null;
  }
  Object cacheKey = getCacheKey(beanClass, beanName);
  return this.proxyTypes.get(cacheKey);
}

代码示例来源：origin: jenkinsci/jenkins

private boolean hasMatchingEnvVars2(Map<String,String> modelEnvVar) throws WindowsOSProcessException {
    if(modelEnvVar.isEmpty())
      // sanity check so that we don't start rampage.
      return false;
    SortedMap<String,String> envs = getEnvironmentVariables2();
    for (Entry<String,String> e : modelEnvVar.entrySet()) {
      String v = envs.get(e.getKey());
      if(v==null || !v.equals(e.getValue()))
        return false;   // no match
    }
    return true;
  }
}

代码示例来源：origin: skylot/jadx

private Object attachAnnotation(Object obj, CodePosition pos) {
  if (annotations.isEmpty()) {
    annotations = new HashMap<>();
  }
  return annotations.put(pos, obj);
}

代码示例来源：origin: apache/hbase

private void mergeAssignmentMaps(Map<ServerName, List<RegionInfo>> assignmentMap,
  Map<ServerName, List<RegionInfo>> otherAssignments) {
 if (otherAssignments == null || otherAssignments.isEmpty()) {
  return;
 }
 for (Entry<ServerName, List<RegionInfo>> entry : otherAssignments.entrySet()) {
  ServerName sn = entry.getKey();
  List<RegionInfo> regionsList = entry.getValue();
  if (assignmentMap.get(sn) == null) {
   assignmentMap.put(sn, Lists.newArrayList(regionsList));
  } else {
   assignmentMap.get(sn).addAll(regionsList);
  }
 }
}

代码示例来源：origin: apache/geode

protected void initializeFieldAnalyzers(Map<String, Analyzer> fieldAnalyzers) {
 this.fieldAnalyzers = new HashMap<>();
 for (String field : fieldNames) {
  if (fieldAnalyzers != null && !fieldAnalyzers.isEmpty()) {
   this.fieldAnalyzers.put(field,
     fieldAnalyzers.get(field) == null ? StandardAnalyzer.class.getSimpleName()
       : fieldAnalyzers.get(field).getClass().getSimpleName());
  } else {
   this.fieldAnalyzers.put(field, StandardAnalyzer.class.getSimpleName());
  }
 }
}

代码示例来源：origin: Graylog2/graylog2-server

private Map<String, String> prefixElements(final String prefix, final Map<String, String> elements) {
    if (elements == null || elements.isEmpty()) {
      return Collections.emptyMap();
    }

    final Map<String, String> prefixedMap = new HashMap<>(elements.size());
    for (Map.Entry<String, String> entry : elements.entrySet()) {
      prefixedMap.put(prefix.trim() + "_" + entry.getKey(), entry.getValue());
    }

    return prefixedMap;
  }
}

代码示例来源：origin: eclipse-vertx/vert.x

public X509KeyManager getKeyMgr(String serverName) {
 X509KeyManager mgr = mgrMap.get(serverName);
 if (mgr == null && !wildcardMgrMap.isEmpty()) {
  int index = serverName.indexOf('.') + 1;
  if (index > 0) {
   String s = serverName.substring(index);
   mgr = wildcardMgrMap.get(s);
  }
 }
 return mgr;
}

代码示例来源：origin: bumptech/glide

@Override
public String toString() {
 StringBuilder sb =
   new StringBuilder()
     .append("SizeConfigStrategy{groupedMap=")
     .append(groupedMap)
     .append(", sortedSizes=(");
 for (Map.Entry<Bitmap.Config, NavigableMap<Integer, Integer>> entry : sortedSizes.entrySet()) {
  sb.append(entry.getKey()).append('[').append(entry.getValue()).append("], ");
 }
 if (!sortedSizes.isEmpty()) {
  sb.replace(sb.length() - 2, sb.length(), "");
 }
 return sb.append(")}").toString();
}

代码示例来源：origin: square/okhttp

/**
 * Attaches {@code tag} to the request using {@code type} as a key. Tags can be read from a
 * request using {@link Request#tag}. Use null to remove any existing tag assigned for {@code
 * type}.
 *
 * <p>Use this API to attach timing, debugging, or other application data to a request so that
 * you may read it in interceptors, event listeners, or callbacks.
 */
public <T> Builder tag(Class<? super T> type, @Nullable T tag) {
 if (type == null) throw new NullPointerException("type == null");
 if (tag == null) {
  tags.remove(type);
 } else {
  if (tags.isEmpty()) tags = new LinkedHashMap<>();
  tags.put(type, type.cast(tag));
 }
 return this;
}