java.util.LinkedList#isEmpty ( )源码实例Demo

static private void setup_extension(DataDstOneofDescriptor child_field, Descriptors.Descriptor container,
        Descriptors.OneofDescriptor fd) {
    LinkedList<DataVerifyImpl> gen = setup_verifier(container, fd);
    if (gen != null && !gen.isEmpty()) {
        for (DataVerifyImpl vfy : gen) {
            child_field.addVerifier(vfy);
        }
    } else {
        child_field.resetVerifier();
    }

    if (fd.getOptions().hasExtension(Xresloader.oneofDescription)) {
        child_field.mutableExtension().description = fd.getOptions().getExtension(Xresloader.oneofDescription);
    }

    if (fd.getOptions().hasExtension(Xresloader.oneofSeparator)) {
        child_field.mutableExtension().plainSeparator = fd.getOptions().getExtension(Xresloader.oneofSeparator);
    }
}
 

/**
 * Searches (by breadth-first search) the node in this model whose user object is equal to the given object.
 * 
 * @param object
 * @return The node whose user object is equal to the given object or null
 */
public TreeNode findNodeByUserObject(Object object) {
    LinkedList<TreeNode> queue = new LinkedList<TreeNode>();
    // initialize the queue by the root node
    queue.add(getRootNode());
    do {
        // dequeue and examine
        TreeNode node = queue.poll();
        Object currentNodesObject = node.getUserObject();
        if (object.equals(currentNodesObject)) {
            return node;
        } else {
            // enqueue successors
            for (int i = 0; i < node.getChildCount(); i++) {
                queue.add((TreeNode) node.getChildAt(i));
            }
        }
    } while (!queue.isEmpty());
    // the node couldn't be found
    return null;
}
 

/**
   * @param root
   * @return returns a list of all files (including those in sub-directories)
   */
  public static List<File> listAllFiles(File root) {
LinkedList<File> files = new LinkedList<>();

if(root.isDirectory()) {
	LinkedList<File> toList = new LinkedList<>(Arrays.asList(root.listFiles()));
	
	while(!toList.isEmpty()) {
		File f = toList.poll();
		
		if(f.isDirectory()) {
			toList.addAll(Arrays.asList(f.listFiles()));
		} else {
			files.add(f);
		}
	}
} else {
	files.add(root);
}

return files;
  }
 

private static StatsSnapshot computeStatsData(final LinkedList<CallSnapshot> csList) {
    StatsSnapshot statsSnapshot = new StatsSnapshot();
    synchronized (csList) {
        double tps = 0;
        double avgpt = 0;
        long sum = 0;
        if (!csList.isEmpty()) {
            CallSnapshot first = csList.getFirst();
            CallSnapshot last = csList.getLast();
            sum = last.getValue() - first.getValue();
            tps = (sum * 1000.0d) / (last.getTimestamp() - first.getTimestamp());

            long timesDiff = last.getTimes() - first.getTimes();
            if (timesDiff > 0) {
                avgpt = (sum * 1.0d) / timesDiff;
            }
        }

        statsSnapshot.setSum(sum);
        statsSnapshot.setTps(tps);
        statsSnapshot.setAvgpt(avgpt);
    }

    return statsSnapshot;
}
 

private void dfsReachRel(int stateFrom, Map<Integer, Integer> stateToId, boolean[][] reachRel,
		Map<Integer, Collection<Integer>> wmRelList) {

	HashSet<Integer> reached = new HashSet<>();
	LinkedList<Integer> toVisit = new LinkedList<>();
	toVisit.add(stateFrom);

	int id = stateToId.get(stateFrom);

	while (!toVisit.isEmpty()) {
		int state = toVisit.removeFirst();

		// Epsilon Transition
		for (Integer to : wmRelList.get(state)) {
			if (!reached.contains(to)) {
				reachRel[id][stateToId.get(to)] = true;
				wmRelList.get(stateFrom).add(to);
				toVisit.add(to);
				reached.add(to);
			}
		}
	}
}
 

public TreeNode findKthNode(TreeNode pRoot, int k) {
    if (pRoot == null || k <= 0) return null;
    LinkedList<TreeNode> stack = new LinkedList<>();
    int count = 0;
    while (pRoot != null || !stack.isEmpty()) {
        while (pRoot != null) {
            stack.push(pRoot);
            pRoot = pRoot.left;
        }
        if (!stack.isEmpty()) {
            pRoot = stack.pop();
            if (++count == k) return pRoot;
            pRoot = pRoot.right;
        }
    }
    return null;
}
 

public void addChild ( final LinkedList<String> path, final ZipEntry zipEntry )
{
    final String seg = path.pop ();

    Entry child = this.children.get ( seg );
    if ( child == null )
    {
        final List<String> ids = new ArrayList<> ( this.ids );
        ids.add ( seg );
        child = new Entry ( ids );
        this.children.put ( seg, child );
    }

    if ( path.isEmpty () )
    {
        child.zipEntry = zipEntry;
    }
    else
    {
        child.addChild ( path, zipEntry );
    }
}
 

/**
 * protected method to assist in building "pullbackpath" strings for the
 * pullback constraint annotations
 *
 * @param inEdges     List of sketchedges
 * @param includeLast Include the last or not
 * @return path like string
 */
protected String xmlPBJoinPath(final List<SketchEdge> inEdges, final boolean includeLast) {
	final LinkedList<SketchEdge> edges = new LinkedList<>(inEdges);
	final StringBuilder joinClause = new StringBuilder(quoteId(edges.get(0).getSourceEntity().getName()));

	if (!includeLast && !edges.isEmpty()) {
		edges.removeLast();
	}

	for (final SketchEdge e : edges) {
		final EntityNode target = e.getTargetEntity();

		joinClause.append('(').append(e.getName()).append(")->").append(target.getName());
	}

	return joinClause.toString();
}
 

/** Can copy a Treeline to an AreaTree and viceversa.
 *  Copies the transform, the nodes (with tags and confidence), and the color. The transparency, locked stated and links are not copied. */
static public<A extends Tree<?>, B extends Node<?>> A copyAs(final Tree<?> src, final Class<A> tree_class, final Class<B> node_class) throws Exception {
	final String title = "copy of " + src.title + " #" + src.id;
	final A t = tree_class.getConstructor(Project.class, String.class).newInstance(src.project, title);
	t.at.setTransform(src.at);
	t.color = src.color;
	t.width = src.width;
	t.height = src.height;

	final Map<Node<?>,B> rel = new HashMap<Node<?>,B>();
	final LinkedList<Node<?>> todo = new LinkedList<Node<?>>();
	//t.root = new Treeline.RadiusNode(src.root.x, src.root.y, src.root.la);
	todo.add(src.root);
	while (!todo.isEmpty()) {
		final Node<?> a = todo.removeLast();
		// Put all children nodes to the end of the todo list
		if (null != a.children)
			for (final Node<?> child : a.children)
				todo.add(child);
		// Copy the content of the 'a' node
		final B copy = node_class.getConstructor(Float.TYPE, Float.TYPE, Layer.class).newInstance(a.x, a.y, a.la);
		copy.copyProperties(a);
		// Store relationship between original and copy
		rel.put(a, copy);
		// Find parent if any
		if (null == a.parent) {
			// Set the copy as the root
			t.root = (Node)copy; // need to cast
			continue;
		}
		// .. and if found, add the copy to the copied parent:
		rel.get(a.parent).add((Node)copy, copy.confidence); // TODO no other way than to cast?
	}
	// create internals
	t.cacheSubtree((Collection)t.root.getSubtreeNodes());
	return t;
}
 

public synchronized V get(C category) {
    LinkedList<V> cat = storage.get(category);
    if (cat == null || cat.isEmpty())
        return constructor == null ? null : constructor.invoke(category);
    V found = cat.removeLast();
    if (found != null)
        resurrect.invoke(found);
    return found;
}
 

public void registerComponent ( final LinkedList<String> prefix, final ComponentFolder componentFolder, final Component component )
{
    logger.debug ( "Register - prefix: {}, componentFolder: {}, component: {}", prefix, componentFolder, component );

    // first get the name
    final String next = prefix.pop ();

    if ( prefix.isEmpty () )
    {
        add ( next, componentFolder, component );
    }
    else
    {
        // add another sub level
        ComponentNode node = this.nodes.get ( next );
        if ( node == null )
        {
            if ( this.components.containsKey ( next ) )
            {
                // blocked by component

                // remove all folders we might have created
                checkRemove ();
                // throw exception
                throw new IllegalStateException ( "Namespace blocked by other component" );
            }

            final FolderCommon folder = new FolderCommon ();
            this.folder.add ( next, folder, null );

            node = new ComponentNode ( this, folder );
            this.nodes.put ( next, node );
        }
        node.registerComponent ( prefix, componentFolder, component );
    }
}
 

@Override
public Subject getRunAsSubject(final BeanContext callingBeanContext) {
    final Subject runAsSubject = super.getRunAsSubject(callingBeanContext);
    if (runAsSubject != null) {
        return runAsSubject;
    }

    final LinkedList<Subject> stack = RUN_AS_STACK.get();
    if (stack.isEmpty()) {
        return null;
    }
    return stack.getFirst();
}
 

/**
 * 计算数据
 * @param csList csList
 * @return ;
 */
private static StatsSnapshot computeStatsData(final LinkedList<CallSnapshot> csList) {
    StatsSnapshot statsSnapshot = new StatsSnapshot();
    synchronized (csList) {
        double tps = 0;
        double avgpt = 0;
        long sum = 0;
        if (!csList.isEmpty()) {
            CallSnapshot first = csList.getFirst();
            CallSnapshot last = csList.getLast();
            //sum=last-first
            sum = last.getValue() - first.getValue();
            //tps
            tps = (sum * 1000.0d) / (last.getTimestamp() - first.getTimestamp());

            long timesDiff = last.getTimes() - first.getTimes();
            if (timesDiff > 0) {
                //平均rt
                avgpt = (sum * 1.0d) / timesDiff;
            }
        }

        statsSnapshot.setSum(sum);
        statsSnapshot.setTps(tps);
        statsSnapshot.setAvgpt(avgpt);
    }

    return statsSnapshot;
}
 

/**
 * Takes one selector from end of LRU list of free selectors.
 * If there are no selectors awailable, it creates a new selector.
 * Also invokes trimIdleSelectors(). 
 * 
 * @param channel
 * @return 
 * @throws IOException
 */
private synchronized SelectorInfo get(SelectableChannel channel) 
                                                     throws IOException {
  SelectorInfo selInfo = null;
  
  SelectorProvider provider = channel.provider();
  
  // pick the list : rarely there is more than one provider in use.
  ProviderInfo pList = providerList;
  while (pList != null && pList.provider != provider) {
    pList = pList.next;
  }      
  if (pList == null) {
    //LOG.info("Creating new ProviderInfo : " + provider.toString());
    pList = new ProviderInfo();
    pList.provider = provider;
    pList.queue = new LinkedList<SelectorInfo>();
    pList.next = providerList;
    providerList = pList;
  }
  
  LinkedList<SelectorInfo> queue = pList.queue;
  
  if (queue.isEmpty()) {
    Selector selector = provider.openSelector();
    selInfo = new SelectorInfo();
    selInfo.selector = selector;
    selInfo.queue = queue;
  } else {
    selInfo = queue.removeLast();
  }
  
  trimIdleSelectors(System.currentTimeMillis());
  return selInfo;
}
 

/**
 * 题目：滑动窗口的最大值 思路：滑动窗口应当是队列，但为了得到滑动窗口的最大值，队列序可以从两端删除元素，因此使用双端队列。 原则： 对新来的元素k，将其与双端队列中的元素相比较
 * 1）前面比k小的，直接移出队列（因为不再可能成为后面滑动窗口的最大值了!）,
 * 2）前面比k大的X，比较两者下标，判断X是否已不在窗口之内，不在了，直接移出队列，队列的第一个元素是滑动窗口中的最大值
 */
public ArrayList<Integer> maxInWindows(int[] num, int size) {
    ArrayList<Integer> ret = new ArrayList<>();
    if (num == null) {
        return ret;
    }
    if (num.length < size || size < 1) {
        return ret;
    }
    // 双端队列，用来记录每个窗口的最大值下标
    LinkedList<Integer> indexDeque = new LinkedList<>();
    for (int i = 0; i < size - 1; i++) {
        while (!indexDeque.isEmpty() && num[i] > num[indexDeque.getLast()]) {
            indexDeque.removeLast();
        }
        indexDeque.addLast(i);
    }
    for (int i = size - 1; i < num.length; i++) {
        while (!indexDeque.isEmpty() && num[i] > num[indexDeque.getLast()]) {
            indexDeque.removeLast();
        }
        indexDeque.addLast(i);
        if (i - indexDeque.getFirst() + 1 > size) {
            indexDeque.removeFirst();
        }
        ret.add(num[indexDeque.getFirst()]);
    }
    return ret;
}
 

@SuppressWarnings({"rawtypes", "unchecked"})
private void scanMethods(LinkedList<MethodInvoker> methods, Map<String, MethodInvoker> toKeyMappers,
                         Map<String, MethodInvoker> toStringMappers, Set<String> knownProperties)
{
    int sizeBefore = methods.size();
    for (Iterator<MethodInvoker> iterator = methods.iterator(); iterator.hasNext(); )
    {
        MethodInvoker methodInvoker = iterator.next();
        ConfigPropertyTemplateImpl template;
        Class<?> returnType = methodInvoker.getReturnType();
        Type genericReturnType = methodInvoker.getGenericReturnType();
        String name;
        Method method = methodInvoker.getMethod();
        if (methodInvoker.isPrivate())
        {
            if (methodInvoker.isAnnotationPresent(ToKeyMapperFunction.class))
            {
                this.scanKeyMapper(methodInvoker, toKeyMappers);
                iterator.remove();
                continue;
            }
            if (methodInvoker.isAnnotationPresent(ToStringMapperFunction.class))
            {
                this.scanStringMapper(methodInvoker, toStringMappers);
                iterator.remove();
                continue;
            }
            name = this.extractName(methodInvoker);

            methodInvoker.ensureAccessible();
            if (! knownProperties.add(name))
            {
                throw new IllegalStateException("Duplicated property: " + name);
            }
            template = new ConfigPropertyTemplateImpl(this, returnType, genericReturnType, name, cfg -> methodInvoker.invoke(cfg), method);
        }
        else
        {
            Pair<ConfigPropertyAction, ActionMatcherResult> resultPair = ActionsRegistry.findMethod(method, knownProperties::contains);
            if (resultPair == null)
            {
                iterator.remove();
                continue;
            }
            ConfigPropertyAction propertyAction = resultPair.getLeft();
            if (! propertyAction.getActionName().equals("get") && methodInvoker.isDefault())
            {
                throw new RuntimeException("Unexpected default implementation of: " + method);
            }
            ActionMatcherResult matcherResult = resultPair.getRight();
            if (! matcherResult.isValidatedName())
            {
                continue; // wait for validation.
            }
            name = matcherResult.getPropertyName();

            ConfigPropertyTemplateImpl<?> oldTemplate = this.mutableProperties.get(name);
            if (oldTemplate != null)
            {
                template = oldTemplate;
            }
            else
            {
                if (! propertyAction.declaresProperty())
                {
                    continue;
                }
                if (! knownProperties.add(name))
                {
                    throw new IllegalStateException("Duplicated property: " + name);
                }
                template = new ConfigPropertyTemplateImpl(this, returnType, genericReturnType, name, cfg -> null, method);
            }

            if (propertyAction.getActionName().equals("get") && methodInvoker.isDefault())
            {
                this.defaultValueFromDefaultMethod(methodInvoker, template);
            }

            MethodSignature methodSignature = new MethodSignature(method);
            PropertyActionKey propertyActionKey = new PropertyActionKey(propertyAction, methodSignature);
            this.mutableActions.put(propertyActionKey, template);
            this.actionsDispatcher.put(methodSignature, propertyActionKey);
        }
        this.order.add(name);
        this.mutableProperties.put(name, template);
        iterator.remove();
    }
    if (methods.isEmpty())
    {
        return;
    }
    if (sizeBefore == methods.size())
    {
        throw new IllegalStateException("Can't create config template, can't find how to implement: " + methods);
    }
    this.scanMethods(methods, toKeyMappers, toStringMappers, knownProperties);
}
 

private static Set<URL> findReverseSourceRoots(final URL thisSourceRoot, Map<URL, List<URL>> sourceDeps, Map<URL, List<URL>> rootPeers, final FileObject thisFile) {
    long startTime = System.currentTimeMillis();

    try {
        //TODO: from SourceUtils (which filters out source roots that do not belong to open projects):
        //Create inverse dependencies
        final Map<URL, List<URL>> inverseDeps = new HashMap<URL, List<URL>> ();
        for (Map.Entry<URL,List<URL>> entry : sourceDeps.entrySet()) {
            final URL u1 = entry.getKey();
            final List<URL> l1 = entry.getValue();
            for (URL u2 : l1) {
                List<URL> l2 = inverseDeps.get(u2);
                if (l2 == null) {
                    l2 = new ArrayList<URL>();
                    inverseDeps.put (u2,l2);
                }
                l2.add (u1);
            }
        }
        //Collect dependencies
        final Set<URL> result = new HashSet<URL>();
        final LinkedList<URL> todo = new LinkedList<URL> ();
        todo.add (thisSourceRoot);
        List<URL> peers = rootPeers != null ? rootPeers.get(thisSourceRoot) : null;
        if (peers != null)
            todo.addAll(peers);
        while (!todo.isEmpty()) {
            final URL u = todo.removeFirst();
            if (!result.contains(u)) {
                result.add (u);
                final List<URL> ideps = inverseDeps.get(u);
                if (ideps != null) {
                    todo.addAll (ideps);
                }
            }
        }
        return result;
    } finally {
        long endTime = System.currentTimeMillis();

        Logger.getLogger("TIMER").log(Level.FINE, "Find Reverse Source Roots", //NOI18N
                new Object[]{thisFile, endTime - startTime});
    }
}
 

/**
 * Returns all the 'configured' network interfaces
 * 
 * @return list of network interfaces / NULL (in case of error)
 */
private static List<Interface> readInterfaces(){
	try{
		List<Interface> interfacesResult = new ArrayList<Interface>();
		
		Enumeration<NetworkInterface> networkInterfaces = NetworkInterface.getNetworkInterfaces();
		LinkedList<NetworkInterface> networkInterfacesList = new LinkedList<NetworkInterface>();
		while(networkInterfaces.hasMoreElements()){
			networkInterfacesList.addLast(networkInterfaces.nextElement());
		}
		
		while(!networkInterfacesList.isEmpty()){
			NetworkInterface networkInterface = networkInterfacesList.removeFirst();
			// Since there can be subinterfaces, adding all to the networkInterfaces list and processing them. 
			// Breadth first traversal.
			Enumeration<NetworkInterface> networkSubInterfaces = networkInterface.getSubInterfaces();
			while(networkSubInterfaces.hasMoreElements()){
				networkInterfacesList.addLast(networkSubInterfaces.nextElement());
			}
			
			Interface interfaceResult = new Interface();
			interfaceResult.name = unNullify(networkInterface.getName());
			interfaceResult.macAddress = parseBytesToMacAddress(networkInterface.getHardwareAddress());
			
			List<String> ips = new ArrayList<String>();
			Enumeration<InetAddress> inetAddresses = networkInterface.getInetAddresses();
			while(inetAddresses.hasMoreElements()){
				InetAddress inetAddress = inetAddresses.nextElement();
				byte[] ipBytes = inetAddress.getAddress();
				if(inetAddress instanceof Inet4Address){
					ips.add(parseBytesToIpv4(ipBytes));
				}else if(inetAddress instanceof Inet6Address){
					ips.add(parseBytesToIpv6(ipBytes));
				}else{
					logger.log(Level.WARNING, "Unknown address type: " + inetAddress);
				}
			}
			
			interfaceResult.ips = ips;
			
			interfacesResult.add(interfaceResult);
		}
		
		return interfacesResult;
	}catch(Exception e){
		logger.log(Level.SEVERE, "Failed to poll network interfaces", e);
	}
	return null;
}
 

@Override
public void heartbeatCheck(long timeout) {
	// 心跳
	for (PhysicalNode physicalNode : physicalNodes.values()) {
		// 心跳检测, 超时抛弃
		// --------------------------------------------------------------------------
		long heartbeatTime = TimeUtil.currentTimeMillis() - timeout;
		long closeTime = TimeUtil.currentTimeMillis() - (timeout * 2);

		LinkedList<BackendConnection> heartBeatCons = getNeedHeartbeatCons(physicalNode.conQueue.getCons(),
				heartbeatTime, closeTime);
		if (!heartBeatCons.isEmpty()) {
			for (BackendConnection conn : heartBeatCons) {
				
				// apiKeyId、 version、 clientId、correlation
				int correlationId = Utils.getCorrelationId();
				RequestHeader requestHeader = new RequestHeader(ApiKeys.API_VERSIONS.id, (short)1, CLIENT_ID, correlationId);
				Struct struct = requestHeader.toStruct();
				int size = struct.sizeOf() + 4;
				//
				ByteBuffer buffer = NetSystem.getInstance().getBufferPool().allocate( size );
				buffer.putInt(struct.sizeOf());
				struct.writeTo(buffer);
				
				conHeartBeatHanler.doHeartBeat(conn, buffer);
			}
		}
		heartBeatCons.clear();
		conHeartBeatHanler.abandTimeoutConns();

		// 连接池 动态调整逻辑
		// -------------------------------------------------------------------------------
		int idleCons = physicalNode.getIdleCount();
		int activeCons = physicalNode.getActiveCount();
		int minCons = poolCfg.getMinCon();
		int maxCons = poolCfg.getMaxCon();

		if (LOGGER.isDebugEnabled())
			LOGGER.debug("ClusterHeartbeat: host={}, idle={}, active={}, min={}, max={}, lasttime={}",
					new Object[] { physicalNode.getHost() + ":" + physicalNode.getPort(), idleCons, activeCons,
							minCons, maxCons, System.currentTimeMillis() });

		if (idleCons > minCons) {

			if (idleCons < activeCons) {
				return;
			}

			// 闲置太多
			closeByIdleMany(physicalNode, idleCons - minCons);

		} else if (idleCons < minCons) {

			if (idleCons > (minCons * 0.5)) {
				return;
			}

			// 闲置太少
			if ((idleCons + activeCons) < maxCons) {
				int createCount = (int) Math.ceil((minCons - idleCons) / 3F);
				createByIdleLitte(physicalNode, idleCons, createCount);
			}
		}
	}

}
 

private void filterOnDominance(DominatorTreeExceptionFilter filter) {

    DominatorEngine engine = filter.getDomEngine();

    for (Integer head : new HashSet<>(mapExtPostdominators.keySet())) {

      FastFixedSet<Integer> setPostdoms = mapExtPostdominators.get(head);

      LinkedList<Statement> stack = new LinkedList<>();
      LinkedList<FastFixedSet<Integer>> stackPath = new LinkedList<>();

      stack.add(statement.getStats().getWithKey(head));
      stackPath.add(factory.spawnEmptySet());

      Set<Statement> setVisited = new HashSet<>();

      setVisited.add(stack.getFirst());

      while (!stack.isEmpty()) {

        Statement stat = stack.removeFirst();
        FastFixedSet<Integer> path = stackPath.removeFirst();

        if (setPostdoms.contains(stat.id)) {
          path.add(stat.id);
        }

        if (path.contains(setPostdoms)) {
          continue;
        }

        if (!engine.isDominator(stat.id, head)) {
          setPostdoms.complement(path);
          continue;
        }

        for (StatEdge edge : stat.getSuccessorEdges(StatEdge.TYPE_REGULAR)) {

          Statement edge_destination = edge.getDestination();

          if (!setVisited.contains(edge_destination)) {

            stack.add(edge_destination);
            stackPath.add(path.getCopy());

            setVisited.add(edge_destination);
          }
        }
      }

      if (setPostdoms.isEmpty()) {
        mapExtPostdominators.remove(head);
      }
    }
  }