Example usage for java.util Deque peek

List of usage examples for java.util Deque peek

Introduction

In this page you can find the example usage for java.util Deque peek.

Prototype

E peek();

Source Link

Document

Retrieves, but does not remove, the head of the queue represented by this deque (in other words, the first element of this deque), or returns null if this deque is empty.

Usage

From source file:com.reprezen.swaggerparser.test.BigParseTest.java

private Optional<? extends JsonOverlay<?>> getField(ObjectOverlay<?> modelObj, Deque<PathKey> path)
        throws IllegalArgumentException, IllegalAccessException {
    String key = "";
    boolean first = true;
    Optional<? extends JsonOverlay<?>> value = Optional.absent();
    if (path.peek() != null && path.peek().isIndex()) {
        // next path item is an index, so our only shot is to get a list overlay bound directly to this object's
        // json node
        value = modelObj.getFieldValue("");
        if (value.isPresent()
                && (value.get() instanceof ListOverlay || value.get() instanceof ValListOverlay)) {
            return value;
        }//  ww w. ja  v a  2 s  . c o  m
    }
    while (!value.isPresent()) {
        if (path.peek() == null || path.peek().isIndex()) {
            break;
        }
        String next = path.remove().getString();
        key = first ? next : key + ":" + next;
        value = modelObj.getFieldValue(key);
        first = false;
    }
    return value;
}

From source file:com.spotify.helios.agent.QueueingHistoryWriter.java

private TaskStatusEvent findEldestEvent() {
    // We don't lock anything because in the worst case, we just put things in out of order which
    // while not perfect, won't cause any actual harm.  Out of order meaning between jobids, not
    // within the same job id.  Whether this is the best strategy (as opposed to fullest deque)
    // is arguable.
    TaskStatusEvent current = null;//from  w w w. jav  a  2  s.  com
    for (Deque<TaskStatusEvent> queue : items.values()) {
        if (queue == null) {
            continue;
        }
        final TaskStatusEvent item = queue.peek();
        if (current == null || (item.getTimestamp() < current.getTimestamp())) {
            current = item;
        }
    }
    return current;
}

From source file:com.spotify.helios.agent.TaskHistoryWriter.java

private TaskStatusEvent findEldestEvent() {
    // We don't lock anything because in the worst case, we just put things in out of order which
    // while not perfect, won't cause any actual harm.  Out of order meaning between jobids, not
    // within the same job id.  Whether this is the best strategy (as opposed to fullest deque)
    // is arguable.
    TaskStatusEvent current = null;// w ww .j a v  a 2  s.co m
    for (final Deque<TaskStatusEvent> queue : items.values()) {
        if (queue == null) {
            continue;
        }
        final TaskStatusEvent item = queue.peek();
        if (current == null || (item.getTimestamp() < current.getTimestamp())) {
            current = item;
        }
    }
    return current;
}

From source file:com.spotify.helios.agent.QueueingHistoryWriter.java

private TaskStatusEvent getNext() {
    // Some explanation: We first find the eldest event from amongst the queues (ok, they're
    // deques, but we really use it as a put back queue), and only then to we try to get
    // a lock on the relevant queue from whence we got the event.  Assuming that all worked
    // *and* that the event we have wasn't rolled off due to max-size limitations, we then
    // pull the item off the queue and return it.  We're basically doing optimistic concurrency,
    // and skewing things so that adding to this should be cheap.

    while (true) {
        final TaskStatusEvent current = findEldestEvent();

        // Didn't find anything that needed processing?
        if (current == null) {
            return null;
        }// w  w w  . ja  va  2 s  . c  o  m

        final JobId id = current.getStatus().getJob().getId();
        final Deque<TaskStatusEvent> deque = items.get(id);
        if (deque == null) {
            // shouldn't happen because we should be the only one pulling items off, but....
            continue;
        }

        synchronized (deque) {
            if (!deque.peek().equals(current)) {
                // item got rolled off, try again
                continue;
            }

            // Pull it off the queue and be paranoid.
            final TaskStatusEvent newCurrent = deque.poll();
            count.decrementAndGet();
            checkState(current.equals(newCurrent), "current should equal newCurrent");
            // Safe because this is the *only* place we hold these two locks at the same time.
            synchronized (items) {
                // Extra paranoia: curDeque should always == deque
                final Deque<TaskStatusEvent> curDeque = items.get(id);
                if (curDeque != null && curDeque.isEmpty()) {
                    items.remove(id);
                }
            }
            return current;
        }
    }
}

From source file:de.escalon.hypermedia.spring.hydra.PagedResourcesSerializer.java

protected void serializeContext(Object bean, JsonGenerator jgen, SerializerProvider serializerProvider,
        Deque<LdContext> contextStack) throws IOException {
    // TODO: this code is duplicated from JacksonHydraSerializer, see there for considerations
    if (proxyUnwrapper != null) {
        bean = proxyUnwrapper.unwrapProxy(bean);
    }//from   w ww  .  j a  v  a  2s  .  com
    MixinSource mixinSource = new JacksonMixinSource(serializerProvider.getConfig());
    final Class<?> mixInClass = mixinSource.findMixInClassFor(bean.getClass());

    final LdContext parentContext = contextStack.peek();
    LdContext currentContext = new LdContext(parentContext,
            ldContextFactory.getVocab(mixinSource, bean, mixInClass),
            ldContextFactory.getTerms(mixinSource, bean, mixInClass));
    contextStack.push(currentContext);
    // check if we need to write a context for the current bean at all
    // If it is in the same vocab: no context
    // If the terms are already defined in the context: no context
    boolean mustWriteContext;
    if (parentContext == null || !parentContext.contains(currentContext)) {
        mustWriteContext = true;
    } else {
        mustWriteContext = false;
    }

    if (mustWriteContext) {
        // begin context
        // default context: schema.org vocab or vocab package annotation
        jgen.writeObjectFieldStart("@context");
        // do not repeat vocab if already defined in current context
        if (parentContext == null || parentContext.vocab == null
                || (currentContext.vocab != null && !currentContext.vocab.equals(parentContext.vocab))) {
            jgen.writeStringField(JsonLdKeywords.AT_VOCAB, currentContext.vocab);
        }

        for (Map.Entry<String, Object> termEntry : currentContext.terms.entrySet()) {
            if (termEntry.getValue() instanceof String) {
                jgen.writeStringField(termEntry.getKey(), termEntry.getValue().toString());
            } else {
                jgen.writeObjectField(termEntry.getKey(), termEntry.getValue());
            }
        }
        jgen.writeEndObject();
        // end context
    }
}

From source file:de.escalon.hypermedia.spring.de.escalon.hypermedia.spring.jackson.LinkListSerializer.java

@Override
public void serialize(List<Link> links, JsonGenerator jgen, SerializerProvider serializerProvider)
        throws IOException {

    try {//from  w w w  .ja va2  s  . c o m
        Collection<Link> simpleLinks = new ArrayList<Link>();
        Collection<Affordance> affordances = new ArrayList<Affordance>();
        Collection<Link> templatedLinks = new ArrayList<Link>();
        Collection<Affordance> templatedAffordances = new ArrayList<Affordance>();
        for (Link link : links) {
            if (link instanceof Affordance) {
                final Affordance affordance = (Affordance) link;
                final List<ActionDescriptor> actionDescriptors = affordance.getActionDescriptors();
                if (!actionDescriptors.isEmpty()) {
                    if (affordance.isTemplated()) {
                        templatedAffordances.add(affordance);
                    } else {
                        affordances.add(affordance);
                    }
                } else {
                    if (affordance.isTemplated()) {
                        templatedLinks.add(affordance);
                    } else {
                        simpleLinks.add(affordance);
                    }
                }
            } else if (link.isTemplated()) {
                templatedLinks.add(link);
            } else {
                simpleLinks.add(link);
            }
        }

        for (Affordance templatedAffordance : templatedAffordances) {
            jgen.writeObjectFieldStart(templatedAffordance.getRel());

            jgen.writeStringField("@type", "hydra:IriTemplate");
            jgen.writeStringField("hydra:template", templatedAffordance.getHref());
            final List<ActionDescriptor> actionDescriptors = templatedAffordance.getActionDescriptors();
            ActionDescriptor actionDescriptor = actionDescriptors.get(0);
            jgen.writeArrayFieldStart("hydra:mapping");
            writeHydraVariableMapping(jgen, actionDescriptor, actionDescriptor.getPathVariableNames());
            writeHydraVariableMapping(jgen, actionDescriptor, actionDescriptor.getRequestParamNames());
            jgen.writeEndArray();

            jgen.writeEndObject();
        }
        for (Link templatedLink : templatedLinks) {
            // we only have the template, no access to method params
            jgen.writeObjectFieldStart(templatedLink.getRel());

            jgen.writeStringField("@type", "hydra:IriTemplate");
            jgen.writeStringField("hydra:template", templatedLink.getHref());

            jgen.writeArrayFieldStart("hydra:mapping");
            writeHydraVariableMapping(jgen, null, templatedLink.getVariableNames());
            jgen.writeEndArray();

            jgen.writeEndObject();
        }

        Deque<String> vocabStack = (Deque<String>) serializerProvider
                .getAttribute(JacksonHydraSerializer.KEY_LD_CONTEXT);
        String currentVocab = vocabStack != null ? vocabStack.peek() : null;

        for (Affordance affordance : affordances) {
            final String rel = affordance.getRel();
            List<ActionDescriptor> actionDescriptors = affordance.getActionDescriptors();
            if (!actionDescriptors.isEmpty()) {
                if (!Link.REL_SELF.equals(rel)) {
                    jgen.writeObjectFieldStart(rel); // begin rel
                }
                jgen.writeStringField(JacksonHydraSerializer.AT_ID, affordance.getHref());
                jgen.writeArrayFieldStart("hydra:operation");
            }

            for (ActionDescriptor actionDescriptor : actionDescriptors) {
                jgen.writeStartObject(); // begin a hydra:Operation

                final String semanticActionType = actionDescriptor.getSemanticActionType();
                if (semanticActionType != null) {
                    jgen.writeStringField("@type", semanticActionType);
                }
                jgen.writeStringField("hydra:method", actionDescriptor.getHttpMethod().name());

                final ActionInputParameter requestBodyInputParameter = actionDescriptor.getRequestBody();
                if (requestBodyInputParameter != null) {

                    jgen.writeObjectFieldStart("hydra:expects"); // begin hydra:expects

                    final Class<?> clazz = requestBodyInputParameter.getNestedParameterType();
                    final Expose classExpose = clazz.getAnnotation(Expose.class);
                    final String typeName;
                    if (classExpose != null) {
                        typeName = classExpose.value();
                    } else {
                        typeName = requestBodyInputParameter.getNestedParameterType().getSimpleName();
                    }
                    jgen.writeStringField("@type", typeName);

                    jgen.writeArrayFieldStart("hydra:supportedProperty"); // begin hydra:supportedProperty
                    // TODO check need for actionDescriptor and requestBodyInputParameter here:
                    recurseSupportedProperties(jgen, currentVocab, clazz, actionDescriptor,
                            requestBodyInputParameter, requestBodyInputParameter.getCallValue());
                    jgen.writeEndArray(); // end hydra:supportedProperty

                    jgen.writeEndObject(); // end hydra:expects
                }

                jgen.writeEndObject(); // end hydra:Operation
            }

            if (!actionDescriptors.isEmpty()) {
                jgen.writeEndArray(); // end hydra:operation

                if (!Link.REL_SELF.equals(rel)) {
                    jgen.writeEndObject(); // end rel
                }
            }
        }

        for (Link simpleLink : simpleLinks) {
            final String rel = simpleLink.getRel();
            if (Link.REL_SELF.equals(rel)) {
                jgen.writeStringField("@id", simpleLink.getHref());
            } else {
                String linkAttributeName = IanaRels.isIanaRel(rel) ? IANA_REL_PREFIX + rel : rel;
                jgen.writeObjectFieldStart(linkAttributeName);
                jgen.writeStringField("@id", simpleLink.getHref());
                jgen.writeEndObject();
            }
        }
    } catch (IntrospectionException e) {
        throw new RuntimeException(e);
    }
}

From source file:com.streamsets.datacollector.definition.ConfigDefinitionExtractor.java

void resolveDependencies(String configPrefix, List<ConfigDefinition> defs, Object contextMsg) {
    Map<String, ConfigDefinition> definitionsMap = new HashMap<>();
    Map<String, Map<String, Set<Object>>> dependencyMap = new HashMap<>();
    Map<String, Boolean> isFullyProcessed = new HashMap<>();
    for (ConfigDefinition def : defs) {
        definitionsMap.put(def.getName(), def);
        dependencyMap.put(def.getName(), new HashMap<String, Set<Object>>());
        isFullyProcessed.put(def.getName(), false);
    }/*from   w  w w .  j  a  v a  2 s .c  o m*/

    cycles.clear();

    for (ConfigDefinition def : defs) {
        String dependsOnKey = def.getDependsOn();
        if (!StringUtils.isEmpty(dependsOnKey)) {
            verifyDependencyExists(definitionsMap, def, dependsOnKey, contextMsg);
            ConfigDefinition dependsOnDef = definitionsMap.get(dependsOnKey);
            // evaluate dependsOn triggers
            ConfigDef annotation = def.getConfigField().getAnnotation(ConfigDef.class);
            Set<Object> triggers = new HashSet<>();
            for (String trigger : annotation.triggeredByValue()) {
                triggers.add(ConfigValueExtractor.get().extract(dependsOnDef.getConfigField(),
                        dependsOnDef.getType(), trigger, contextMsg, true));
            }
            dependencyMap.get(def.getName()).put(dependsOnDef.getName(), triggers);
        }
        // Add direct dependencies to dependencyMap
        if (!def.getDependsOnMap().isEmpty()) {
            // Copy same as above.
            for (Map.Entry<String, List<Object>> dependsOn : def.getDependsOnMap().entrySet()) {
                dependsOnKey = dependsOn.getKey();
                if (!StringUtils.isEmpty(dependsOnKey)) {
                    verifyDependencyExists(definitionsMap, def, dependsOnKey, contextMsg);
                    Set<Object> triggers = new HashSet<>();
                    ConfigDefinition dependsOnDef = definitionsMap.get(dependsOnKey);
                    for (Object trigger : dependsOn.getValue()) {
                        triggers.add(ConfigValueExtractor.get().extract(dependsOnDef.getConfigField(),
                                dependsOnDef.getType(), (String) trigger, contextMsg, true));
                    }
                    Map<String, Set<Object>> dependencies = dependencyMap.get(def.getName());
                    if (dependencies.containsKey(dependsOnKey)) {
                        dependencies.get(dependsOnKey).addAll(triggers);
                    } else {
                        dependencies.put(dependsOnKey, triggers);
                    }
                }
            }
        }
    }

    for (ConfigDefinition def : defs) {

        if (isFullyProcessed.get(def.getName())) {
            continue;
        }
        // Now find all indirect dependencies
        Deque<StackNode> stack = new ArrayDeque<>();
        stack.push(new StackNode(def, new LinkedHashSet<String>()));
        while (!stack.isEmpty()) {
            StackNode current = stack.peek();
            // We processed this one's dependencies before, don't bother adding its children
            // The dependencies of this one have all been processed
            if (current.childrenAddedToStack) {
                stack.pop();
                Map<String, Set<Object>> currentDependencies = dependencyMap.get(current.def.getName());
                Set<String> children = new HashSet<>(current.def.getDependsOnMap().keySet());
                for (String child : children) {
                    if (StringUtils.isEmpty(child)) {
                        continue;
                    }
                    Map<String, Set<Object>> depsOfChild = dependencyMap.get(child);
                    for (Map.Entry<String, Set<Object>> depOfChild : depsOfChild.entrySet()) {
                        if (currentDependencies.containsKey(depOfChild.getKey())) {
                            // Add only the common trigger values,
                            // since it has to be one of those for both these to be triggered.
                            Set<Object> currentTriggers = currentDependencies.get(depOfChild.getKey());
                            Set<Object> childTriggers = depOfChild.getValue();
                            currentDependencies.put(depOfChild.getKey(),
                                    Sets.intersection(currentTriggers, childTriggers));
                        } else {
                            currentDependencies.put(depOfChild.getKey(), new HashSet<>(depOfChild.getValue()));
                        }
                    }
                }
                isFullyProcessed.put(current.def.getName(), true);
            } else {
                Set<String> children = current.def.getDependsOnMap().keySet();
                String dependsOn = current.def.getDependsOn();
                LinkedHashSet<String> dependencyAncestors = new LinkedHashSet<>(current.ancestors);
                dependencyAncestors.add(current.def.getName());
                if (!StringUtils.isEmpty(dependsOn) && !isFullyProcessed.get(current.def.getDependsOn())
                        && !detectCycle(dependencyAncestors, cycles, dependsOn)) {
                    stack.push(
                            new StackNode(definitionsMap.get(current.def.getDependsOn()), dependencyAncestors));
                }
                for (String child : children) {
                    if (!StringUtils.isEmpty(child) && !isFullyProcessed.get(child)
                            && !detectCycle(dependencyAncestors, cycles, child)) {
                        stack.push(new StackNode(definitionsMap.get(child), dependencyAncestors));
                    }
                }
                current.childrenAddedToStack = true;
            }
        }
    }
    Preconditions.checkState(cycles.isEmpty(),
            "The following cycles were detected in the configuration dependencies:\n"
                    + Joiner.on("\n").join(cycles));
    for (Map.Entry<String, Map<String, Set<Object>>> entry : dependencyMap.entrySet()) {
        Map<String, List<Object>> dependencies = new HashMap<>();
        definitionsMap.get(entry.getKey()).setDependsOnMap(dependencies);
        for (Map.Entry<String, Set<Object>> trigger : entry.getValue().entrySet()) {
            List<Object> triggerValues = new ArrayList<>();
            triggerValues.addAll(trigger.getValue());
            dependencies.put(trigger.getKey(), triggerValues);
        }
        definitionsMap.get(entry.getKey()).setDependsOn("");
    }
}

From source file:RandomChooser.java

private RandomChooser(List<Double> weights, List<T> events, Random random) {
    double sum = 0.0;
    for (double prob : weights)
        sum += prob;/*from w  w w. j  av a 2s . co  m*/

    this.probs = new double[weights.size()];
    for (int i = 0; i < weights.size(); i++) {
        probs[i] = weights.get(i) * weights.size() / sum; //average = 1.0
    }

    Deque<Integer> smaller = new ArrayDeque<Integer>(weights.size() / 2 + 2);
    Deque<Integer> greater = new ArrayDeque<Integer>(weights.size() / 2 + 2);
    for (int i = 0; i < probs.length; i++) {
        if (probs[i] < 1.0) {
            smaller.push(i);
        } else {
            greater.push(i);
        }
    }
    indexes = new int[weights.size()];
    while (!smaller.isEmpty()) {
        Integer i = smaller.pop();
        Integer k = greater.peek();
        indexes[i] = k;
        probs[k] -= (1 - probs[i]);
        if (probs[k] < 1.0) {
            greater.pop();
            if (greater.isEmpty())
                break;
            smaller.push(k);
        }
    }
    this.events = events;
    this.random = random;
}

From source file:net.dv8tion.jda.core.entities.impl.ReceivedMessage.java

@Override
public String getContentStripped() {
    if (strippedContent != null)
        return strippedContent;
    synchronized (mutex) {
        if (strippedContent != null)
            return strippedContent;
        String tmp = getContentDisplay();
        //all the formatting keys to keep track of
        String[] keys = new String[] { "*", "_", "`", "~~" };

        //find all tokens (formatting strings described above)
        TreeSet<FormatToken> tokens = new TreeSet<>(Comparator.comparingInt(t -> t.start));
        for (String key : keys) {
            Matcher matcher = Pattern.compile(Pattern.quote(key)).matcher(tmp);
            while (matcher.find())
                tokens.add(new FormatToken(key, matcher.start()));
        }/*from  w  w w .  java  2  s  .co  m*/

        //iterate over all tokens, find all matching pairs, and add them to the list toRemove
        Deque<FormatToken> stack = new ArrayDeque<>();
        List<FormatToken> toRemove = new ArrayList<>();
        boolean inBlock = false;
        for (FormatToken token : tokens) {
            if (stack.isEmpty() || !stack.peek().format.equals(token.format)
                    || stack.peek().start + token.format.length() == token.start)

            {
                //we are at opening tag
                if (!inBlock) {
                    //we are outside of block -> handle normally
                    if (token.format.equals("`")) {
                        //block start... invalidate all previous tags
                        stack.clear();
                        inBlock = true;
                    }
                    stack.push(token);
                } else if (token.format.equals("`")) {
                    //we are inside of a block -> handle only block tag
                    stack.push(token);
                }
            } else if (!stack.isEmpty()) {
                //we found a matching close-tag
                toRemove.add(stack.pop());
                toRemove.add(token);
                if (token.format.equals("`") && stack.isEmpty())
                    //close tag closed the block
                    inBlock = false;
            }
        }

        //sort tags to remove by their start-index and iteratively build the remaining string
        toRemove.sort(Comparator.comparingInt(t -> t.start));
        StringBuilder out = new StringBuilder();
        int currIndex = 0;
        for (FormatToken formatToken : toRemove) {
            if (currIndex < formatToken.start)
                out.append(tmp.substring(currIndex, formatToken.start));
            currIndex = formatToken.start + formatToken.format.length();
        }
        if (currIndex < tmp.length())
            out.append(tmp.substring(currIndex));
        //return the stripped text, escape all remaining formatting characters (did not have matching
        // open/close before or were left/right of block
        return strippedContent = out.toString().replace("*", "\\*").replace("_", "\\_").replace("~", "\\~");
    }
}