Example usage for java.util Collections emptySortedSet

Introduction

In this page you can find the example usage for java.util Collections emptySortedSet.

Prototype

@SuppressWarnings("unchecked")
public static <E> SortedSet<E> emptySortedSet() 

Source Link

Document

Returns an empty sorted set (immutable).

Usage

From source file:ddf.security.impl.SubjectIdentityImpl.java

private SortedSet<String> getSubjectAttribute(Subject subject) {
    Map<String, SortedSet<String>> attrs = SubjectUtils.getSubjectAttributes(subject);

    if (attrs.containsKey(identityAttribute)) {
        return attrs.get(identityAttribute);
    }//w  w  w. j  a v  a 2 s  .  c o  m

    return Collections.emptySortedSet();
}

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From source file:org.apache.hadoop.hbase.replication.ZKReplicationQueueStorage.java

@Override
public Pair<String, SortedSet<String>> claimQueue(ServerName sourceServerName, String queueId,
        ServerName destServerName) throws ReplicationException {
    LOG.info("Atomically moving {}/{}'s WALs to {}", sourceServerName, queueId, destServerName);
    try {// w ww  .j a v a  2s  . co  m
        ZKUtil.createWithParents(zookeeper, getRsNode(destServerName));
    } catch (KeeperException e) {
        throw new ReplicationException("Claim queue queueId=" + queueId + " from " + sourceServerName + " to "
                + destServerName + " failed when creating the node for " + destServerName, e);
    }
    String newQueueId = queueId + "-" + sourceServerName;
    try {
        String oldQueueNode = getQueueNode(sourceServerName, queueId);
        List<String> wals = ZKUtil.listChildrenNoWatch(zookeeper, oldQueueNode);
        if (CollectionUtils.isEmpty(wals)) {
            ZKUtil.deleteNodeFailSilent(zookeeper, oldQueueNode);
            LOG.info("Removed empty {}/{}", sourceServerName, queueId);
            return new Pair<>(newQueueId, Collections.emptySortedSet());
        }
        String newQueueNode = getQueueNode(destServerName, newQueueId);
        List<ZKUtilOp> listOfOps = new ArrayList<>();
        SortedSet<String> logQueue = new TreeSet<>();
        // create the new cluster znode
        listOfOps.add(ZKUtilOp.createAndFailSilent(newQueueNode, HConstants.EMPTY_BYTE_ARRAY));
        // get the offset of the logs and set it to new znodes
        for (String wal : wals) {
            String oldWalNode = getFileNode(oldQueueNode, wal);
            byte[] logOffset = ZKUtil.getData(this.zookeeper, oldWalNode);
            LOG.debug("Creating {} with data {}", wal, Bytes.toStringBinary(logOffset));
            String newWalNode = getFileNode(newQueueNode, wal);
            listOfOps.add(ZKUtilOp.createAndFailSilent(newWalNode, logOffset));
            listOfOps.add(ZKUtilOp.deleteNodeFailSilent(oldWalNode));
            logQueue.add(wal);
        }
        // add delete op for peer
        listOfOps.add(ZKUtilOp.deleteNodeFailSilent(oldQueueNode));

        LOG.trace("The multi list size is {}", listOfOps.size());
        ZKUtil.multiOrSequential(zookeeper, listOfOps, false);

        LOG.info("Atomically moved {}/{}'s WALs to {}", sourceServerName, queueId, destServerName);
        return new Pair<>(newQueueId, logQueue);
    } catch (NoNodeException | NodeExistsException | NotEmptyException | BadVersionException e) {
        // Multi call failed; it looks like some other regionserver took away the logs.
        // These exceptions mean that zk tells us the request can not be execute. So return an empty
        // queue to tell the upper layer that claim nothing. For other types of exception should be
        // thrown out to notify the upper layer.
        LOG.info("Claim queue queueId={} from {} to {} failed with {}, someone else took the log?", queueId,
                sourceServerName, destServerName, e.toString());
        return new Pair<>(newQueueId, Collections.emptySortedSet());
    } catch (KeeperException | InterruptedException e) {
        throw new ReplicationException("Claim queue queueId=" + queueId + " from " + sourceServerName + " to "
                + destServerName + " failed", e);
    }
}

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From source file:org.eclipse.sw360.licenseinfo.outputGenerators.OutputGenerator.java

/**
 * Helper function to sort a set by the given key extractor. Falls back to the
 * unsorted set if sorting the set would squash values.
 *
 * @param unsorted/*from w w  w . j  a v  a 2s. com*/
 *            set to be sorted
 * @param keyExtractor
 *            function to extract the key to use for sorting
 *
 * @return the sorted set
 */
private static <U, K extends Comparable<K>> SortedSet<U> sortSet(Set<U> unsorted, Function<U, K> keyExtractor) {
    if (unsorted == null || unsorted.isEmpty()) {
        return Collections.emptySortedSet();
    }
    SortedSet<U> sorted = new TreeSet<>(Comparator.comparing(keyExtractor));
    sorted.addAll(unsorted);
    if (sorted.size() != unsorted.size()) {
        // there were key collisions and some data was lost -> throw away the sorted set
        // and sort by U's natural order
        sorted = new TreeSet<>();
        sorted.addAll(unsorted);
    }
    return sorted;
}

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From source file:org.hippoecm.frontend.editor.workflow.model.ReferringDocumentsProvider.java

static SortedSet<Node> getReferrersSortedByName(Node handle, final boolean retrieveUnpublished,
        final int resultMaxCount) throws RepositoryException {
    if (handle.isNodeType(HippoNodeType.NT_DOCUMENT)) {
        handle = handle.getParent();//from www  .  jav a 2s.  c  o m
    }
    if (!handle.isNodeType(HippoNodeType.NT_HANDLE)) {
        return Collections.emptySortedSet();
    }

    final Map<String, Node> referrers = new HashMap<>();
    final String uuid = handle.getIdentifier();

    final String requiredAvailability;
    if (retrieveUnpublished) {
        requiredAvailability = "preview";
    } else {
        requiredAvailability = "live";
    }

    StringBuilder queryBuilder = new StringBuilder("//element(*,hippo:facetselect)[@hippo:docbase='")
            .append(uuid).append("']");
    addReferrers(handle, requiredAvailability, resultMaxCount, queryBuilder.toString(), referrers);

    queryBuilder = new StringBuilder("//element(*,hippo:mirror)[@hippo:docbase='").append(uuid).append("']");
    addReferrers(handle, requiredAvailability, resultMaxCount, queryBuilder.toString(), referrers);

    return getSortedReferrers(referrers.values());
}

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