Example usage for java.util HashMap computeIfAbsent

Introduction

In this page you can find the example usage for java.util HashMap computeIfAbsent.

Prototype

@Override
public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) 

Source Link

Document

This method will, on a best-effort basis, throw a ConcurrentModificationException if it is detected that the mapping function modifies this map during computation.

Usage

From source file:org.apache.lens.cube.parse.PruneCauses.java

private HashMap<CandidateTablePruneCause, List<T>> reverse() {
    HashMap<CandidateTablePruneCause, List<T>> result = new HashMap<CandidateTablePruneCause, List<T>>();
    for (T key : keySet()) {
        for (CandidateTablePruneCause value : get(key)) {
            result.computeIfAbsent(value, k -> new ArrayList<>()).add(key);
        }// w  ww.  ja  v  a 2s  .co  m
    }
    return result;
}

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From source file:org.hyperledger.fabric.sdk.SDKUtils.java

/**
 * Check that the proposals all have consistent read write sets
 *
 * @param proposalResponses/*from  www  .  ja v a  2  s  .  c  o  m*/
 * @param invalid           proposals that were found to be invalid.
 * @return A Collection of sets where each set has consistent proposals.
 * @throws InvalidArgumentException
 */

public static Collection<Set<ProposalResponse>> getProposalConsistencySets(
        Collection<ProposalResponse> proposalResponses, Set<ProposalResponse> invalid)
        throws InvalidArgumentException {

    if (proposalResponses == null) {
        throw new InvalidArgumentException("proposalResponses collection is null");
    }

    if (proposalResponses.isEmpty()) {
        throw new InvalidArgumentException("proposalResponses collection is empty");
    }

    if (null == invalid) {
        throw new InvalidArgumentException("invalid set is null.");
    }

    HashMap<ByteString, Set<ProposalResponse>> ret = new HashMap<>();

    for (ProposalResponse proposalResponse : proposalResponses) {

        if (proposalResponse.isInvalid()) {
            invalid.add(proposalResponse);
        } else {
            // payload bytes is what's being signed over so it must be consistent.
            final ByteString payloadBytes = proposalResponse.getPayloadBytes();

            if (payloadBytes == null) {
                throw new InvalidArgumentException(
                        format("proposalResponse.getPayloadBytes() was null from peer: %s.",
                                proposalResponse.getPeer()));
            } else if (payloadBytes.isEmpty()) {
                throw new InvalidArgumentException(
                        format("proposalResponse.getPayloadBytes() was empty from peer: %s.",
                                proposalResponse.getPeer()));
            }
            Set<ProposalResponse> set = ret.computeIfAbsent(payloadBytes, k -> new HashSet<>());
            set.add(proposalResponse);
        }
    }

    if (IS_DEBUG_LEVEL && ret.size() > 1) {

        StringBuilder sb = new StringBuilder(1000);

        int i = 0;
        String sep = "";

        for (Map.Entry<ByteString, Set<ProposalResponse>> entry : ret.entrySet()) {
            ByteString bytes = entry.getKey();
            Set<ProposalResponse> presp = entry.getValue();

            sb.append(sep).append("Consistency set: ").append(i++).append(" bytes size: ").append(bytes.size())
                    .append(" bytes: ").append(Utils.toHexString(bytes.toByteArray())).append(" [");

            String psep = "";

            for (ProposalResponse proposalResponse : presp) {
                sb.append(psep).append(proposalResponse.getPeer());
                psep = ", ";
            }
            sb.append("]");
            sep = ", ";
        }

        logger.debug(sb.toString());

    }

    return ret.values();

}

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