info.gehrels.voting.singleTransferableVote.CandidateStates.java Source code

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Here is the source code for info.gehrels.voting.singleTransferableVote.CandidateStates.java

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/*
 * Copyright  2014 Benjamin Gehrels
 *
 * This file is part of The Single Transferable Vote Elections Library.
 *
 * The Single Transferable Vote Elections Web Interface is free software: you can redistribute it and/or modify it under
 * the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * The Single Transferable Vote Elections Web Interface is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License along with The Single Transferable Vote
 * Elections Web Interface. If not, see <http://www.gnu.org/licenses/>.
 */
package info.gehrels.voting.singleTransferableVote;

import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableMap.Builder;
import com.google.common.collect.ImmutableSet;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;

final class CandidateStates<CANDIDATE_TYPE> implements Iterable<CandidateState<CANDIDATE_TYPE>> {
    private final ImmutableMap<CANDIDATE_TYPE, CandidateState<CANDIDATE_TYPE>> candidateStates;

    CandidateStates(ImmutableSet<CANDIDATE_TYPE> candidates) {
        Builder<CANDIDATE_TYPE, CandidateState<CANDIDATE_TYPE>> candidateStatesBuilder = ImmutableMap.builder();
        for (CANDIDATE_TYPE candidate : candidates) {
            candidateStatesBuilder.put(candidate, new CandidateState<>(candidate));
        }
        candidateStates = candidateStatesBuilder.build();
    }

    private CandidateStates(ImmutableMap<CANDIDATE_TYPE, CandidateState<CANDIDATE_TYPE>> candidateStates) {
        this.candidateStates = candidateStates;
    }

    public ImmutableSet<CANDIDATE_TYPE> getHopefulCandidates() {
        ImmutableSet.Builder<CANDIDATE_TYPE> builder = ImmutableSet.builder();
        candidateStates.entrySet().stream().filter(this::isHopefulCandidate)
                .forEach(entry -> builder.add(entry.getKey()));

        return builder.build();
    }

    private boolean isHopefulCandidate(Entry<CANDIDATE_TYPE, CandidateState<CANDIDATE_TYPE>> entry) {
        return (entry.getValue() != null) && entry.getValue().isHopeful();
    }

    public CandidateStates<CANDIDATE_TYPE> withElected(CANDIDATE_TYPE candidate) {
        return new CandidateStates<>(
                mapWithChangedEntry(candidateStates, candidate, candidateStates.get(candidate).asElected()));
    }

    public CandidateStates<CANDIDATE_TYPE> withLoser(CANDIDATE_TYPE candidate) {
        return new CandidateStates<>(
                mapWithChangedEntry(candidateStates, candidate, candidateStates.get(candidate).asLooser()));
    }

    public CandidateState<CANDIDATE_TYPE> getCandidateState(CANDIDATE_TYPE candidate) {
        return candidateStates.get(candidate);
    }

    @Override
    public Iterator<CandidateState<CANDIDATE_TYPE>> iterator() {
        return candidateStates.values().iterator();
    }

    @Override
    public String toString() {
        return candidateStates.toString();
    }

    private static <K, V, EK extends K, EV extends V> ImmutableMap<K, V> mapWithChangedEntry(ImmutableMap<K, V> map,
            EK changedKey, EV newValue) {
        Map<K, V> tmpMap = new HashMap<>(map);
        tmpMap.put(changedKey, newValue);
        return ImmutableMap.copyOf(tmpMap);
    }
}