OrPredicate.java

/*
 * Copyright (c) 2008-2017, Hazelcast, Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.hazelcast.query.impl.predicates;

import com.hazelcast.nio.ObjectDataInput;
import com.hazelcast.nio.ObjectDataOutput;
import com.hazelcast.nio.serialization.IdentifiedDataSerializable;
import com.hazelcast.nio.serialization.BinaryInterface;
import com.hazelcast.query.IndexAwarePredicate;
import com.hazelcast.query.Predicate;
import com.hazelcast.query.VisitablePredicate;
import com.hazelcast.query.impl.Indexes;
import com.hazelcast.query.impl.OrResultSet;
import com.hazelcast.query.impl.QueryContext;
import com.hazelcast.query.impl.QueryableEntry;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;

import java.io.IOException;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;

import static com.hazelcast.internal.serialization.impl.FactoryIdHelper.PREDICATE_DS_FACTORY_ID;

/**
 * Or Predicate
 */
@BinaryInterface
public final class OrPredicate
        implements IndexAwarePredicate, VisitablePredicate, NegatablePredicate, IdentifiedDataSerializable, CompoundPredicate {

    protected Predicate[] predicates;

    public OrPredicate() {
    }

    public OrPredicate(Predicate... predicates) {
        this.predicates = predicates;
    }

    @Override
    public Set<QueryableEntry> filter(QueryContext queryContext) {
        List<Set<QueryableEntry>> indexedResults = new LinkedList<Set<QueryableEntry>>();
        for (Predicate predicate : predicates) {
            if (predicate instanceof IndexAwarePredicate) {
                IndexAwarePredicate iap = (IndexAwarePredicate) predicate;
                if (iap.isIndexed(queryContext)) {
                    Set<QueryableEntry> s = iap.filter(queryContext);
                    if (s != null) {
                        indexedResults.add(s);
                    }
                } else {
                    return null;
                }
            }
        }
        return indexedResults.isEmpty() ? null : new OrResultSet(indexedResults);
    }

    @Override
    public boolean isIndexed(QueryContext queryContext) {
        for (Predicate predicate : predicates) {
            if (predicate instanceof IndexAwarePredicate) {
                IndexAwarePredicate iap = (IndexAwarePredicate) predicate;
                if (!iap.isIndexed(queryContext)) {
                    return false;
                }
            } else {
                return false;
            }
        }
        return true;
    }

    @Override
    public boolean apply(Map.Entry mapEntry) {
        for (Predicate predicate : predicates) {
            if (predicate.apply(mapEntry)) {
                return true;
            }
        }
        return false;
    }


    @Override
    public void writeData(ObjectDataOutput out) throws IOException {
        out.writeInt(predicates.length);
        for (Predicate predicate : predicates) {
            out.writeObject(predicate);
        }
    }

    @Override
    public void readData(ObjectDataInput in) throws IOException {
        int size = in.readInt();
        predicates = new Predicate[size];
        for (int i = 0; i < size; i++) {
            predicates[i] = in.readObject();
        }
    }

    @Override
    public String toString() {
        final StringBuilder sb = new StringBuilder();
        sb.append("(");
        int size = predicates.length;
        for (int i = 0; i < size; i++) {
            if (i > 0) {
                sb.append(" OR ");
            }
            sb.append(predicates[i]);
        }
        sb.append(")");
        return sb.toString();
    }

    @Override
    public Predicate accept(Visitor visitor, Indexes indexes) {
        Predicate[] result = VisitorUtils.acceptVisitor(predicates, visitor, indexes);
        if (result != predicates) {
            return visitor.visit(new OrPredicate(result), indexes);
        }
        return visitor.visit(this, indexes);
    }

    @Override
    public Predicate negate() {
        int size = predicates.length;
        Predicate[] inners = new Predicate[size];
        for (int i = 0; i < size; i++) {
            Predicate original = predicates[i];
            Predicate negated;
            if (original instanceof NegatablePredicate) {
                negated = ((NegatablePredicate) original).negate();
            } else {
                negated = new NotPredicate(original);
            }
            inners[i] = negated;
        }
        AndPredicate andPredicate = new AndPredicate(inners);
        return andPredicate;
    }

    @Override
    public int getFactoryId() {
        return PREDICATE_DS_FACTORY_ID;
    }

    @Override
    public int getId() {
        return PredicateDataSerializerHook.OR_PREDICATE;
    }

    /**
     * Visitable predicates are treated as effectively immutable, therefore callers should not make any changes to
     * the returned array.
     */
    @Override
    @SuppressFBWarnings("EI_EXPOSE_REP")
    public <K, V> Predicate<K, V>[] getPredicates() {
        return predicates;
    }

    /**
     * Visitable predicates are treated as effectively immutable, therefore callers should not make any changes to
     * the array passed as argument after is has been set.
     * @param predicates    the array of sub-predicates for this {@code Or} operator. It is not safe to make any changes to
     *                      this array after it has been set.
     */
    @Override
    @SuppressFBWarnings("EI_EXPOSE_REP")
    public <K, V> void setPredicates(Predicate<K, V>[] predicates) {
        if (this.predicates == null) {
            this.predicates = predicates;
        } else {
            throw new IllegalStateException("Cannot reset predicates in an OrPredicate after they have been already set.");
        }
    }
}