org.apache.lens.server.query.constraint.DefaultQueryLaunchingConstraintsChecker.java Source code

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Here is the source code for org.apache.lens.server.query.constraint.DefaultQueryLaunchingConstraintsChecker.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.lens.server.query.constraint;

import java.util.Collections;
import java.util.Set;

import org.apache.lens.server.api.query.QueryContext;
import org.apache.lens.server.api.query.collect.EstimatedImmutableQueryCollection;
import org.apache.lens.server.api.query.constraint.QueryLaunchingConstraint;
import org.apache.lens.server.api.retry.BackOffRetryHandler;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Sets;
import lombok.NonNull;
import lombok.extern.slf4j.Slf4j;

/**
 *
 * This {@link QueryLaunchingConstraintsChecker} enforces that a candidate query will be allowed to launch only if
 * all {@link QueryLaunchingConstraint}s of lens server and all {@link QueryLaunchingConstraint}s of driver selected
 * for query allow the query to be launched.
 *
 */
@Slf4j
public class DefaultQueryLaunchingConstraintsChecker implements QueryLaunchingConstraintsChecker {

    private final ImmutableSet<QueryLaunchingConstraint> lensQueryConstraints;

    public DefaultQueryLaunchingConstraintsChecker(
            @NonNull final ImmutableSet<QueryLaunchingConstraint> lensQueryConstraints) {
        this.lensQueryConstraints = lensQueryConstraints;
    }

    @Override
    public boolean canLaunch(final QueryContext candidateQuery,
            final EstimatedImmutableQueryCollection launchedQueries) {

        Set<QueryLaunchingConstraint> allConstraints = prepareAllConstraints(candidateQuery);

        for (QueryLaunchingConstraint queryConstraint : allConstraints) {
            String launchRejectionMessage = queryConstraint.allowsLaunchOf(candidateQuery, launchedQueries);
            if (launchRejectionMessage != null) {
                log.info("query {} not allowed to launch. Constraint failed: {} with message: {}", candidateQuery,
                        queryConstraint, launchRejectionMessage);
                candidateQuery.getStatus().setProgressMessage(launchRejectionMessage);
                return false;
            }
        }
        return true;
    }

    @VisibleForTesting
    Set<QueryLaunchingConstraint> prepareAllConstraints(final QueryContext candidateQuery) {

        ImmutableSet<QueryLaunchingConstraint> driverConstraints = candidateQuery
                .getSelectedDriverQueryConstraints();
        BackOffRetryHandler<QueryContext> retryPolicy = candidateQuery.getRetryPolicy();
        Sets.SetView<QueryLaunchingConstraint> constraints = Sets.union(this.lensQueryConstraints,
                driverConstraints);
        if (retryPolicy == null) {
            return constraints;
        } else {
            return Sets.union(Collections.singleton(new RetryPolicyToConstraingAdapter(retryPolicy)), constraints);
        }
    }
}