io.grpc.internal.HedgingPolicy.java Source code

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Here is the source code for io.grpc.internal.HedgingPolicy.java

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/*
 * Copyright 2018 The gRPC Authors
 *
 * 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 io.grpc.internal;

import com.google.common.base.MoreObjects;
import com.google.common.base.Objects;
import com.google.common.collect.ImmutableSet;
import io.grpc.Status.Code;
import java.util.Collections;
import java.util.Set;
import javax.annotation.concurrent.Immutable;

/**
 * Hedging policy data object.
 */
@Immutable
final class HedgingPolicy {
    final int maxAttempts;
    final long hedgingDelayNanos;
    final Set<Code> nonFatalStatusCodes;

    /** No hedging. */
    static final HedgingPolicy DEFAULT = new HedgingPolicy(1, 0, Collections.<Code>emptySet());

    /**
     * The caller is supposed to have validated the arguments and handled throwing exception or
     * logging warnings already, so we avoid repeating args check here.
     */
    HedgingPolicy(int maxAttempts, long hedgingDelayNanos, Set<Code> nonFatalStatusCodes) {
        this.maxAttempts = maxAttempts;
        this.hedgingDelayNanos = hedgingDelayNanos;
        this.nonFatalStatusCodes = ImmutableSet.copyOf(nonFatalStatusCodes);
    }

    @Override
    public boolean equals(Object other) {
        if (this == other) {
            return true;
        }
        if (other == null || getClass() != other.getClass()) {
            return false;
        }
        HedgingPolicy that = (HedgingPolicy) other;
        return maxAttempts == that.maxAttempts && hedgingDelayNanos == that.hedgingDelayNanos
                && Objects.equal(nonFatalStatusCodes, that.nonFatalStatusCodes);
    }

    @Override
    public int hashCode() {
        return Objects.hashCode(maxAttempts, hedgingDelayNanos, nonFatalStatusCodes);
    }

    @Override
    public String toString() {
        return MoreObjects.toStringHelper(this).add("maxAttempts", maxAttempts)
                .add("hedgingDelayNanos", hedgingDelayNanos).add("nonFatalStatusCodes", nonFatalStatusCodes)
                .toString();
    }

    /**
     * Provides the most suitable hedging policy for a call.
     */
    interface Provider {

        /**
         * This method is used no more than once for each call. Never returns null.
         */
        HedgingPolicy get();
    }
}