com.google.caliper.model.Host.java Source code

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Here is the source code for com.google.caliper.model.Host.java

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/*
 * Copyright (C) 2012 Google Inc.
 *
 * 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.google.caliper.model;

import static com.google.caliper.model.PersistentHashing.getPersistentHashFunction;
import static com.google.common.base.Preconditions.checkNotNull;
import static javax.persistence.AccessType.FIELD;
import static org.hibernate.annotations.SortType.NATURAL;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Objects;
import com.google.common.collect.ImmutableSortedMap;
import com.google.common.collect.Maps;
import com.google.common.hash.Funnel;
import com.google.common.hash.HashFunction;
import com.google.common.hash.PrimitiveSink;

import org.hibernate.annotations.Immutable;
import org.hibernate.annotations.Index;
import org.hibernate.annotations.Sort;

import java.util.Map;
import java.util.SortedMap;
import java.util.logging.Logger;

import javax.persistence.Access;
import javax.persistence.Cacheable;
import javax.persistence.ElementCollection;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.NamedQuery;
import javax.persistence.PrePersist;
import javax.persistence.PreUpdate;
import javax.persistence.QueryHint;

/**
 * The performance-informing properties of the host on which a benchmark is run.
 *
 * @author gak@google.com (Gregory Kick)
 */
@Entity
@Access(FIELD)
@Immutable
@Cacheable
@NamedQuery(name = "listHostsForHash", query = "SELECT h FROM Host h WHERE hash = :hash", hints = {
        @QueryHint(name = "org.hibernate.cacheable", value = "true"),
        @QueryHint(name = "org.hibernate.readOnly", value = "true") })
public final class Host {
    static final Host DEFAULT = new Host();
    private static final Logger logger = Logger.getLogger(Host.class.getName());

    @Id
    @GeneratedValue
    @ExcludeFromJson
    private int id;
    @ElementCollection
    @Sort(type = NATURAL)
    private SortedMap<String, String> properties;
    @ExcludeFromJson
    @Index(name = "hash_index")
    private int hash;

    private Host() {
        this.properties = Maps.newTreeMap();
    }

    private Host(Builder builder) {
        this.properties = Maps.newTreeMap(builder.properties);
        // eagerly initialize hash to allow for the test-only hash function
        initHash(builder.hashFunction);
    }

    public ImmutableSortedMap<String, String> properties() {
        return ImmutableSortedMap.copyOf(properties);
    }

    @Override
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        } else if (obj instanceof Host) {
            Host that = (Host) obj;
            return this.properties.equals(that.properties);
        } else {
            return false;
        }
    }

    private void initHash(HashFunction hashFunction) {
        if (hash == 0) {
            this.hash = hashFunction.hashObject(this, HostFunnel.INSTANCE).asInt();
        }
    }

    @PrePersist
    @PreUpdate
    private void initHash() {
        initHash(getPersistentHashFunction());
    }

    @Override
    public int hashCode() {
        initHash();
        return hash;
    }

    @Override
    public String toString() {
        return Objects.toStringHelper(this).add("properties", properties).toString();
    }

    enum HostFunnel implements Funnel<Host> {
        INSTANCE;

        @Override
        public void funnel(Host from, PrimitiveSink into) {
            StringMapFunnel.INSTANCE.funnel(from.properties, into);
        }
    }

    public static final class Builder {
        private final SortedMap<String, String> properties = Maps.newTreeMap();
        private HashFunction hashFunction = getPersistentHashFunction();

        public Builder addProperty(String key, String value) {
            properties.put(key, value);
            return this;
        }

        public Builder addAllProperies(Map<String, String> properties) {
            this.properties.putAll(properties);
            return this;
        }

        /**
         * This only exists for tests to induce hash collisions. Only use this in test code as changing
         * the hash function will break persisted objects.
         */
        @VisibleForTesting
        public Builder hashFunctionForTesting(HashFunction hashFunction) {
            logger.warning("somebody is setting the hash function. this should only be used in tests");
            this.hashFunction = checkNotNull(hashFunction);
            return this;
        }

        public Host build() {
            return new Host(this);
        }
    }
}