ch.ethz.system.mt.tpch.Distribution.java Source code

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Here is the source code for ch.ethz.system.mt.tpch.Distribution.java

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/*
 * 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 ch.ethz.system.mt.tpch;

import com.google.common.base.Objects;
import com.google.common.collect.ImmutableList;

import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;

public class Distribution {
    private final String name;
    private final List<String> values;
    private final int[] weights;
    private final String[] distribution;
    private final int maxWeight;

    public Distribution(String name, Map<String, Integer> distribution) {
        this.name = checkNotNull(name, "name is null");
        checkNotNull(distribution, "distribution is null");

        ImmutableList.Builder<String> values = ImmutableList.builder();
        this.weights = new int[distribution.size()];

        int runningWeight = 0;
        int index = 0;
        boolean isValidDistribution = true;
        for (Entry<String, Integer> entry : distribution.entrySet()) {
            values.add(entry.getKey());

            runningWeight += entry.getValue();
            weights[index] = runningWeight;

            isValidDistribution = isValidDistribution && entry.getValue() > 0;

            index++;
        }
        this.values = values.build();

        // "nations" is hack and not a valid distribution so we need to skip it
        if (isValidDistribution) {
            this.maxWeight = weights[weights.length - 1];
            this.distribution = new String[maxWeight];

            index = 0;
            for (String value : this.values) {
                int count = distribution.get(value);
                for (int i = 0; i < count; i++) {
                    this.distribution[index++] = value;
                }
            }
        } else {
            this.maxWeight = -1;
            this.distribution = null;
        }
    }

    public String getValue(int index) {
        return values.get(index);
    }

    public List<String> getValues() {
        return values;
    }

    public int getWeight(int index) {
        return weights[index];
    }

    public int size() {
        return values.size();
    }

    public String randomValue(RandomInt randomInt) {
        checkState(distribution != null, "%s does not have a distribution", name);

        int randomValue = randomInt.nextInt(0, maxWeight - 1);
        return distribution[randomValue];
    }

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