phoenix-core/src/main/java/org/apache/phoenix/schema/stats/GuidePostsInfo.java

/*
 * 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.phoenix.schema.stats;

import java.util.ArrayList;
import java.util.List;

import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.phoenix.util.ByteUtil;
import org.apache.phoenix.util.SizedUtil;

import com.google.common.primitives.Longs;
/**
 *  A class that holds the guidePosts of a region and also allows combining the 
 *  guidePosts of different regions when the GuidePostsInfo is formed for a table.
 */
public class GuidePostsInfo {
    public final static GuidePostsInfo EMPTY_GUIDEPOST = new GuidePostsInfo(new ArrayList<Long>(),
            new ImmutableBytesWritable(ByteUtil.EMPTY_BYTE_ARRAY), new ArrayList<Long>(), 0, 0) {
        @Override
        public int getEstimatedSize() {
            return 0;
        }
    };
    public final static GuidePostsInfo NO_GUIDEPOST = new GuidePostsInfo(new ArrayList<Long>(),
            new ImmutableBytesWritable(ByteUtil.EMPTY_BYTE_ARRAY), new ArrayList<Long>(), 0, 0) {
        @Override
        public int getEstimatedSize() {
            return 0;
        }
    };

    /**
     * the total number of guidePosts for the table combining all the guidePosts per region per cf.
     */
    private final ImmutableBytesWritable guidePosts;
    /**
     * Maximum length of a guidePost collected
     */
    private final int maxLength;
    /**
     * Number of guidePosts
     */
    private final int guidePostsCount;
    /**
     * The rowCounts of each guidePost traversed
     */
    private final long[] rowCounts;
    /**
     * The bytecounts of each guidePost traversed
     */
    private final long[] byteCounts;
    /**
     * Estimate of byte size of this instance
     */
    private final int estimatedSize;

    /**
     * Constructor that creates GuidePostsInfo per region
     * 
     * @param byteCounts
     *            The bytecounts of each guidePost traversed
     * @param guidePosts
     *            Prefix byte encoded guidePosts
     * @param rowCounts
     *            The rowCounts of each guidePost traversed
     * @param maxLength
     *            Maximum length of a guidePost collected
     * @param guidePostsCount
     *            Number of guidePosts
     */
    public GuidePostsInfo(List<Long> byteCounts, ImmutableBytesWritable guidePosts, List<Long> rowCounts, int maxLength,
            int guidePostsCount) {
        this.guidePosts = new ImmutableBytesWritable(guidePosts);
        this.maxLength = maxLength;
        this.guidePostsCount = guidePostsCount;
        this.rowCounts = Longs.toArray(rowCounts);
        this.byteCounts = Longs.toArray(byteCounts);
        int estimatedSize = SizedUtil.OBJECT_SIZE 
                + SizedUtil.IMMUTABLE_BYTES_WRITABLE_SIZE + guidePosts.getLength() // guidePosts
                + SizedUtil.INT_SIZE // maxLength
                + SizedUtil.INT_SIZE // guidePostsCount
                + SizedUtil.ARRAY_SIZE + this.rowCounts.length * SizedUtil.LONG_SIZE // rowCounts
                + SizedUtil.ARRAY_SIZE + this.byteCounts.length * SizedUtil.LONG_SIZE // byteCounts
                + SizedUtil.INT_SIZE; // estimatedSize
        this.estimatedSize = estimatedSize;
    }
    
    public ImmutableBytesWritable getGuidePosts() {
        return guidePosts;
    }

    public int getGuidePostsCount() {
        return guidePostsCount;
    }
    
    public int getMaxLength() {
        return maxLength;
    }

    public long[] getRowCounts() {
        return rowCounts;
    }

    public long[] getByteCounts() {
        return byteCounts;
    }

    public int getEstimatedSize() {
        return estimatedSize;
    }
}