densesegmentdataset.java

来自「数据仓库展示程序」· Java 代码 · 共 91 行

/*
// $Id: //open/mondrian/src/main/mondrian/rolap/agg/DenseSegmentDataset.java#5 $
// (C) Copyright 2002-2005 Kana Software, Inc.
// This software is subject to the terms of the Common Public License
// Agreement, available at the following URL:
// http://www.opensource.org/licenses/cpl.html.
// (C) Copyright 2002-2005 Kana Software, Inc. and others.
// All Rights Reserved.
// You must accept the terms of that agreement to use this software.
//
// jhyde, 21 March, 2002
*/
package mondrian.rolap.agg;

import mondrian.rolap.CellKey;

/**
 * A <code>DenseSegmentDataset</code> is a means of storing segment values
 * which is suitable when most of the combinations of keys have a value
 * present.
 *
 * <p>The storage requirements are as follows. Table requires 1 word per
 * cell.</p>
 *
 * @author jhyde
 * @since 21 March, 2002
 * @version $Id: //open/mondrian/src/main/mondrian/rolap/agg/DenseSegmentDataset.java#5 $
 **/
class DenseSegmentDataset implements SegmentDataset {
    private final Segment segment;
    private final Object[] values; // length == m[0] * ... * m[axes.length-1]

    DenseSegmentDataset(Segment segment, Object[] values) {
        this.segment = segment;
        this.values = values;
    }
    public Object get(CellKey keys) {
        int offset = getOffset(keys.ordinals);
        return values[offset];
    }
    public double getBytes() {
        // assume a slot, key, and value are each 4 bytes
        return values.length * 12;
    }
    boolean contains(Object[] keys) {
        return (getOffset(keys) >= 0);
    }
    Object get(Object[] keys) {
        int offset = getOffset(keys);
        return keys[offset];
    }
    void put(Object[] keys, Object value) {
        int offset = getOffset(keys);
        keys[offset] = value;
    }
    private int getOffset(int[] keys) {
        int offset = 0;
        for (int i = 0; i < keys.length; i++) {
            Aggregation.Axis axis = segment.axes[i];
            Object[] ks = axis.getKeys();
            offset *= ks.length;
            offset += keys[i];
        }
        return offset;
    }
    private int getOffset(Object[] keys) {
        int offset = 0;
outer:
        for (int i = 0; i < keys.length; i++) {
            Aggregation.Axis axis = segment.axes[i];
            Object[] ks = axis.getKeys();
            offset *= ks.length;
            Object value = keys[i];
            for (int j = 0, axisLength = ks.length; j < axisLength; j++) {
                if (ks[j].equals(value)) {
                    offset += j;
                    continue outer;
                }
            }
            return -1; // not found
        }
        return offset;
    }

    void set(int k, Object o) {
        values[k] = o;
    }
}

// End DenseSegmentDataset.java