001 /*
002 // $Id: //open/mondrian/src/main/mondrian/rolap/agg/DenseSegmentDataset.java#9 $
003 // This software is subject to the terms of the Common Public License
004 // Agreement, available at the following URL:
005 // http://www.opensource.org/licenses/cpl.html.
006 // Copyright (C) 2002-2002 Kana Software, Inc.
007 // Copyright (C) 2002-2007 Julian Hyde and others
008 // All Rights Reserved.
009 // You must accept the terms of that agreement to use this software.
010 //
011 // jhyde, 21 March, 2002
012 */
013 package mondrian.rolap.agg;
014
015 import mondrian.rolap.CellKey;
016
017 import java.util.Map;
018 import java.util.Iterator;
019
020 /**
021 * A <code>DenseSegmentDataset</code> is a means of storing segment values
022 * which is suitable when most of the combinations of keys have a value
023 * present.
024 *
025 * <p>The storage requirements are as follows. Table requires 1 word per
026 * cell.</p>
027 *
028 * @author jhyde
029 * @since 21 March, 2002
030 * @version $Id: //open/mondrian/src/main/mondrian/rolap/agg/DenseSegmentDataset.java#9 $
031 */
032 class DenseSegmentDataset implements SegmentDataset {
033 private final Segment segment;
034 private final Object[] values; // length == m[0] * ... * m[axes.length-1]
035
036 DenseSegmentDataset(Segment segment, Object[] values) {
037 this.segment = segment;
038 this.values = values;
039 }
040
041 public Object get(CellKey key) {
042 int offset = getOffset(key.getOrdinals());
043 return values[offset];
044 }
045
046 public double getBytes() {
047 // assume a slot, key, and value are each 4 bytes
048 return values.length * 12;
049 }
050
051 public void put(CellKey key, Object value) {
052 int offset = getOffset(key.getOrdinals());
053 values[offset] = value;
054 }
055
056 public Iterator<Map.Entry<CellKey, Object>> iterator() {
057 return new Itr();
058 }
059
060 boolean contains(Object[] keys) {
061 return getOffset(keys) >= 0;
062 }
063
064 Object get(Object[] keys) {
065 int offset = getOffset(keys);
066 return keys[offset];
067 }
068
069 void put(Object[] keys, Object value) {
070 int offset = getOffset(keys);
071 keys[offset] = value;
072 }
073
074 private int getOffset(int[] keys) {
075 int offset = 0;
076 for (int i = 0; i < keys.length; i++) {
077 Aggregation.Axis axis = segment.axes[i];
078 Object[] ks = axis.getKeys();
079 offset *= ks.length;
080 offset += keys[i];
081 }
082 return offset;
083 }
084
085 private int getOffset(Object[] keys) {
086 int offset = 0;
087 outer:
088 for (int i = 0; i < keys.length; i++) {
089 Aggregation.Axis axis = segment.axes[i];
090 Object[] ks = axis.getKeys();
091 offset *= ks.length;
092 Object value = keys[i];
093 for (int j = 0, axisLength = ks.length; j < axisLength; j++) {
094 if (ks[j].equals(value)) {
095 offset += j;
096 continue outer;
097 }
098 }
099 return -1; // not found
100 }
101 return offset;
102 }
103
104 void set(int k, Object o) {
105 values[k] = o;
106 }
107
108 /**
109 * Iterator over a DenseSegmentDataset.
110 *
111 * <p>This is a 'cheap' implementation
112 * which doesn't allocate a new Entry every step: it just returns itself.
113 * The Entry must therefore be used immediately, before calling
114 * {@link #next()} again.
115 */
116 private class Itr implements
117 Iterator<Map.Entry<CellKey, Object>>,
118 Map.Entry<CellKey, Object>
119 {
120 private int i = -1;
121 private final int[] ordinals;
122 private final CellKey key;
123
124 Itr() {
125 ordinals = new int[segment.axes.length];
126 ordinals[ordinals.length - 1] = -1;
127 key = CellKey.Generator.newRefCellKey(ordinals);
128 }
129
130 public boolean hasNext() {
131 return i < values.length - 1;
132 }
133
134 public Map.Entry<CellKey, Object> next() {
135 ++i;
136 int k = ordinals.length - 1;
137 while (k >= 0) {
138 if (ordinals[k] < segment.axes[k].getKeys().length - 1) {
139 ++ordinals[k];
140 break;
141 } else {
142 ordinals[k] = 0;
143 --k;
144 }
145 }
146 return this;
147 }
148
149 // implement Iterator
150 public void remove() {
151 throw new UnsupportedOperationException();
152 }
153
154 // implement Entry
155 public CellKey getKey() {
156 return key;
157 }
158
159 // implement Entry
160 public Object getValue() {
161 return values[i];
162 }
163
164 // implement Entry
165 public Object setValue(Object value) {
166 throw new UnsupportedOperationException();
167 }
168 }
169 }
170
171 // End DenseSegmentDataset.java