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1
11 package org.eclipse.core.internal.registry;
12
13 import java.io.*;
14
15
18 public final class HashtableOfStringAndInt implements Cloneable  {
19 public static final int MISSING_ELEMENT = Integer.MIN_VALUE;
20
21 private String keyTable[];
23 private int valueTable[];
24
25 private int elementSize; private int threshold;
27 private static final float GROWTH_FACTOR = 1.33f;
28
29 public HashtableOfStringAndInt() {
30 this(13);
31 }
32
33 public HashtableOfStringAndInt(int size) {
34 this.elementSize = 0;
35 this.threshold = size; int extraRoom = (int) (size * 1.75f);
37 if (this.threshold == extraRoom)
38 extraRoom++;
39 this.keyTable = new String [extraRoom];
40 this.valueTable = new int[extraRoom];
41 }
42
43 public Object clone() throws CloneNotSupportedException {
44 throw new CloneNotSupportedException ();
45 }
58
59 public boolean containsKey(String key) {
60 int index = (key.hashCode() & 0x7FFFFFFF) % valueTable.length;
61 int keyLength = key.length();
62 String currentKey;
63 while ((currentKey = keyTable[index]) != null) {
64 if (currentKey.length() == keyLength && currentKey.equals(key))
65 return true;
66 index = (index + 1) % keyTable.length;
67 }
68 return false;
69 }
70
71 public int get(String key) {
72 int index = (key.hashCode() & 0x7FFFFFFF) % valueTable.length;
73 int keyLength = key.length();
74 String currentKey;
75 while ((currentKey = keyTable[index]) != null) {
76 if (currentKey.length() == keyLength && currentKey.equals(key))
77 return valueTable[index];
78 index = (index + 1) % keyTable.length;
79 }
80 return MISSING_ELEMENT;
81 }
82
83 public int put(String key, int value) {
84 int index = (key.hashCode() & 0x7FFFFFFF) % valueTable.length;
85 int keyLength = key.length();
86 String currentKey;
87 while ((currentKey = keyTable[index]) != null) {
88 if (currentKey.length() == keyLength && currentKey.equals(key))
89 return valueTable[index] = value;
90 index = (index + 1) % keyTable.length;
91 }
92 keyTable[index] = key;
93 valueTable[index] = value;
94
95 if (++elementSize > threshold)
97 rehash();
98 return value;
99 }
100
101 public int removeKey(String key) {
102 int index = (key.hashCode() & 0x7FFFFFFF) % valueTable.length;
103 int keyLength = key.length();
104 String currentKey;
105 while ((currentKey = keyTable[index]) != null) {
106 if (currentKey.length() == keyLength && currentKey.equals(key)) {
107 int value = valueTable[index];
108 elementSize--;
109 keyTable[index] = null;
110 valueTable[index] = MISSING_ELEMENT;
111 rehash();
112 return value;
113 }
114 index = (index + 1) % keyTable.length;
115 }
116 return MISSING_ELEMENT;
117 }
118
119 private void rehash() {
120 HashtableOfStringAndInt newHashtable = new HashtableOfStringAndInt((int) (elementSize * GROWTH_FACTOR));
121 String currentKey;
122 for (int i = keyTable.length; --i >= 0;)
123 if ((currentKey = keyTable[i]) != null)
124 newHashtable.put(currentKey, valueTable[i]);
125
126 this.keyTable = newHashtable.keyTable;
127 this.valueTable = newHashtable.valueTable;
128 this.threshold = newHashtable.threshold;
129 }
130
131 public int size() {
132 return elementSize;
133 }
134
135 public String toString() {
136 String s = ""; int object;
138 for (int i = 0, length = valueTable.length; i < length; i++)
139 if ((object = valueTable[i]) != MISSING_ELEMENT)
140 s += new String (keyTable[i]) + " -> " + object + "\n"; return s;
142 }
143
144 public int[] getValues() {
145 int keyTableLength = keyTable.length;
146 int[] result = new int[size()];
147 int j = 0;
148 for (int i = 0; i < keyTableLength; i++) {
149 if (keyTable[i] != null)
150 result[j++] = valueTable[i];
151 }
152 return result;
153 }
154
155 public void save(DataOutputStream out) throws IOException {
156 out.writeInt(elementSize);
157 int tableSize = keyTable.length;
158 out.writeInt(tableSize);
159 out.writeInt(threshold);
160 for (int i = 0; i < tableSize; i++) {
161 writeStringOrNull(keyTable[i], out);
162 out.writeInt(valueTable[i]);
163 }
164 }
165
166
169 public void save(DataOutputStream out, RegistryObjectManager objectManager) throws IOException {
170 HashtableOfStringAndInt filteredHashtable = new HashtableOfStringAndInt((int) (elementSize * GROWTH_FACTOR));
171 String currentKey;
172 for (int i = keyTable.length; --i >= 0;)
173 if ((currentKey = keyTable[i]) != null && objectManager.shouldPersist(valueTable[i]))
174 filteredHashtable.put(currentKey, valueTable[i]);
175 filteredHashtable.save(out);
176 }
177
178 public void load(DataInputStream in) throws IOException {
179 elementSize = in.readInt();
180 int tableSize = in.readInt();
181 threshold = in.readInt();
182 boolean fastMode = true;
183 if (((double) tableSize / elementSize) < GROWTH_FACTOR) {
184 keyTable = new String [(int) (elementSize * GROWTH_FACTOR)];
185 valueTable = new int[(int) (elementSize * GROWTH_FACTOR)];
186 elementSize = 0;
187 fastMode = false;
188 } else {
189 keyTable = new String [tableSize];
190 valueTable = new int[tableSize];
191 }
192 for (int i = 0; i < tableSize; i++) {
193 String key = readStringOrNull(in);
194 int value = in.readInt();
195 if (fastMode) {
196 keyTable[i] = key;
197 valueTable[i] = value;
198 } else {
199 if (key != null)
200 put(key, value);
201 }
202 }
203 }
204
205 private static final byte NULL = 0;
206 private static final byte OBJECT = 1;
207
208 private void writeStringOrNull(String string, DataOutputStream out) throws IOException {
209 if (string == null)
210 out.writeByte(NULL);
211 else {
212 out.writeByte(OBJECT);
213 out.writeUTF(string);
214 }
215 }
216
217 private String readStringOrNull(DataInputStream in) throws IOException {
218 byte type = in.readByte();
219 if (type == NULL)
220 return null;
221 return in.readUTF();
222 }
223
224 }
225 |
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