KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > org > h2 > value > ValueString


1 /*
2  * Copyright 2004-2006 H2 Group. Licensed under the H2 License, Version 1.0 (http://h2database.com/html/license.html).
3  * Initial Developer: H2 Group
4  */
5 package org.h2.value;
6
7 import org.h2.engine.Constants;
8 import org.h2.util.StringCache;
9
10 /**
11  * @author Thomas
12  */
13 public class ValueString extends ValueStringBase {
14
15     private static final ValueString EMPTY = new ValueString("");
16
17     protected ValueString(String JavaDoc value) {
18         super(value);
19     }
20
21     public int getType() {
22         return Value.STRING;
23     }
24
25     protected int compareSecure(Value o, CompareMode mode) {
26         ValueString v = (ValueString) o;
27         return mode.compareString(value, v.value, false);
28     }
29
30     public int hashCode() {
31         // TODO hash performance: could build a quicker hash by hashing the size and a few characters
32 return value.hashCode();
33         
34         // proposed code:
35 // private int hash = 0;
36 //
37 // public int hashCode() {
38 // int h = hash;
39 // if (h == 0) {
40 // String s = value;
41 // int l = s.length();
42 // if (l > 0) {
43 // if (l < 16)
44 // h = s.hashCode();
45 // else {
46 // h = l;
47 // for (int i = 1; i <= l; i <<= 1)
48 // h = 31 * (31 * h + s.charAt(i - 1)) + s.charAt(l - i);
49 // }
50 // hash = h;
51 // }
52 // }
53 // return h;
54 // }
55
56     }
57
58     public static ValueString get(String JavaDoc s) {
59         if (s.length() == 0) {
60             return EMPTY;
61         }
62         ValueString obj = new ValueString(StringCache.get(s));
63         if (s.length() > Constants.OBJECT_CACHE_MAX_PER_ELEMENT_SIZE) {
64             return obj;
65         }
66         return (ValueString) Value.cache(obj);
67         // this saves memory, but is really slow
68 // return new ValueString(s.intern());
69 }
70
71 }
72
Popular Tags