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Java > Open Source Codes > com > versant > core > jdbc > sql > conv > DoubleArrayConverter


1
2 /*
3  * Copyright (c) 1998 - 2005 Versant Corporation
4  * All rights reserved. This program and the accompanying materials
5  * are made available under the terms of the Eclipse Public License v1.0
6  * which accompanies this distribution, and is available at
7  * http://www.eclipse.org/legal/epl-v10.html
8  *
9  * Contributors:
10  * Versant Corporation - initial API and implementation
11  */
12 package com.versant.core.jdbc.sql.conv;
13
14 import com.versant.core.jdbc.JdbcConverter;
15
16 /**
17  * This converter converts double[] to and from SQL. It converts the double[]
18  * to and from a double[] and delegates to a nested converter.
19  * TODO This could be done much faster with java.nio buffers.
20  * @keep-all
21  */
22 public class DoubleArrayConverter extends TypeAsBytesConverterBase {
23
24     public static class Factory extends TypeAsBytesConverterBase.Factory {
25
26         protected JdbcConverter createConverter(JdbcConverter nested) {
27             return new DoubleArrayConverter(nested);
28         }
29
30     }
31
32     public DoubleArrayConverter(JdbcConverter nested) {
33         super(nested);
34     }
35
36     /**
37      * Convert a byte[] into an instance of our value class.
38      */
39     protected Object JavaDoc fromByteArray(byte[] buf) {
40         int n = buf.length / 8;
41         double[] a = new double[n];
42         int i = 0, j = 0;
43         for (; i < n; ) {
44             a[i++] = Double.longBitsToDouble(
45                       ((long)(buf[j++] & 0xFF) << 56)
46                     + ((long)(buf[j++] & 0xFF) << 48)
47                     + ((long)(buf[j++] & 0xFF) << 40)
48                     + ((long)(buf[j++] & 0xFF) << 32)
49                     + ((long)(buf[j++] & 0xFF) << 24)
50                     + ((buf[j++] & 0xFF) << 16)
51                     + ((buf[j++] & 0xFF) << 8)
52                     + (buf[j++] & 0xFF));
53         }
54         return a;
55     }
56
57     /**
58      * Convert an instance of our value class into a byte[].
59      */
60     protected byte[] toByteArray(Object JavaDoc value) {
61         if (value == null) return null;
62         double[] a = (double[])value;
63         int n = a.length;
64         byte[] buf = new byte[n * 8];
65         int i = 0, j = 0;
66         for (; i < n; ) {
67
68             long x = Double.doubleToRawLongBits(a[i++]);
69
70
71             buf[j++] = (byte)((x >>> 56) & 0xFF);
72             buf[j++] = (byte)((x >>> 48) & 0xFF);
73             buf[j++] = (byte)((x >>> 40) & 0xFF);
74             buf[j++] = (byte)((x >>> 32) & 0xFF);
75             buf[j++] = (byte)((x >>> 24) & 0xFF);
76             buf[j++] = (byte)((x >>> 16) & 0xFF);
77             buf[j++] = (byte)((x >>> 8) & 0xFF);
78             buf[j++] = (byte)(x & 0xFF);
79         }
80         return buf;
81     }
82
83     /**
84      * Get the type of our expected value objects (e.g. java.util.Locale
85      * for a converter for Locale's).
86      */
87     public Class JavaDoc getValueType() {
88         return double[].class;
89     }
90
91 }
92
93
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