01: /*-
02: * See the file LICENSE for redistribution information.
03: *
04: * Copyright (c) 2000,2008 Oracle. All rights reserved.
05: *
06: * $Id: FloatBinding.java,v 1.11.2.2 2008/01/07 15:14:06 cwl Exp $
07: */
08:
09: package com.sleepycat.bind.tuple;
10:
11: import com.sleepycat.je.DatabaseEntry;
12:
13: /**
14: * A concrete <code>TupleBinding</code> for a <code>Float</code> primitive
15: * wrapper or a <code>float</code> primitive.
16: *
17: * <p><em>Note:</em> This class produces byte array values that by default
18: * (without a custom comparator) do <em>not</em> sort correctly for negative
19: * values. Only non-negative values are sorted correctly by default. To sort
20: * all values correctly by default, use {@link SortedFloatBinding}.</p>
21: *
22: * <p>There are two ways to use this class:</p>
23: * <ol>
24: * <li>When using the {@link com.sleepycat.je} package directly, the static
25: * methods in this class can be used to convert between primitive values and
26: * {@link DatabaseEntry} objects.</li>
27: * <li>When using the {@link com.sleepycat.collections} package, an instance of
28: * this class can be used with any stored collection. The easiest way to
29: * obtain a binding instance is with the {@link
30: * TupleBinding#getPrimitiveBinding} method.</li>
31: * </ol>
32: */
33: public class FloatBinding extends TupleBinding {
34:
35: private static final int FLOAT_SIZE = 4;
36:
37: // javadoc is inherited
38: public Object entryToObject(TupleInput input) {
39:
40: return new Float(input.readFloat());
41: }
42:
43: // javadoc is inherited
44: public void objectToEntry(Object object, TupleOutput output) {
45:
46: output.writeFloat(((Number) object).floatValue());
47: }
48:
49: // javadoc is inherited
50: protected TupleOutput getTupleOutput(Object object) {
51:
52: return sizedOutput();
53: }
54:
55: /**
56: * Converts an entry buffer into a simple <code>float</code> value.
57: *
58: * @param entry is the source entry buffer.
59: *
60: * @return the resulting value.
61: */
62: public static float entryToFloat(DatabaseEntry entry) {
63:
64: return entryToInput(entry).readFloat();
65: }
66:
67: /**
68: * Converts a simple <code>float</code> value into an entry buffer.
69: *
70: * @param val is the source value.
71: *
72: * @param entry is the destination entry buffer.
73: */
74: public static void floatToEntry(float val, DatabaseEntry entry) {
75:
76: outputToEntry(sizedOutput().writeFloat(val), entry);
77: }
78:
79: /**
80: * Returns a tuple output object of the exact size needed, to avoid
81: * wasting space when a single primitive is output.
82: */
83: static TupleOutput sizedOutput() {
84:
85: return new TupleOutput(new byte[FLOAT_SIZE]);
86: }
87: }
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