1/*- 2 * See the file LICENSE for redistribution information. 3 * 4 * Copyright (c) 2000-2009 Oracle. All rights reserved. 5 * 6 * $Id$ 7 */ 8 9package com.sleepycat.bind.tuple; 10 11import com.sleepycat.db.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.db} 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 */ 33public class FloatBinding extends TupleBinding<Float> { 34 35 private static final int FLOAT_SIZE = 4; 36 37 // javadoc is inherited 38 public Float entryToObject(TupleInput input) { 39 40 return input.readFloat(); 41 } 42 43 // javadoc is inherited 44 public void objectToEntry(Float object, TupleOutput output) { 45 46 output.writeFloat(object); 47 } 48 49 // javadoc is inherited 50 protected TupleOutput getTupleOutput(Float 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} 88