1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/emul/compact/src/main/java/java/math/MathContext.java Sat Sep 07 13:51:24 2013 +0200
1.3 @@ -0,0 +1,326 @@
1.4 +/*
1.5 + * Copyright (c) 2003, 2007, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation. Oracle designates this
1.11 + * particular file as subject to the "Classpath" exception as provided
1.12 + * by Oracle in the LICENSE file that accompanied this code.
1.13 + *
1.14 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.15 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.16 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.17 + * version 2 for more details (a copy is included in the LICENSE file that
1.18 + * accompanied this code).
1.19 + *
1.20 + * You should have received a copy of the GNU General Public License version
1.21 + * 2 along with this work; if not, write to the Free Software Foundation,
1.22 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.23 + *
1.24 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.25 + * or visit www.oracle.com if you need additional information or have any
1.26 + * questions.
1.27 + */
1.28 +
1.29 +/*
1.30 + * Portions Copyright IBM Corporation, 1997, 2001. All Rights Reserved.
1.31 + */
1.32 +
1.33 +package java.math;
1.34 +import java.io.*;
1.35 +
1.36 +/**
1.37 + * Immutable objects which encapsulate the context settings which
1.38 + * describe certain rules for numerical operators, such as those
1.39 + * implemented by the {@link BigDecimal} class.
1.40 + *
1.41 + * <p>The base-independent settings are:
1.42 + * <ol>
1.43 + * <li>{@code precision}:
1.44 + * the number of digits to be used for an operation; results are
1.45 + * rounded to this precision
1.46 + *
1.47 + * <li>{@code roundingMode}:
1.48 + * a {@link RoundingMode} object which specifies the algorithm to be
1.49 + * used for rounding.
1.50 + * </ol>
1.51 + *
1.52 + * @see BigDecimal
1.53 + * @see RoundingMode
1.54 + * @author Mike Cowlishaw
1.55 + * @author Joseph D. Darcy
1.56 + * @since 1.5
1.57 + */
1.58 +
1.59 +public final class MathContext implements Serializable {
1.60 +
1.61 + /* ----- Constants ----- */
1.62 +
1.63 + // defaults for constructors
1.64 + private static final int DEFAULT_DIGITS = 9;
1.65 + private static final RoundingMode DEFAULT_ROUNDINGMODE = RoundingMode.HALF_UP;
1.66 + // Smallest values for digits (Maximum is Integer.MAX_VALUE)
1.67 + private static final int MIN_DIGITS = 0;
1.68 +
1.69 + // Serialization version
1.70 + private static final long serialVersionUID = 5579720004786848255L;
1.71 +
1.72 + /* ----- Public Properties ----- */
1.73 + /**
1.74 + * A {@code MathContext} object whose settings have the values
1.75 + * required for unlimited precision arithmetic.
1.76 + * The values of the settings are:
1.77 + * <code>
1.78 + * precision=0 roundingMode=HALF_UP
1.79 + * </code>
1.80 + */
1.81 + public static final MathContext UNLIMITED =
1.82 + new MathContext(0, RoundingMode.HALF_UP);
1.83 +
1.84 + /**
1.85 + * A {@code MathContext} object with a precision setting
1.86 + * matching the IEEE 754R Decimal32 format, 7 digits, and a
1.87 + * rounding mode of {@link RoundingMode#HALF_EVEN HALF_EVEN}, the
1.88 + * IEEE 754R default.
1.89 + */
1.90 + public static final MathContext DECIMAL32 =
1.91 + new MathContext(7, RoundingMode.HALF_EVEN);
1.92 +
1.93 + /**
1.94 + * A {@code MathContext} object with a precision setting
1.95 + * matching the IEEE 754R Decimal64 format, 16 digits, and a
1.96 + * rounding mode of {@link RoundingMode#HALF_EVEN HALF_EVEN}, the
1.97 + * IEEE 754R default.
1.98 + */
1.99 + public static final MathContext DECIMAL64 =
1.100 + new MathContext(16, RoundingMode.HALF_EVEN);
1.101 +
1.102 + /**
1.103 + * A {@code MathContext} object with a precision setting
1.104 + * matching the IEEE 754R Decimal128 format, 34 digits, and a
1.105 + * rounding mode of {@link RoundingMode#HALF_EVEN HALF_EVEN}, the
1.106 + * IEEE 754R default.
1.107 + */
1.108 + public static final MathContext DECIMAL128 =
1.109 + new MathContext(34, RoundingMode.HALF_EVEN);
1.110 +
1.111 + /* ----- Shared Properties ----- */
1.112 + /**
1.113 + * The number of digits to be used for an operation. A value of 0
1.114 + * indicates that unlimited precision (as many digits as are
1.115 + * required) will be used. Note that leading zeros (in the
1.116 + * coefficient of a number) are never significant.
1.117 + *
1.118 + * <p>{@code precision} will always be non-negative.
1.119 + *
1.120 + * @serial
1.121 + */
1.122 + final int precision;
1.123 +
1.124 + /**
1.125 + * The rounding algorithm to be used for an operation.
1.126 + *
1.127 + * @see RoundingMode
1.128 + * @serial
1.129 + */
1.130 + final RoundingMode roundingMode;
1.131 +
1.132 + /* ----- Constructors ----- */
1.133 +
1.134 + /**
1.135 + * Constructs a new {@code MathContext} with the specified
1.136 + * precision and the {@link RoundingMode#HALF_UP HALF_UP} rounding
1.137 + * mode.
1.138 + *
1.139 + * @param setPrecision The non-negative {@code int} precision setting.
1.140 + * @throws IllegalArgumentException if the {@code setPrecision} parameter is less
1.141 + * than zero.
1.142 + */
1.143 + public MathContext(int setPrecision) {
1.144 + this(setPrecision, DEFAULT_ROUNDINGMODE);
1.145 + return;
1.146 + }
1.147 +
1.148 + /**
1.149 + * Constructs a new {@code MathContext} with a specified
1.150 + * precision and rounding mode.
1.151 + *
1.152 + * @param setPrecision The non-negative {@code int} precision setting.
1.153 + * @param setRoundingMode The rounding mode to use.
1.154 + * @throws IllegalArgumentException if the {@code setPrecision} parameter is less
1.155 + * than zero.
1.156 + * @throws NullPointerException if the rounding mode argument is {@code null}
1.157 + */
1.158 + public MathContext(int setPrecision,
1.159 + RoundingMode setRoundingMode) {
1.160 + if (setPrecision < MIN_DIGITS)
1.161 + throw new IllegalArgumentException("Digits < 0");
1.162 + if (setRoundingMode == null)
1.163 + throw new NullPointerException("null RoundingMode");
1.164 +
1.165 + precision = setPrecision;
1.166 + roundingMode = setRoundingMode;
1.167 + return;
1.168 + }
1.169 +
1.170 + /**
1.171 + * Constructs a new {@code MathContext} from a string.
1.172 + *
1.173 + * The string must be in the same format as that produced by the
1.174 + * {@link #toString} method.
1.175 + *
1.176 + * <p>An {@code IllegalArgumentException} is thrown if the precision
1.177 + * section of the string is out of range ({@code < 0}) or the string is
1.178 + * not in the format created by the {@link #toString} method.
1.179 + *
1.180 + * @param val The string to be parsed
1.181 + * @throws IllegalArgumentException if the precision section is out of range
1.182 + * or of incorrect format
1.183 + * @throws NullPointerException if the argument is {@code null}
1.184 + */
1.185 + public MathContext(String val) {
1.186 + boolean bad = false;
1.187 + int setPrecision;
1.188 + if (val == null)
1.189 + throw new NullPointerException("null String");
1.190 + try { // any error here is a string format problem
1.191 + if (!val.startsWith("precision=")) throw new RuntimeException();
1.192 + int fence = val.indexOf(' '); // could be -1
1.193 + int off = 10; // where value starts
1.194 + setPrecision = Integer.parseInt(val.substring(10, fence));
1.195 +
1.196 + if (!val.startsWith("roundingMode=", fence+1))
1.197 + throw new RuntimeException();
1.198 + off = fence + 1 + 13;
1.199 + String str = val.substring(off, val.length());
1.200 + roundingMode = RoundingMode.valueOf(str);
1.201 + } catch (RuntimeException re) {
1.202 + throw new IllegalArgumentException("bad string format");
1.203 + }
1.204 +
1.205 + if (setPrecision < MIN_DIGITS)
1.206 + throw new IllegalArgumentException("Digits < 0");
1.207 + // the other parameters cannot be invalid if we got here
1.208 + precision = setPrecision;
1.209 + }
1.210 +
1.211 + /**
1.212 + * Returns the {@code precision} setting.
1.213 + * This value is always non-negative.
1.214 + *
1.215 + * @return an {@code int} which is the value of the {@code precision}
1.216 + * setting
1.217 + */
1.218 + public int getPrecision() {
1.219 + return precision;
1.220 + }
1.221 +
1.222 + /**
1.223 + * Returns the roundingMode setting.
1.224 + * This will be one of
1.225 + * {@link RoundingMode#CEILING},
1.226 + * {@link RoundingMode#DOWN},
1.227 + * {@link RoundingMode#FLOOR},
1.228 + * {@link RoundingMode#HALF_DOWN},
1.229 + * {@link RoundingMode#HALF_EVEN},
1.230 + * {@link RoundingMode#HALF_UP},
1.231 + * {@link RoundingMode#UNNECESSARY}, or
1.232 + * {@link RoundingMode#UP}.
1.233 + *
1.234 + * @return a {@code RoundingMode} object which is the value of the
1.235 + * {@code roundingMode} setting
1.236 + */
1.237 +
1.238 + public RoundingMode getRoundingMode() {
1.239 + return roundingMode;
1.240 + }
1.241 +
1.242 + /**
1.243 + * Compares this {@code MathContext} with the specified
1.244 + * {@code Object} for equality.
1.245 + *
1.246 + * @param x {@code Object} to which this {@code MathContext} is to
1.247 + * be compared.
1.248 + * @return {@code true} if and only if the specified {@code Object} is
1.249 + * a {@code MathContext} object which has exactly the same
1.250 + * settings as this object
1.251 + */
1.252 + public boolean equals(Object x){
1.253 + MathContext mc;
1.254 + if (!(x instanceof MathContext))
1.255 + return false;
1.256 + mc = (MathContext) x;
1.257 + return mc.precision == this.precision
1.258 + && mc.roundingMode == this.roundingMode; // no need for .equals()
1.259 + }
1.260 +
1.261 + /**
1.262 + * Returns the hash code for this {@code MathContext}.
1.263 + *
1.264 + * @return hash code for this {@code MathContext}
1.265 + */
1.266 + public int hashCode() {
1.267 + return this.precision + roundingMode.hashCode() * 59;
1.268 + }
1.269 +
1.270 + /**
1.271 + * Returns the string representation of this {@code MathContext}.
1.272 + * The {@code String} returned represents the settings of the
1.273 + * {@code MathContext} object as two space-delimited words
1.274 + * (separated by a single space character, <tt>'\u0020'</tt>,
1.275 + * and with no leading or trailing white space), as follows:
1.276 + * <ol>
1.277 + * <li>
1.278 + * The string {@code "precision="}, immediately followed
1.279 + * by the value of the precision setting as a numeric string as if
1.280 + * generated by the {@link Integer#toString(int) Integer.toString}
1.281 + * method.
1.282 + *
1.283 + * <li>
1.284 + * The string {@code "roundingMode="}, immediately
1.285 + * followed by the value of the {@code roundingMode} setting as a
1.286 + * word. This word will be the same as the name of the
1.287 + * corresponding public constant in the {@link RoundingMode}
1.288 + * enum.
1.289 + * </ol>
1.290 + * <p>
1.291 + * For example:
1.292 + * <pre>
1.293 + * precision=9 roundingMode=HALF_UP
1.294 + * </pre>
1.295 + *
1.296 + * Additional words may be appended to the result of
1.297 + * {@code toString} in the future if more properties are added to
1.298 + * this class.
1.299 + *
1.300 + * @return a {@code String} representing the context settings
1.301 + */
1.302 + public java.lang.String toString() {
1.303 + return "precision=" + precision + " " +
1.304 + "roundingMode=" + roundingMode.toString();
1.305 + }
1.306 +
1.307 + // Private methods
1.308 +
1.309 + /**
1.310 + * Reconstitute the {@code MathContext} instance from a stream (that is,
1.311 + * deserialize it).
1.312 + *
1.313 + * @param s the stream being read.
1.314 + */
1.315 + private void readObject(java.io.ObjectInputStream s)
1.316 + throws java.io.IOException, ClassNotFoundException {
1.317 + s.defaultReadObject(); // read in all fields
1.318 + // validate possibly bad fields
1.319 + if (precision < MIN_DIGITS) {
1.320 + String message = "MathContext: invalid digits in stream";
1.321 + throw new java.io.StreamCorruptedException(message);
1.322 + }
1.323 + if (roundingMode == null) {
1.324 + String message = "MathContext: null roundingMode in stream";
1.325 + throw new java.io.StreamCorruptedException(message);
1.326 + }
1.327 + }
1.328 +
1.329 +}