001/**
002 * The MIT License (MIT)
003 *
004 * Copyright (c) 2015-2016 decimal4j (tools4j), Marco Terzer
005 *
006 * Permission is hereby granted, free of charge, to any person obtaining a copy
007 * of this software and associated documentation files (the "Software"), to deal
008 * in the Software without restriction, including without limitation the rights
009 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
010 * copies of the Software, and to permit persons to whom the Software is
011 * furnished to do so, subject to the following conditions:
012 *
013 * The above copyright notice and this permission notice shall be included in all
014 * copies or substantial portions of the Software.
015 *
016 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
017 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
018 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
019 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
020 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
021 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
022 * SOFTWARE.
023 */
024package org.decimal4j.exact;
025
026import java.util.Objects;
027
028import org.decimal4j.api.Decimal;
029import org.decimal4j.immutable.Decimal0f;
030import org.decimal4j.immutable.Decimal18f;
031import org.decimal4j.mutable.MutableDecimal0f;
032import org.decimal4j.scale.Scale18f;
033
034/**
035 * A {@code Multipliable18f} encapsulates a Decimal of scale 18 and facilitates
036 * exact typed multiplication. The multipliable object acts as first factor in the multiplication
037 * and provides a set of overloaded methods for different scales. Each one of those methods 
038 * delivers a different result scale which represents the appropriate scale for the product of
039 * an exact multiplication.
040 * <p>
041 * A {@code Multipliable18f} object is returned by {@link Decimal18f#multiplyExact()},
042 * hence an exact typed multiplication can be written as:
043 * <pre>
044 * Decimal18f value = ... //some value
045 * Decimal18f product = value.multiplyExact().by(Decimal0f.FIVE);
046 * </pre>
047 */
048public final class Multipliable18f {
049        
050        private final Decimal<Scale18f> value;
051        
052        /**
053         * Constructor with Decimal value to be encapsulated.
054         * @param value the decimal value to be wrapped as a multipliable object
055         */
056        public Multipliable18f(Decimal<Scale18f> value) {
057                this.value = Objects.requireNonNull(value, "value cannot be null");
058        }
059        
060        /**
061         * Returns the value underlying this Multipliable18f.
062         * @return the Decimal value wrapped by this multipliable object
063         */
064        public Decimal<Scale18f> getValue() {
065                return value;
066        }
067
068        /**
069         * Returns a {@code Decimal} whose value is {@code (this * factor)}. The
070         * result is exact and has scale 18 which is the sum of the scales 
071         * of the Decimal that this multipliable object represents and the scale of
072         * the {@code factor} argument. An {@link ArithmeticException} is thrown if the 
073         * product is out of the possible range for a {@code Decimal18f}.
074         * <p>
075         * Note that the result is <i>always</i> a new instance.
076         * 
077         * @param factor
078         *            the factor to multiply with the Decimal that this multipliable represents
079         * @return <tt>(this * factor)</tt>
080         * @throws ArithmeticException
081         *             if an overflow occurs and product is out of the possible
082         *             range for a {@code Decimal18f}
083         */
084        public Decimal18f by(Decimal0f factor) {
085                return Decimal18f.valueOf(this.value.multiplyExact(factor));
086        }
087        /**
088         * Returns a {@code Decimal} whose value is {@code (this * factor)}. The
089         * result is exact and has scale 18 which is the sum of the scales 
090         * of the Decimal that this multipliable object represents and the scale of
091         * the {@code factor} argument. An {@link ArithmeticException} is thrown if the 
092         * product is out of the possible range for a {@code Decimal18f}.
093         * <p>
094         * Note that the result is <i>always</i> a new instance.
095         * 
096         * @param factor
097         *            the factor to multiply with the Decimal that this multipliable represents
098         * @return <tt>(this * factor)</tt>
099         * @throws ArithmeticException
100         *             if an overflow occurs and product is out of the possible
101         *             range for a {@code Decimal18f}
102         */
103        public Decimal18f by(MutableDecimal0f factor) {
104                return Decimal18f.valueOf(this.value.multiplyExact(factor));
105        }
106
107        
108        /**
109         * Returns a hash code for this <tt>Multipliable18f</tt> which happens to be the 
110         * hash code of the underlying {@code Decimal18f} value.
111         * 
112         * @return a hash code value for this object
113         * @see Decimal#hashCode()
114         */
115        @Override
116        public int hashCode() {
117                return value.hashCode();
118        }
119
120        /**
121         * Compares this Multipliable18f to the specified object. The result is {@code true}
122         * if and only if the argument is a {@code Multipliable18f} with an equal underlying 
123         * {@link #getValue() value}.
124         * 
125         * @param obj
126         *            the object to compare with
127         * @return {@code true} if the argument is a {@code Multipliable18f} and if its value
128         *         is equal to this multipliables's value; {@code false} otherwise
129         * @see #getValue()
130         * @see Decimal#equals(Object)
131         */
132        @Override
133        public boolean equals(Object obj) {
134                if (this == obj) return true;
135                if (obj == null) return false;
136                if (getClass() != obj.getClass()) return false;
137                return value.equals(((Multipliable18f)obj).value);
138        }
139
140        /**
141         * Returns a string representation of this {@code Multipliable18f} which is
142         * simply the string representation of the underlying Decimal {@link #getValue() value}.
143         * 
144         * @return a {@code String} Decimal representation of this {@code Multipliable18f}'s
145         *         value with all the fraction digits (including trailing zeros)
146         * @see #getValue()
147         * @see Decimal#toString()
148         */
149        @Override
150        public String toString() {
151                return value.toString();
152        }
153}