Java tutorial
/** * Copyright 2014 Andreas Schildbach * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.matthewmitchell.nubitsj.core; import com.matthewmitchell.nubitsj.utils.MonetaryFormat; import com.google.common.math.LongMath; import java.io.Serializable; import java.math.BigDecimal; import static com.google.common.base.Preconditions.checkArgument; /** * Represents a monetary Bitcoin value. This class is immutable. */ public final class Coin implements Monetary, Comparable<Coin>, Serializable { /** * Number of decimals for one Nubits. This constant is useful for quick adapting to other coins because a lot of * constants derive from it. */ public static final int SMALLEST_UNIT_EXPONENT = 4; /** * The number of satoshis equal to one nubits. */ private static final long COIN_VALUE = LongMath.pow(10, SMALLEST_UNIT_EXPONENT); /** * Zero Nubitss. */ public static final Coin ZERO = Coin.valueOf(0); /** * One Nubits. */ public static final Coin COIN = Coin.valueOf(COIN_VALUE); /** * 0.01 Nubitss. This unit is not really used much. */ public static final Coin CENT = COIN.divide(100); /** * 0.001 Nubitss, also known as 1 mNBT. */ public static final Coin MILLICOIN = COIN.divide(1000); /** * 0.000001 Nubits, also known as 1 NBT or 1 uNBT. */ public static final Coin MICROCOIN = MILLICOIN.divide(1000); /** * A satoshi is the smallest unit that can be transferred. 1 million of them fit into a Nubits. */ public static final Coin SATOSHI = Coin.valueOf(1); /** * Represents a monetary value of minus one satoshi. */ public static final Coin NEGATIVE_SATOSHI = Coin.valueOf(-1); /** * The number of satoshis of this monetary value. */ public final long value; private final long MAX_SATOSHIS = COIN_VALUE * NetworkParameters.MAX_COINS; private Coin(final long satoshis) { checkArgument(-MAX_SATOSHIS <= satoshis && satoshis <= MAX_SATOSHIS, "%s satoshis exceeds maximum possible quantity of Nubits.", satoshis); this.value = satoshis; } public static Coin valueOf(final long satoshis) { return new Coin(satoshis); } @Override public int smallestUnitExponent() { return SMALLEST_UNIT_EXPONENT; } /** * Returns the number of satoshis of this monetary value. */ @Override public long getValue() { return value; } /** * Convert an amount expressed in the way humans are used to into satoshis. */ public static Coin valueOf(final int coins, final int cents) { checkArgument(cents < 100); checkArgument(cents >= 0); checkArgument(coins >= 0); final Coin coin = COIN.multiply(coins).add(CENT.multiply(cents)); checkArgument(coin.compareTo(NetworkParameters.MAX_MONEY) <= 0); return coin; } /** * Parses an amount expressed in the way humans are used to.<p> * <p/> * This takes string in a format understood by {@link BigDecimal#BigDecimal(String)}, * for example "0", "1", "0.10", "1.23E3", "1234.5E-5". * * @throws IllegalArgumentException if you try to specify fractional satoshis, or a value out of range. */ public static Coin parseCoin(final String str) { return Coin.valueOf( new BigDecimal(str).movePointRight(SMALLEST_UNIT_EXPONENT).toBigIntegerExact().longValue()); } public Coin add(final Coin value) { return new Coin(LongMath.checkedAdd(this.value, value.value)); } public Coin subtract(final Coin value) { return new Coin(LongMath.checkedSubtract(this.value, value.value)); } public Coin multiply(final long factor) { return new Coin(LongMath.checkedMultiply(this.value, factor)); } public Coin divide(final long divisor) { return new Coin(this.value / divisor); } public Coin[] divideAndRemainder(final long divisor) { return new Coin[] { new Coin(this.value / divisor), new Coin(this.value % divisor) }; } public long divide(final Coin divisor) { return this.value / divisor.value; } /** * Returns true if and only if this instance represents a monetary value greater than zero, * otherwise false. */ public boolean isPositive() { return signum() == 1; } /** * Returns true if and only if this instance represents a monetary value less than zero, * otherwise false. */ public boolean isNegative() { return signum() == -1; } /** * Returns true if and only if this instance represents zero monetary value, * otherwise false. */ public boolean isZero() { return signum() == 0; } /** * Returns true if the monetary value represented by this instance is greater than that * of the given other Coin, otherwise false. */ public boolean isGreaterThan(Coin other) { return compareTo(other) > 0; } /** * Returns true if the monetary value represented by this instance is less than that * of the given other Coin, otherwise false. */ public boolean isLessThan(Coin other) { return compareTo(other) < 0; } public Coin shiftLeft(final int n) { return new Coin(this.value << n); } public Coin shiftRight(final int n) { return new Coin(this.value >> n); } @Override public int signum() { if (this.value == 0) return 0; return this.value < 0 ? -1 : 1; } public Coin negate() { return new Coin(-this.value); } /** * Returns the number of satoshis of this monetary value. It's deprecated in favour of accessing {@link #value} * directly. */ public long longValue() { return this.value; } private static final MonetaryFormat FRIENDLY_FORMAT = MonetaryFormat.NBT.minDecimals(2) .repeatOptionalDecimals(1, 2).postfixCode(); /** * Returns the value as a 0.12 type string. More digits after the decimal place will be used * if necessary, but two will always be present. */ public String toFriendlyString() { return FRIENDLY_FORMAT.format(this).toString(); } private static final MonetaryFormat PLAIN_FORMAT = MonetaryFormat.NBT.minDecimals(0) .repeatOptionalDecimals(1, 4).noCode(); /** * <p> * Returns the value as a plain string denominated in NBT. * The result is unformatted with no trailing zeroes. * For instance, a value of 150000 satoshis gives an output string of "0.0015" NBT * </p> */ public String toPlainString() { return PLAIN_FORMAT.format(this).toString(); } @Override public String toString() { return Long.toString(value); } @Override public boolean equals(final Object o) { if (o == this) return true; if (o == null || o.getClass() != getClass()) return false; final Coin other = (Coin) o; if (this.value != other.value) return false; return true; } @Override public int hashCode() { return (int) this.value; } @Override public int compareTo(final Coin other) { if (this.value == other.value) return 0; return this.value > other.value ? 1 : -1; } }