1 | package geniusweb.bidspace;
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2 |
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3 | import java.math.BigDecimal;
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4 | import java.math.RoundingMode;
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5 |
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6 | import org.eclipse.jdt.annotation.NonNull;
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7 |
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8 | /**
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9 | * An interval [min, max].
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10 | *
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11 | */
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12 | public class Interval {
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13 | public static @NonNull Interval ZERO = new Interval(BigDecimal.ZERO,
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14 | BigDecimal.ZERO);
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15 | public static @NonNull Interval EMPTY = new Interval(BigDecimal.ONE,
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16 | BigDecimal.ZERO);
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17 |
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18 | private final @NonNull BigDecimal min;
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19 | private final @NonNull BigDecimal max;
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20 |
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21 | /**
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22 | * AN interval [min,max]. If min > max, then there are no values in this
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23 | * interval.
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24 | *
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25 | * @param min the minimum value of the interval (inclusive)
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26 | * @param max the maximum value of the interval (inclusive)
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27 | */
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28 | public Interval(@NonNull BigDecimal min, @NonNull BigDecimal max) {
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29 | if (min == null || max == null) {
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30 | throw new NullPointerException("min and max must contain not null");
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31 | }
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32 | this.min = min;
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33 | this.max = max;
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34 | }
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35 |
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36 | @NonNull
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37 | /**
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38 | *
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39 | * @return the minimum value of the interval
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40 | */
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41 | public BigDecimal getMin() {
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42 | return min;
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43 | }
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44 |
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45 | @NonNull
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46 | /**
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47 | *
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48 | * @return the maximum value of the interval
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49 | */
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50 | public BigDecimal getMax() {
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51 | return max;
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52 | }
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53 |
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54 | /**
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55 | *
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56 | * @return true iff this range does not contain any element.
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57 | */
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58 | public boolean isEmpty() {
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59 | return min.compareTo(max) > 0;
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60 | }
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61 |
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62 | /**
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63 | *
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64 | * @param value the value to test
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65 | * @return true iff min ≤ value ≤ max
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66 | */
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67 | public boolean contains(@NonNull BigDecimal value) {
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68 | return min.compareTo(value) <= 0 && max.compareTo(value) >= 0;
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69 | }
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70 |
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71 | @NonNull
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72 | /**
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73 | *
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74 | * @param other {@link Interval} to be added to this
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75 | * @return new interval [ this.min + other.min , this.max + other.max ]
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76 | */
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77 | public Interval add(@NonNull Interval other) {
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78 | return new Interval(min.add(other.min), max.add(other.max));
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79 | }
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80 |
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81 | @NonNull
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82 | /**
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83 | *
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84 | * @param other another {@link Interval} intersect with
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85 | * @return intersection of this with other. returns null if intersection is
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86 | * empty.
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87 | */
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88 | public Interval intersect(@NonNull Interval other) {
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89 | return new Interval(min.max(other.min), max.min(other.max));
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90 | }
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91 |
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92 | @NonNull
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93 | /**
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94 | *
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95 | * @param other the other minmax to deal with
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96 | * @return the range of values that, when added to a value from other, will
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97 | * possibly get in our range. effectively, [min-other.max,
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98 | * max-other.min]. Returns {@link #EMPTY} if the resulting range is
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99 | * empty.
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100 | */
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101 | public Interval invert(@NonNull Interval other) {
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102 | final @NonNull BigDecimal newmin = min.subtract(other.max);
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103 | final @NonNull BigDecimal newmax = max.subtract(other.min);
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104 | if (newmin.compareTo(newmax) > 0)
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105 | return EMPTY;
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106 | return new Interval(newmin, newmax);
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107 | }
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108 |
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109 | @NonNull
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110 | /**
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111 | *
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112 | * @param value the value to subtract
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113 | * @return Interval with both min and max reduced by value.
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114 | */
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115 | public Interval subtract(@NonNull BigDecimal value) {
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116 | return new Interval(min.subtract(value), max.subtract(value));
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117 | }
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118 |
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119 | public @NonNull Interval multiply(@NonNull BigDecimal weight) {
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120 | return new Interval(min.multiply(weight), max.multiply(weight));
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121 | }
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122 |
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123 | @Override
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124 | public @NonNull String toString() {
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125 | return "Interval[" + min + "," + max + "]";
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126 | }
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127 |
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128 | @NonNull
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129 | /**
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130 | * @param precision number of digits required
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131 | * @return this but with modified precision. The interval is rounded so that
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132 | * the new interval is inside the old one.
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133 | */
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134 | public Interval round(int precision) {
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135 | return new Interval(min.setScale(precision, RoundingMode.UP),
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136 | max.setScale(precision, RoundingMode.DOWN));
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137 | }
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138 |
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139 | @Override
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140 | public int hashCode() {
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141 | final int prime = 31;
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142 | int result = 1;
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143 | result = prime * result + ((max == null) ? 0 : max.hashCode());
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144 | result = prime * result + ((min == null) ? 0 : min.hashCode());
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145 | return result;
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146 | }
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147 |
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148 | @Override
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149 | public boolean equals(Object obj) {
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150 | if (this == obj)
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151 | return true;
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152 | if (obj == null)
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153 | return false;
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154 | if (getClass() != obj.getClass())
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155 | return false;
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156 | Interval other = (Interval) obj;
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157 | if (max == null) {
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158 | if (other.max != null)
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159 | return false;
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160 |
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161 | } else if (max.compareTo(other.max) != 0)
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162 | // THIS WAS FIXED MANUALLY TO USE COMPARETO
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163 | return false;
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164 | if (min == null) {
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165 | if (other.min != null)
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166 | return false;
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167 | } else if (min.compareTo(other.min) != 0)
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168 | // THIS WAS FIXED MANUALLY TO USE COMPARETO
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169 | return false;
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170 | return true;
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171 | }
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172 |
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173 | }
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