61 lines
1.6 KiB
Java
61 lines
1.6 KiB
Java
package expression.common;
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import base.Either;
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import java.util.function.LongUnaryOperator;
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import java.util.function.Supplier;
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/**
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* @author Georgiy Korneev (kgeorgiy@kgeorgiy.info)
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*/
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public final class Reason {
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public static final Reason OVERFLOW = new Reason("Overflow");
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public static final Reason DBZ = new Reason("Division by zero");
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private final String description;
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public Reason(final String description) {
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this.description = description;
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}
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public static <T> Either<Reason, T> eval(final Supplier<T> action) {
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try {
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return Either.right(action.get());
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} catch (final ReasonException e) {
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return Either.left(e.reason);
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}
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}
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public static int overflow(final long value) {
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return value < Integer.MIN_VALUE || Integer.MAX_VALUE < value
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? OVERFLOW.error()
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: (int) value;
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}
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public <T> T error() {
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throw new ReasonException(this);
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}
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public LongUnaryOperator less(final long limit, final LongUnaryOperator op) {
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return a -> a < limit ? error() : op.applyAsLong(a);
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}
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public LongUnaryOperator greater(final int limit, final LongUnaryOperator op) {
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return a -> a > limit ? error() : op.applyAsLong(a);
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}
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private static class ReasonException extends RuntimeException {
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private final Reason reason;
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public ReasonException(final Reason reason) {
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super(reason.description);
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this.reason = reason;
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}
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}
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@Override
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public String toString() {
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return String.format("Reason(%s)", description);
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}
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}
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