jsonvalues.JsBool Maven / Gradle / Ivy

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package jsonvalues;


import java.util.Optional;

/**
 Represents an immutable json boolean. Only two instances are created: {@link #FALSE} and {@link #TRUE}
 */
public final class JsBool implements JsValue {
    public static final int ID = 0;
    /**
     The singleton false value.
     */
    public static final JsBool FALSE = new JsBool(false);
    /**
     The singleton true value.
     */
    public static final JsBool TRUE = new JsBool(true);
    /**
     prism between the sum type JsValue and JsBool
     */
    public static Prism prism =
            new Prism<>(s -> s.isBool() ? Optional.of(s.toJsBool().value) : Optional.empty(),
                        JsBool::of
            );
    /**
     the boolean value.
     */
    public final boolean value;


    private JsBool(final boolean value) {
        this.value = value;
    }

    /**
     Static factory method to create a JsBool from a boolean primitive type.

     @param b the boolean value
     @return either {@link JsBool#TRUE} or {@link JsBool#FALSE}
     */
    public static JsBool of(boolean b) {
        return b ? TRUE : FALSE;
    }

    @Override
    public int id() {
        return ID;
    }

    @Override
    public boolean isBool() {
        return true;
    }

    @Override
    public boolean isTrue() {
        return value;
    }

    @Override
    public boolean isFalse() {
        return !value;
    }

    /**
     Returns the hashcode of this json boolean.

     @return 1 if true, 0 if false
     */
    @Override
    public int hashCode() {
        return value ? 1 : 0;
    }

    /**
     Indicates whether some other object is "equal to" this json boolean.

     @param that the reference object with which to compare.
     @return true if that is a JsBool with the same value as this JsBool
     */
    @Override
    public boolean equals(final Object that) {
        if (this == that) return true;
        if (that == null || getClass() != that.getClass()) return false;
        final JsBool thatBool = (JsBool) that;
        return value == thatBool.value;
    }

    /**
     @return "true" or "false"
     */
    @Override
    public String toString() {
        return String.valueOf(value);
    }


}