source: issuevalue/src/main/java/geniusweb/issuevalue/DiscreteValue.java

package geniusweb.issuevalue;

import com.fasterxml.jackson.annotation.JsonValue;

/**
 * A value for a discrete issue. Constructor guarantees this is non-null and
 * non-empty. immutable.
 */
public class DiscreteValue implements Value {

        @JsonValue // serializes nicely but requires custom deserializer.
        private final String value;

        public DiscreteValue(String value) {
                if (value == null || value.isEmpty())
                        throw new NullPointerException(
                                        "value must be non-null and non-empty");
                this.value = value;
        }

        @Override
        public int hashCode() {
                final int prime = 31;
                int result = 1;
                result = prime * result + ((value == null) ? 0 : value.hashCode());
                return result;
        }

        @Override
        public boolean equals(Object obj) {
                if (this == obj)
                        return true;
                if (obj == null)
                        return false;
                if (getClass() != obj.getClass())
                        return false;
                DiscreteValue other = (DiscreteValue) obj;
                if (value == null) {
                        if (other.value != null)
                                return false;
                } else if (!value.equals(other.value))
                        return false;
                return true;
        }

        @Override
        public String toString() {
                return "\"" + value + "\"";
        }

        public String getValue() {
                return value;
        }
}