StringValuedEnumReflect.java

/**
 * Utility class designed to inspect StringValuedEnums.
 *
 * @author wallacew
 */

package com.github.wwadge.hbnpojogen.persistence.impl;


public class StringValuedEnumReflect {

    /**
     * Don't let anyone instantiate this class.
     * @throws UnsupportedOperationException Always.
     */
    private StringValuedEnumReflect() {
        throw new UnsupportedOperationException("This class must not be instantiated.");
    }

    /**
     * All Enum constants (instances) declared in the specified class. 
     * @param enumClass Class to reflect
     * @param <T> Type
     * @return Array of all declared EnumConstants (instances).
     */
    @SuppressWarnings("unchecked")
    private static <T extends Enum> T[]
    getValues(Class<T> enumClass) {
        return enumClass.getEnumConstants();
    }

    /**
     * All possible string values of the string valued enum.
     * @param enumClass Class to reflect.
     * @param <T> Type
     * @return Available string values.
     */
    @SuppressWarnings("unchecked")
    public static <T extends Enum & StringValuedEnum> String[]
    getStringValues(Class<T> enumClass) {
        T[] values = getValues(enumClass);
        String[] result = new String[values.length];
        for (int i = 0; i < values.length; i++) {
            result[i] = values[i].getValue();
        }
        return result;
    }

    /**
     * Name of the enum instance which hold the especified string value.
     * If value has duplicate enum instances than returns the first occurency.
     * @param enumClass Class to inspect.
     * @param value String.
     * @param <T> Type
     * @return name of the enum instance.
     */
    @SuppressWarnings("unchecked")
    public static <T extends Enum & StringValuedEnum> String
    getNameFromValue(Class<T> enumClass, Object value) {
        T[] values = getValues(enumClass);
        for (int i = 0; i < values.length; i++) {
            if (values[i].getValue().toString().equals(value.toString())) {
                return values[i].name();
            }
        }
        return "";
    }

}