edu.utah.further.core.api.discrete.EnumUtil.java Source code

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Here is the source code for edu.utah.further.core.api.discrete.EnumUtil.java

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/**
 * Copyright (C) [2013] [The FURTHeR Project]
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package edu.utah.further.core.api.discrete;

import static edu.utah.further.core.api.constant.Strings.ENUM_NAME_SEPARATOR;
import static edu.utah.further.core.api.constant.Strings.SPACE_STRING;
import static edu.utah.further.core.api.lang.CoreUtil.preventUtilityConstruction;
import static org.apache.commons.lang.StringUtils.capitalize;
import static org.apache.commons.lang.StringUtils.lowerCase;
import static org.apache.commons.lang.StringUtils.replaceChars;
import edu.utah.further.core.api.context.Api;
import edu.utah.further.core.api.context.Utility;
import edu.utah.further.core.api.lang.ReflectionUtil;

/**
 * Utilities related to enumerated types and in particular to type conversions.
 * <p>
 * -----------------------------------------------------------------------------------<br>
 * (c) 2008-2013 FURTHeR Project, AVP Health Sciences IT Office, University of Utah<br>
 * Contact: {@code <further@utah.edu>}<br>
 * Biomedical Informatics, 26 South 2000 East<br>
 * Room 5775 HSEB, Salt Lake City, UT 84112<br>
 * Day Phone: 1-801-581-4080<br>
 * -----------------------------------------------------------------------------------
 *
 * @author Oren E. Livne {@code <oren.livne@utah.edu>}
 * @version Oct 13, 2008
 */
@Utility
@Api
public final class EnumUtil {
    // ========================= CONSTANTS =================================

    // ========================= CONSTRUCTORS ==============================

    /**
     * <p>
     * Hide constructor in utility class.
     * </p>
     */
    private EnumUtil() {
        preventUtilityConstruction();
    }

    // ========================= METHODS ===================================

    /**
     * Returns the enum constant of the specified enum type with the specified name. The
     * name must match exactly an identifier used to declare an enum constant in this
     * type. If it does not, this method returns <code>null</code>.
     *
     * @param enumType
     *            the Class object of the enum type from which to return a constant
     * @param name
     *            the name of the constant to return
     * @return the enum constant of the specified enum type with the specified name or
     *         <code>null</code> if not found
     * @see {link Enum.valueOf}
     */
    public static <E extends Enum<E>> E valueOfNullSafe(final Class<E> enumType, final String name) {
        try {
            return Enum.valueOf(enumType, name);
        } catch (final IllegalArgumentException e) {
            return null;
        } catch (final NullPointerException e) {
            return null;
        }
    }

    /**
     * Returns the enum constant of the specified enum type with the specified name. The
     * name must match exactly an identifier used to declare an enum constant in this
     * type. If it does not, this method returns <code>null</code>.
     *
     * @param enumType
     *            the Class object of the enum type from which to return a constant
     * @param name
     *            the name of the constant to return
     * @return the enum constant of the specified enum type with the specified name or
     *         <code>null</code> if not found
     * @see {link Enum.valueOf}
     */
    public static <E extends Enum<E>> E valueOfNullSafe(final Class<E> enumType, final Object object) {
        return (object == null) ? null : valueOfNullSafe(enumType, object.toString());
    }

    /**
     * Create an enumerated type from string representation (factory method).
     *
     * @param enumType
     *            the Class object of the enum type from which to return a constant
     * @param s
     *            string to match
     * @return enum constant whose <code>toString()</code> matches s
     * @see {link Enum.valueOf}
     */
    public static <E extends Enum<E>> E createFromString(final Class<E> enumType, final String s) {
        if (s == null) {
            return null;
        }
        for (final E t : enumType.getEnumConstants()) {
            if (s.equals(t.toString())) {
                return t;
            }
        }
        return null;
    }

    /**
     * Convert a string to an enum. Encapsulates unchecked warning suppression.
     *
     * @param enumType
     * @param value
     * @return
     */
    @SuppressWarnings({ "unchecked", "rawtypes" })
    public static Enum<?> valueOf(final Class<?> enumType, final String value) {
        return Enum.valueOf((Class<Enum>) enumType, value);
    }

    /**
     * Return a default title case string of an enumerated type. The constant's name is
     * converted to lower case, except the first character, which is capitalized.
     * Underscore symbols are replaced by white spaces, for improved readability.
     *
     * @param enumVal
     *            The enumerated value to translate
     *
     * @return a default title case string
     */
    public static String getDisplayString(final Enum<?> enumVal) {
        return capitalize(replaceChars(lowerCase(enumVal.name()), ENUM_NAME_SEPARATOR, SPACE_STRING));
    }

    /**
     * Indicates whether an object is an enum type or not. Uses
     * {@link Enum#isAssignableFrom}, which seems to be safer than {@link Object#isEnum}.
     *
     * @param object
     *            An object
     *
     * @return is the object of enum type
     */
    public static boolean isEnum(final Object object) {
        return ReflectionUtil.instanceOf(object, Enum.class);
    }

    // ========================= PRIVATE METHODS ===========================
}