yakworks.commons.lang.EnumUtils Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 yakworks.commons.lang;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
import java.util.stream.Stream;
/**
* Utility library to provide helper methods for Java enums.
*
* #ThreadSafe#
*
* @since 3.0
*/
public class EnumUtils {
private static final String NULL_ELEMENTS_NOT_PERMITTED = "null elements not permitted";
private static final String CANNOT_STORE_S_S_VALUES_IN_S_BITS = "Cannot store %s %s values in %s bits";
private static final String S_DOES_NOT_SEEM_TO_BE_AN_ENUM_TYPE = "%s does not seem to be an Enum type";
private static final String ENUM_CLASS_MUST_BE_DEFINED = "EnumClass must be defined.";
/**
* Validate {@code enumClass}.
* @param the type of the enumeration
* @param enumClass to check
* @return {@code enumClass}
* @throws NullPointerException if {@code enumClass} is {@code null}
* @throws IllegalArgumentException if {@code enumClass} is not an enum class
* @since 3.2
*/
private static > Class asEnum(final Class enumClass) {
Validate.notNull(enumClass, ENUM_CLASS_MUST_BE_DEFINED);
Validate.isTrue(enumClass.isEnum(), S_DOES_NOT_SEEM_TO_BE_AN_ENUM_TYPE, enumClass);
return enumClass;
}
/**
* Gets the enum for the class, returning {@code null} if not found.
*
* This method differs from {@link Enum#valueOf} in that it does not throw an exception
* for an invalid enum name.
*
* @param the type of the enumeration
* @param enumClass the class of the enum to query, not null
* @param enumName the enum name, null returns null
* @return the enum, null if not found
*/
public static > E getEnum(final Class enumClass, final String enumName) {
return getEnum(enumClass, enumName, null);
}
/**
* Gets the enum for the class, returning {@code defaultEnum} if not found.
*
* This method differs from {@link Enum#valueOf} in that it does not throw an exception
* for an invalid enum name.
*
* @param the type of the enumeration
* @param enumClass the class of the enum to query, not null
* @param enumName the enum name, null returns default enum
* @param defaultEnum the default enum
* @return the enum, default enum if not found
* @since 3.10
*/
public static > E getEnum(final Class enumClass, final String enumName, final E defaultEnum) {
if (enumName == null) {
return defaultEnum;
}
try {
return Enum.valueOf(enumClass, enumName);
} catch (final IllegalArgumentException ex) {
return defaultEnum;
}
}
/**
* Gets the enum for the class, returning {@code null} if not found.
*
* This method differs from {@link Enum#valueOf} in that it does not throw an exception
* for an invalid enum name and performs case insensitive matching of the name.
*
* @param the type of the enumeration
* @param enumClass the class of the enum to query, not null
* @param enumName the enum name, null returns null
* @return the enum, null if not found
* @since 3.8
*/
public static > E getEnumIgnoreCase(final Class enumClass, final String enumName) {
return getEnumIgnoreCase(enumClass, enumName, null);
}
/**
* Gets the enum for the class, returning {@code defaultEnum} if not found.
*
* This method differs from {@link Enum#valueOf} in that it does not throw an exception
* for an invalid enum name and performs case insensitive matching of the name.
*
* @param the type of the enumeration
* @param enumClass the class of the enum to query, not null
* @param enumName the enum name, null returns default enum
* @param defaultEnum the default enum
* @return the enum, default enum if not found
* @since 3.10
*/
public static > E getEnumIgnoreCase(final Class enumClass, final String enumName, final E defaultEnum) {
if (enumName == null || !enumClass.isEnum()) {
return defaultEnum;
}
for (final E each : enumClass.getEnumConstants()) {
if (each.name().equalsIgnoreCase(enumName)) {
return each;
}
}
return defaultEnum;
}
/**
* Gets the {@code List} of enums.
*
* This method is useful when you need a list of enums rather than an array.
*
* @param the type of the enumeration
* @param enumClass the class of the enum to query, not null
* @return the modifiable list of enums, never null
*/
public static > List getEnumList(final Class enumClass) {
return new ArrayList<>(Arrays.asList(enumClass.getEnumConstants()));
}
/**
* Gets the {@code Map} of enums by name.
*
* This method is useful when you need a map of enums by name.
*
* @param the type of the enumeration
* @param enumClass the class of the enum to query, not null
* @return the modifiable map of enum names to enums, never null
*/
public static > Map getEnumMap(final Class enumClass) {
final Map map = new LinkedHashMap<>();
for (final E e: enumClass.getEnumConstants()) {
map.put(e.name(), e);
}
return map;
}
/**
* Checks if the specified name is a valid enum for the class.
*
* This method differs from {@link Enum#valueOf} in that checks if the name is
* a valid enum without needing to catch the exception.
*
* @param the type of the enumeration
* @param enumClass the class of the enum to query, not null
* @param enumName the enum name, null returns false
* @return true if the enum name is valid, otherwise false
*/
public static > boolean isValidEnum(final Class enumClass, final String enumName) {
return getEnum(enumClass, enumName) != null;
}
/**
* Checks if the specified name is a valid enum for the class.
*
* This method differs from {@link Enum#valueOf} in that checks if the name is
* a valid enum without needing to catch the exception
* and performs case insensitive matching of the name.
*
* @param the type of the enumeration
* @param enumClass the class of the enum to query, not null
* @param enumName the enum name, null returns false
* @return true if the enum name is valid, otherwise false
*/
public static > boolean isValidEnumIgnoreCase(final Class enumClass, final String enumName) {
return getEnumIgnoreCase(enumClass, enumName) != null;
}
/**
* This constructor is public to permit tools that require a JavaBean
* instance to operate.
*/
public EnumUtils() {
}
}