com.feilong.core.lang.EnumUtil Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of feilong Show documentation
Show all versions of feilong Show documentation
feilong is a suite of core and expanded libraries that include utility classes, http, excel,cvs, io classes, and much much more.
/*
* Copyright (C) 2008 feilong
*
* 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 com.feilong.core.lang;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.feilong.core.bean.BeanOperationException;
import com.feilong.core.bean.PropertyUtil;
import com.feilong.lib.lang3.StringUtils;
import com.feilong.core.Validate;
import com.feilong.tools.slf4j.Slf4jUtil;
/**
* {@link java.lang.Enum} 工具类.
*
* @author feilong
* @see com.feilong.lib.lang3.EnumUtils
* @since 1.0.6
*/
public final class EnumUtil{
/** The Constant LOGGER. */
private static final Logger LOGGER = LoggerFactory.getLogger(EnumUtil.class);
/** Don't let anyone instantiate this class. */
private EnumUtil(){
//AssertionError不是必须的. 但它可以避免不小心在类的内部调用构造器. 保证该类在任何情况下都不会被实例化.
//see 《Effective Java》 2nd
throw new AssertionError("No " + getClass().getName() + " instances for you!");
}
//---------------------------------------------------------------
/**
* 通过propertyName的 specifiedValue(忽视大小写) 获得枚举(equalsIgnoreCase判断).
*
* 说明:
*
*
*
* -
*
*
* 适用于这种 HttpMethodType 带自定义属性的枚举类型,
*
*
*
* public enum HttpMethodType{
*
* GET("get"),
*
* POST("post");
*
* private String method;
*
* private HttpMethodType(String method){
* this.method = method;
* }
*
* public String getMethod(){
* return method;
* }
* }
*
*
*
* 要取HttpMethodType 里面的 method属性值是 "get"的枚举(忽视大小写),调用方式:
*
*
*
* EnumUtil.getEnumByPropertyValueIgnoreCase(HttpMethodType.class, "method", "get")
*
*
*
*
* - 如果你需要值区分大小写,可以调用 {@link #getEnumByPropertyValue(Class, String, Object)}
*
*
*
* @param
* the element type
* @param
* the generic type
* @param enumClass
* 枚举类 比如 HttpMethodType
* @param propertyName
* 字段名称,比如 HttpMethodType 的method,按照javabean 规范
* @param specifiedValue
* 属性值 比如post
* @return 如果遍历所有枚举值,找不到枚举值的属性propertyName的值是 specifiedValue,那么返回null
* @throws NullPointerException
* 如果 enumClass 是null,或者 propertyName 是null
* @throws IllegalArgumentException
* 如果 propertyName 是blank
* @throws BeanOperationException
* 如果枚举值没有相关 propertyName 属性,比如 HttpMethodType 有 "method" 属性,但是没有 "method2222" 属性
* @see #getEnumByPropertyValue(Class, String, Object, boolean)
*/
public static , T> E getEnumByPropertyValueIgnoreCase(Class enumClass,String propertyName,T specifiedValue){
return getEnumByPropertyValue(enumClass, propertyName, specifiedValue, true);
}
/**
* 通过propertyName的 specifiedValue 获得枚举(equals判断,区分大小写).
*
* 说明:
*
*
*
* -
*
*
* 适用于这种 HttpMethodType 带自定义属性的枚举类型,
*
*
*
* public enum HttpMethodType{
*
* GET("get"),
*
* POST("post");
*
* private String method;
*
* private HttpMethodType(String method){
* this.method = method;
* }
*
* public String getMethod(){
* return method;
* }
*
* }
*
*
*
* 要取HttpMethodType 里面的 method属性值是 "get"的枚举(区分大小写),调用方式:
*
*
*
* EnumUtil.getEnumByPropertyValue(HttpMethodType.class, "method", "get")
*
*
*
*
* - 如果你需要值不区分大小写,可以调用 {@link #getEnumByPropertyValueIgnoreCase(Class, String, Object)}
*
*
*
* @param
* the element type
* @param
* the generic type
* @param enumClass
* 枚举类 比如 HttpMethodType
* @param propertyName
* 字段名称,比如 HttpMethodType 的method,按照javabean 规范
* @param specifiedValue
* 属性值 比如post
* @return 如果遍历所有枚举值,找不到枚举值的属性propertyName的值是 specifiedValue,那么返回null
* @throws NullPointerException
* 如果 enumClass 是null,或者 propertyName 是null
* @throws IllegalArgumentException
* 如果 propertyName 是blank
* @throws BeanOperationException
* 如果枚举值没有相关 propertyName 属性,比如 HttpMethodType 有 "method" 属性,但是没有 "method2222" 属性
* @since 1.0.8
*/
public static , T> E getEnumByPropertyValue(Class enumClass,String propertyName,T specifiedValue){
return getEnumByPropertyValue(enumClass, propertyName, specifiedValue, false);
}
//---------------------------------------------------------------
/**
* 通过propertyName的 specifiedValue 获得枚举.
*
* @param
* the element type
* @param
* the generic type
* @param enumClass
* 枚举类 比如 HttpMethodType
* @param propertyName
* 字段名称,比如 HttpMethodType 的method,按照javabean 规范
* @param specifiedValue
* 属性值 比如post
* @param ignoreCase
* 是否忽视大小写
* @return the enum by property value
* @throws NullPointerException
* 如果 enumClass 是null,或者 propertyName 是null
* @throws IllegalArgumentException
* 如果 propertyName 是blank
* @throws BeanOperationException
* 如果枚举值没有相关 propertyName 属性,比如 HttpMethodType 有 "method" 属性,但是没有 "method2222" 属性
* @see com.feilong.core.bean.PropertyUtil#getProperty(Object, String)
* @since 1.0.8
*/
private static , T> E getEnumByPropertyValue(
Class enumClass,
String propertyName,
T specifiedValue,
boolean ignoreCase){
Validate.notNull(enumClass, "enumClass can't be null!");
Validate.notBlank(propertyName, "propertyName can't be null/empty!");
//---------------------------------------------------------------
// An enum is a kind of class
// An annotation is a kind of interface
// 如果Class 对象不表示枚举类型,则返回枚举类的元素或 null.
E[] enumConstants = enumClass.getEnumConstants();
if (LOGGER.isTraceEnabled()){
LOGGER.trace("enumClass:[{}],enumConstants:[{}]", enumClass.getCanonicalName(), enumConstants);
}
//---------------------------------------------------------------
for (E e : enumConstants){
Object propertyValue = PropertyUtil.getProperty(e, propertyName);
if (isEquals(propertyValue, specifiedValue, ignoreCase)){
return e;
}
}
//---------------------------------------------------------------
if (LOGGER.isDebugEnabled()){
String messagePattern = "[{}],propertyName:[{}],value:[{}],ignoreCase:[{}],constants not found";
LOGGER.debug(Slf4jUtil.format(messagePattern, enumClass, propertyName, specifiedValue, ignoreCase));
}
return null;
}
/**
* Checks if is equals.
*
* @param
* the generic type
* @param propertyValue
* the property value
* @param specifiedValue
* 指定的值
* @param ignoreCase
* the ignore case
* @return true, if checked
* @since 1.4.0
*/
private static boolean isEquals(Object propertyValue,T specifiedValue,boolean ignoreCase){
if (propertyValue == null || specifiedValue == null){//很好的设计 赞一个
return propertyValue == specifiedValue;
}else if (propertyValue == specifiedValue){
return true;
}
//---------------------------------------------------------------
//到这里 propertyValue 和 specifiedValue, 肯定 不是null了
String propertyValueString = propertyValue.toString();
String specifiedValueString = specifiedValue.toString();
return ignoreCase ? StringUtils.equalsIgnoreCase(propertyValueString, specifiedValueString)
: StringUtils.equals(propertyValueString, specifiedValueString);
}
}