/*
* Copyright (c) 2008-2016 Computer Network Information Center (CNIC), Chinese Academy of Sciences.
*
* This file is part of Duckling 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 cn.vlabs.umt.common.util;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.regex.Pattern;
/**常用的工具类了
* @author lvly
* @since 2012-6-18
* */
public final class CommonUtils {
public static final Pattern INT = Pattern.compile("^\\d+$|-\\d+$");
public static final Pattern DOUBLE = Pattern.compile("\\d+\\.\\d+$|-\\d+\\.\\d+$");
private CommonUtils(){}
/**
* 判断是否为数字，小数或者整数
* */
public static boolean isNumber(String str){
if(isNull(str)){
return false;
}
return INT.matcher(str).find()||DOUBLE.matcher(str).find();
}
/**
* 通用是否为空
* @param obj
* @return isNull or isEmpty
* */
public static boolean isNull(Object obj){
if(obj==null){
return true;
}
if(obj instanceof List){
return isNull((List<?>)obj);
}else if(obj instanceof Map){
return isNull((Map<?,?>)obj);
}else if(obj instanceof String[]){
return isNull((String[])obj);
}else if(obj instanceof int[]){
return isNull((int[])obj);
}else if(obj instanceof Set){
return isNull((Set<?>)obj);
}else if(obj instanceof String){
return isNull((String)obj);
}else if(obj instanceof Object[]){
return isNull((Object[])obj);
}
//最好不要走到这一步
return false;
}
/**判断数组是否为空，判断.split出来的数组格外有效
* @param array 判定数组
* */
public static boolean isNull(String[] array){
return (array==null||array.length==0||(array.length==1&&"".equals(array[0])));
}
public static boolean isNull(Object[] array){
return (array==null||array.length==0);
}
/**判断数组为空，int类型
* @param array int类型的判定数组
* */
public static boolean isNull(int[] array){
return (array==null||array.length==0);
}
/**是否空列表，
* @param list 待判定列表
* */
public static boolean isNull(List<?> list){
return (list==null)||(list.size()==0);
}
/**是否空列表，
* @param list 待判定列表
* */
public static boolean isNull(Set<?> list){
return (list==null)||(list.size()==0);
}
/**
* 判断是否是空集合
* @param map Map对象
* */
public static boolean isNull(Map<?,?> map){
return (map==null||(map.isEmpty()));
}
/**把单个的对象转化为数组，匹配参数用
* @param k 某一个对象
* @return List<K>
* */
public static <K> List<K> getList(K k){
List<K> ks=new ArrayList<K>();
ks.add(k);
return ks;
}
/**把队列里的第一个元素拿出来而不抛异常
* @param List<K> 原队列
* @return K 第一个元素
* */
public static <K> K first(List<K> list){
if(isNull(list)){
return null;
}
return list.get(0);
}
/**判断字符串是否为空
* @param str the String what need to judice
* @param boolean isNull?
* */
public static boolean isNull(String str){
return str==null||"".equals(str.trim())||"null".equals(str.toLowerCase().trim());
}
/**杀掉空串和空
* @param str the String what need to judice
* @param str never return null
* */
public static String killNull(Object obj){
return CommonUtils.isNull(obj)?"":obj.toString().trim();
}
/**
* 同上，不过只是针对字符串
* @param str the String what need to judice
* @param str never return null
* */
public static String killNull(String str){
return CommonUtils.isNull(str)?"":str.trim();
}
/**把数组里的String元素转换成Integer元素
* @param array 数组
* @return array
* */
public static int[] stringArray2IntArray(String[] array){
int[] result=new int[0];
if(array!=null){
result=new int[array.length];
for(int i=0;i<array.length;i++){
result[i]=Integer.parseInt(array[i]);
}
}
return result;
}
/**把字符串格式化一下，就是拼接字符串的时候把最后一个","之类的东西删掉
* @param str 需要格式化的字符串
* @param flag ","或者什么的，默认是","
* @return 返回格式化后的字符串
* */
public static String format(String str,String flag){
if(CommonUtils.isNull(str)){
return "";
}
StringBuilder sb=new StringBuilder(str);
if(sb.indexOf(flag)>0){
return sb.substring(0,sb.lastIndexOf(flag));
}
return sb.toString();
}
/**把字符串格式化一下，就是拼接字符串的时候把最后一个","之类的东西删掉
* @param str 需要格式化的字符串,默认是","
* @return 返回格式化后的字符串
* */
public static String format(String str){
return format(str,",");
}
/**
* 把一个数字的字符串转换成Int，如果是小数，则强转成int
*
* */
public static int toInt(String x){
return (int)Float.parseFloat(x);
}
/**
* trim方法，不会爆空指针异常，但是近来null，就会返回null
* @param str
* @return str.trim();
* */
public static String trim(String str){
return str==null?null:str.trim();
}
public static <T> Map<String,T> extractSthFieldToMap(List<T> list,String fieldName){
if(CommonUtils.isNull(list)){
return new HashMap<String,T>();
}
Map<String,T> result=new HashMap<String,T>();
for(T t:list){
Object obj=ReflectUtils.getValue(t, fieldName);
result.put(obj==null?null:obj.toString(),t);
}
return result;
}
public static <T> List<String> extractSthField(List<T> list,String fieldName){
if(CommonUtils.isNull(list)){
return null;
}
List<String> result=new ArrayList<String>();
for(T t:list){
Object obj=ReflectUtils.getValue(t, fieldName);
result.add(obj==null?null:obj.toString());
}
return result;
}
}