PlaceholderUtil

package com.izkml.mlyun.core.tool.util;

import java.util.Map;
import java.util.Properties;
import java.util.function.Function;
import java.util.stream.Stream;

/**
 * 占位符解析器
 *
 * @author atom
 */
public class PlaceholderUtil {
   /**
    * 默认前缀占位符
    */
   public static final String DEFAULT_PLACEHOLDER_PREFIX = "${";

   /**
    * 默认后缀占位符
    */
   public static final String DEFAULT_PLACEHOLDER_SUFFIX = "}";

   /**
    * 默认单例解析器
    */
   private static PlaceholderUtil defaultResolver = new PlaceholderUtil();

   /**
    * 占位符前缀
    */
   private String placeholderPrefix = DEFAULT_PLACEHOLDER_PREFIX;

   /**
    * 占位符后缀
    */
   private String placeholderSuffix = DEFAULT_PLACEHOLDER_SUFFIX;


   private PlaceholderUtil() {
   }

   private PlaceholderUtil(String placeholderPrefix, String placeholderSuffix) {
      this.placeholderPrefix = placeholderPrefix;
      this.placeholderSuffix = placeholderSuffix;
   }

   /**
    * 获取默认的占位符解析器，即占位符前缀为"${", 后缀为"}"
    *
    * @return
    */
   public static PlaceholderUtil getDefaultResolver() {
      return defaultResolver;
   }

   public static PlaceholderUtil getResolver(String placeholderPrefix, String placeholderSuffix) {
      return new PlaceholderUtil(placeholderPrefix, placeholderSuffix);
   }

   /**
    * 解析带有指定占位符的模板字符串，默认占位符为前缀：${  后缀：}<br/><br/>
    * 如：template = category:${}:product:${}<br/>
    * values = {"1", "2"}<br/>
    * 返回 category:1:product:2<br/>
    *
    * @param content 要解析的带有占位符的模板字符串
    * @param values  按照模板占位符索引位置设置对应的值
    * @return
    */
   public String resolve(String content, String... values) {
      int start = content.indexOf(this.placeholderPrefix);
      if (start == -1) {
         return content;
      }
      //值索引
      int valueIndex = 0;
      StringBuilder result = new StringBuilder(content);
      while (start != -1) {
         int end = result.indexOf(this.placeholderSuffix);
         String replaceContent = values[valueIndex++];
         result.replace(start, end + this.placeholderSuffix.length(), replaceContent);
         start = result.indexOf(this.placeholderPrefix, start + replaceContent.length());
      }
      return result.toString();
   }

   /**
    * 解析带有指定占位符的模板字符串，默认占位符为前缀：${  后缀：}<br/><br/>
    * 如：template = category:${}:product:${}<br/>
    * values = {"1", "2"}<br/>
    * 返回 category:1:product:2<br/>
    *
    * @param content 要解析的带有占位符的模板字符串
    * @param values  按照模板占位符索引位置设置对应的值
    * @return
    */
   public String resolve(String content, Object[] values) {
      return resolve(content, Stream.of(values).map(String::valueOf).toArray(String[]::new));
   }

   /**
    * 根据替换规则来替换指定模板中的占位符值
    *
    * @param content 要解析的字符串
    * @param rule    解析规则回调
    * @return
    */
   public String resolveByRule(String content, Function<String, String> rule) {
      int start = content.indexOf(this.placeholderPrefix);
      if (start == -1) {
         return content;
      }
      StringBuilder result = new StringBuilder(content);
      while (start != -1) {
         int end = result.indexOf(this.placeholderSuffix, start + 1);
         //获取占位符属性值，如${id}, 即获取id
         String placeholder = result.substring(start + this.placeholderPrefix.length(), end);
         //替换整个占位符内容，即将${id}值替换为替换规则回调中的内容
         String replaceContent = placeholder.trim().isEmpty() ? "" : rule.apply(placeholder);
         result.replace(start, end + this.placeholderSuffix.length(), replaceContent);
         start = result.indexOf(this.placeholderPrefix, start + replaceContent.length());
      }
      return result.toString();
   }

   /**
    * 替换模板中占位符内容，占位符的内容即为map key对应的值，key为占位符中的内容。<br/><br/>
    * 如：content = product:${id}:detail:${did}<br/>
    * valueMap = id -> 1; pid -> 2<br/>
    * 经过解析返回 product:1:detail:2<br/>
    *
    * @param content  模板内容。
    * @param valueMap 值映射
    * @return 替换完成后的字符串。
    */
   public String resolveByMap(String content, final Map<String, Object> valueMap) {
      return resolveByRule(content, placeholderValue -> String.valueOf(valueMap.get(placeholderValue)));
   }

   /**
    * 根据properties文件替换占位符内容
    *
    * @param content
    * @param properties
    * @return
    */
   public String resolveByProperties(String content, final Properties properties) {
      return resolveByRule(content, properties::getProperty);
   }

}