content: /*
   * Copyright 1999-2018 Alibaba Group Holding Ltd.
   *
   * 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.alibaba.nacos.common.http.param;
  
  import com.alibaba.nacos.common.utils.MapUtil;
  
  import java.io.UnsupportedEncodingException;
  import java.net.URLEncoder;
  import java.util.LinkedHashMap;
  import java.util.Map;
  import java.util.Set;
  
  /**
   * Http Query object.
   *
   * @author <a href="mailto:liaochuntao@live.com">liaochuntao</a>
   */
  public class Query {
      
      private boolean isEmpty = true;
      
      public static final Query EMPTY = Query.newInstance();
      
      private Map<String, Object> params;
      
      private static final String DEFAULT_ENC = "UTF-8";
      
      public Query() {
          params = new LinkedHashMap<>();
      }
      
      public static Query newInstance() {
          return new Query();
      }
      
      /**
       * Add query parameter.
       *
       * @param key   key
       * @param value value
       * @return this query
       */
      public Query addParam(String key, Object value) {
          isEmpty = false;
          params.put(key, value);
          return this;
      }
      
      public Object getValue(String key) {
          return params.get(key);
      }
      
      /**
       * Add all parameters as query parameter.
       *
       * @param params parameters
       * @return this query
       */
      public Query initParams(Map<String, String> params) {
          if (MapUtil.isNotEmpty(params)) {
              for (Map.Entry<String, String> entry : params.entrySet()) {
                  addParam(entry.getKey(), entry.getValue());
              }
          }
          return this;
      }
      
      /**
       * Print query as a http url param string. Like K=V&K=V.
       *
       * @return http url param string
       */
      public String toQueryUrl() {
          StringBuilder urlBuilder = new StringBuilder();
          Set<Map.Entry<String, Object>> entrySet = params.entrySet();
          int i = entrySet.size();
          for (Map.Entry<String, Object> entry : entrySet) {
              try {
                  if (null != entry.getValue()) {
                      urlBuilder.append(entry.getKey()).append('=')
                              .append(URLEncoder.encode(String.valueOf(entry.getValue()), DEFAULT_ENC));
                      if (i > 1) {
                          urlBuilder.append('&');
                      }
                  }
                  i--;
              } catch (UnsupportedEncodingException e) {
                  throw new RuntimeException(e);
              }
          }
          
          return urlBuilder.toString();
      }
      
      public void clear() {
          params.clear();
          isEmpty = true;
      }
      
      public boolean isEmpty() {
          return isEmpty;
      }
      
  }
  