content: /**
   * Copyright 2020 Alibaba Group Holding Limited.
   *
   * 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.graphscope.function.test.config;
  
  import com.alibaba.graphscope.function.test.GraphTestException;
  
  import java.io.InputStream;
  import java.util.Map;
  import java.util.Properties;
  
  /**
   * accept a config file and render from system properties, replace all '${}' with system variable value
   */
  public class ConfigTemplateRender {
      private InputStream inputStream;
  
      public ConfigTemplateRender(InputStream inputStream) {
          this.inputStream = inputStream;
      }
  
      public Properties renderFromSysEnv() throws GraphTestException {
          try {
              Properties output = new Properties();
              Properties input = new Properties();
              input.load(inputStream);
              for (Map.Entry<Object, Object> entry : input.entrySet()) {
                  output.setProperty(
                          entry.getKey().toString(), parseFromSysEnv(entry.getValue().toString()));
              }
              return output;
          } catch (Exception e) {
              throw new GraphTestException(e);
          }
      }
  
      private String parseFromSysEnv(String value) {
          StringBuilder builder = new StringBuilder();
          for (int i = 0; i < value.length(); ) {
              char ch = value.charAt(i);
              if (ch == '$' && ++i < value.length() && value.charAt(i) == '{') {
                  int j = i;
                  while (j < value.length() && value.charAt(j) != '}') {
                      ++j;
                  }
                  if (j > i) {
                      String envKey = value.substring(i + 1, j);
                      builder.append(System.getProperty(envKey));
                  }
                  i = j + 1;
              } else {
                  builder.append(ch);
                  ++i;
              }
          }
          return builder.toString();
      }
  }
  