content: /*
   * Copyright 2010-2025 Hyland Software, Inc. and its affiliates.
   *
   * 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 org.activiti.spring.resolver;
  
  import jakarta.el.ELContext;
  import jakarta.el.ELResolver;
  
  public class EnvironmentVariableELResolver extends ELResolver {
  
      private static final String VAR_PREFIX = "vars";
      public static final String VAR_PREFIX_WITH_DOT = VAR_PREFIX + ".";
  
      @Override
      public Object getValue(ELContext context, Object base, Object property) {
          if (base == null && VAR_PREFIX.equals(property)) {
              context.setPropertyResolved(true);
              return new EnvVar();
          }
          if (base instanceof EnvVar && property != null) {
              String env = System.getenv(VAR_PREFIX_WITH_DOT + property);
              context.setPropertyResolved(true);
              return env;
          }
          return null;
      }
  
      @Override
      public Class<?> getType(ELContext elContext, Object o, Object o1) {
          return String.class;
      }
  
      @Override
      public void setValue(ELContext elContext, Object o, Object o1, Object o2) {
          throw new UnsupportedOperationException("Environment variables are read-only");
      }
  
      @Override
      public boolean isReadOnly(ELContext elContext, Object o, Object o1) {
          return true;
      }
  
      @Override
      public Class<?> getCommonPropertyType(ELContext elContext, Object o) {
          return String.class;
      }
  }
  