content: package com.airhacks.enhydrator.transform;
  
  /*
   * #%L
   * enhydrator
   * %%
   * Copyright (C) 2014 Adam Bien
   * %%
   * 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.
   * #L%
   */
  import com.airhacks.enhydrator.in.Row;
  import java.util.Map;
  import java.util.function.Consumer;
  import javax.script.Bindings;
  import javax.script.ScriptEngine;
  import javax.script.ScriptEngineManager;
  import javax.script.ScriptException;
  
  /**
   *
   * @author airhacks.com
   */
  public class FilterExpression {
  
      private final ScriptEngineManager manager;
      private final ScriptEngine engine;
      private final Map<String, Object> scriptEngineBindings;
      private Consumer<String> expressionListener;
  
      public FilterExpression() {
          this(l -> {
          }, null);
      }
  
      public FilterExpression(Consumer<String> expressionListener, Map<String, Object> scriptEngineBindings) {
          this.expressionListener = expressionListener;
          this.manager = new ScriptEngineManager();
          this.engine = manager.getEngineByName("nashorn");
          this.scriptEngineBindings = scriptEngineBindings;
      }
  
      public Boolean execute(Row columns, String expression) {
          Bindings bindings = ScriptingEnvironmentProvider.create(this.manager, this.scriptEngineBindings, columns);
          try {
              this.expressionListener.accept("Executing: " + expression);
              Object result = this.engine.eval(expression, bindings);
              this.expressionListener.accept("Got result: " + result);
              if (!(result instanceof Boolean)) {
                  return Boolean.FALSE;
              } else {
                  return (Boolean) result;
              }
          } catch (ScriptException ex) {
              throw new IllegalStateException(ex.getMessage(), ex);
          }
      }
  }
  