/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
    *
    * This program and the accompanying materials are dual-licensed under
    * either the terms of the Eclipse Public License v1.0 as published by
    * the Eclipse Foundation
    *
    *   or (per the licensee's choosing)
   *
   * under the terms of the GNU Lesser General Public License version 2.1
   * as published by the Free Software Foundation.
   */
  package ch.qos.logback.core.joran.spi;
  
  import java.util.Map;
  import java.util.Stack;
  
  import ch.qos.logback.core.Context;
  import ch.qos.logback.core.joran.action.Action;
  import ch.qos.logback.core.model.Model;
  import ch.qos.logback.core.spi.ContextAwareBase;
  import ch.qos.logback.core.spi.PropertyContainer;
  import ch.qos.logback.core.spi.ScanException;
  import ch.qos.logback.core.util.OptionHelper;
  
  /**
   * 
   * An InterpretationContext contains the contextual state of a Joran parsing
   * session. {@link Action} objects depend on this context to exchange and store
   * information.
   * 
   * @author Ceki Gülcü
   */
  public class SaxEventInterpretationContext extends ContextAwareBase implements PropertyContainer {
      Stack<Model> modelStack;
  
      SaxEventInterpreter saxEventInterpreter;
  
      public SaxEventInterpretationContext(Context context, SaxEventInterpreter saxEventInterpreter) {
          this.context = context;
          this.saxEventInterpreter = saxEventInterpreter;
          this.modelStack = new Stack<>();
      }
  
      public SaxEventInterpreter getSaxEventInterpreter() {
          return saxEventInterpreter;
      }
  
      /**
       * Return the Model at the top of the model stack, may return null.
       * 
       * @return
       */
      public Model peekModel() {
          if(modelStack.isEmpty()) {
              return null;
          }
          return modelStack.peek();
      }
  
      public void pushModel(Model m) {
          modelStack.push(m);
      }
  
      public boolean isModelStackEmpty() {
          return modelStack.isEmpty();
      }
  
      public Model popModel() {
          return modelStack.pop();
      }
  
      public Stack<Model> getCopyOfModelStack() {
          Stack<Model> copy = new Stack<>();
          copy.addAll(modelStack);
          return copy;
      }
  
      public void addSubstitutionProperty(String key, String value) {
          throw new UnsupportedOperationException();
      }
  
      /**
       * If a key is found in propertiesMap then return it. Otherwise, delegate to the
       * context.
       */
      public String getProperty(String key) {
          return context.getProperty(key);
      }
  
      public Map<String, String> getCopyOfPropertyMap() {
          return null;
      }
  
      public String subst(String value) {
          if (value == null) {
              return null;
          }
 
         try {
             return OptionHelper.substVars(value, this, context);
         } catch (ScanException | IllegalArgumentException e) {
             addError("Problem while parsing [" + value + "]", e);
             return value;
         }
     }
 
 }