/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.apache.myfaces.view.facelets.compiler;
  
  import java.io.IOException;
  
  import javax.el.ELContext;
  import javax.el.ELException;
  import javax.el.ExpressionFactory;
  import javax.faces.context.FacesContext;
  import javax.faces.context.ResponseWriter;
  
  import org.apache.myfaces.view.facelets.el.ELText;
  
  final class AttributeInstruction implements Instruction
  {
      private final String _alias;
  
      private final String _attr;
  
      private final ELText _txt;
  
      public AttributeInstruction(String alias, String attr, ELText txt)
      {
          _alias = alias;
          _attr = attr;
          _txt = txt;
      }
  
      public void write(FacesContext context) throws IOException
      {
          ResponseWriter out = context.getResponseWriter();
          try
          {
              out.writeAttribute(_attr, _txt.toString(context.getELContext()), null);
          }
          catch (ELException e)
          {
              throw new ELException(_alias + ": " + e.getMessage(), e.getCause());
          }
          catch (Exception e)
          {
              throw new ELException(_alias + ": " + e.getMessage(), e);
          }
      }
  
      public Instruction apply(ExpressionFactory factory, ELContext ctx)
      {
          ELText nt = _txt.apply(factory, ctx);
          if (nt == _txt)
          {
              return this;
          }
  
          return new AttributeInstruction(_alias, _attr, nt);
      }
  
      public boolean isLiteral()
      {
          return _txt.isLiteral();
      }
  }