/*******************************************************************************
    * Copyright (c) 2015 LegSem.
    * All rights reserved. This program and the accompanying materials
    * are made available under the terms of the GNU Lesser Public License v2.1
    * which accompanies this distribution, and is available at
    * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
    * 
    * Contributors:
    *     LegSem - initial API and implementation
   ******************************************************************************/
  package com.legstar.coxb.impl;
  
  import com.legstar.coxb.CobolElement;
  import com.legstar.coxb.CobolUsage;
  import com.legstar.coxb.ICobolComplexBinding;
  import com.legstar.coxb.ICobolOctetStreamBinding;
  import com.legstar.coxb.CobolElementVisitor;
  import com.legstar.coxb.common.CBinding;
  import com.legstar.coxb.host.HostException;
  import com.legstar.coxb.util.PictureUtil;
  
  /**
   * This class implements the behavior of a binary cobol element bound to
   * a JAXB byte array property.
   * COBOL elements could be PIC X which were explicitly changed to OCTET_STREAM_ITEM
   * or COBOL special types such as INDEX or POINTERS that we would not be able to
   * map to anything meaningful in Java.
   *
   * @author Fady Moussallam
   * 
   */
  public class COctetStreamBinding extends CBinding
  implements ICobolOctetStreamBinding {
  
      /** The current value for this element. */
      private byte[] mValue =  null;
  
      /**
       * Constructor for a cobol element to java binding.
       * 
       * @param bindingName the identifier for this binding
       * @param jaxbName the name of the bound java property
       * @param jaxbType the type of the bound java property
       * @param cobolAnnotations the cobol annotations for this element
       * @param parentBinding a reference to the parent binding
       */
      public COctetStreamBinding(
              final String bindingName,
              final String jaxbName,
              final Class < ? > jaxbType,
              final CobolElement cobolAnnotations,
              final ICobolComplexBinding parentBinding) {
          super(bindingName, jaxbName, jaxbType, cobolAnnotations, parentBinding);
      }
  
      /** {@inheritDoc} */
      public void accept(final CobolElementVisitor cev)
      throws HostException {
          cev.visit(this);
      }
  
      /** {@inheritDoc} */
      public byte[] getByteArrayValue() throws HostException {
          return mValue;
      }
  
      /** {@inheritDoc} */
      public void setByteArrayValue(final byte[] value)
      throws HostException {
          mValue = value;
      }
  
      /** {@inheritDoc} */
      public int calcByteLength() {
          return calcOctetStreamByteLength(getPicture(), getUsage());
      }
  
      /**
       * Calculates the host byte length for a PIC X(n).
       * @param picture the picture clause
       * @param usage the usage clause
       * @return the host byte length for a PIC X(n)
       */
      public static int calcOctetStreamByteLength(
              final String picture, final String usage) {
          if (usage.equals(CobolUsage.INDEX)) {
              return 4;
          } else if (usage.equals(CobolUsage.POINTER)) {
              return 4;
          } else if (usage.equals(CobolUsage.PROCEDURE_POINTER)) {
              return 8;
          } else if (usage.equals(CobolUsage.FUNCTION_POINTER)) {
              return 4;
          }
          return PictureUtil.getSymbolsNumber('X', picture);
      }
  
      /** {@inheritDoc} */
      public Object getObjectValue(
             final Class < ? > type) throws HostException {
         if (type.equals(byte[].class)) {
             return mValue;
         } else {
             throw new HostException("Attempt to get binding " + getBindingName()
                     + " as an incompatible type " + type);
         }
     }
 
     /** {@inheritDoc} */
     public void setObjectValue(final Object value) throws HostException {
         if (value == null) {
             mValue = null;
             return;
         }
         if (value instanceof byte[]) {
             mValue = (byte[]) value;
         } else {
             throw new HostException("Attempt to set binding " + getBindingName()
                     + " from an incompatible value " + value);
         }
     }
 
     /** {@inheritDoc} */
     public boolean isSet() {
         return (mValue != null);
     }
 }