/*$Id: Vars.java,v 1.7 2004/12/09 16:39:12 clq2 Exp $
    * Created on 28-Jul-2004
    *
    * Copyright (C) AstroGrid. All rights reserved.
    *
    * This software is published under the terms of the AstroGrid 
    * Software License version 1.2, a copy of which has been included 
    * with this distribution in the LICENSE.txt file.  
    *
  **/
  package org.astrogrid.jes.jobscheduler.impl.groovy;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import groovy.lang.Binding;
  import groovy.lang.MissingPropertyException;
  
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  
  /*** represents set of variable bindings in scope.
   * allows additional scopes to be added and removed.
   * scopes introduce new bindings.
   * asignements to existing bindings in parent scopes update, rather than shadow.
   * @author Noel Winstanley nw@jb.man.ac.uk 28-Jul-2004
   *
   */
  public class Vars{
      /***
       * Commons Logger for this class
       */
      private static final Log logger = LogFactory.getLog(Vars.class);
  
      /*** Construct a new Bindings
       * 
       */
      public Vars() {
          super();
          l = new ArrayList();
          l.add(new HashMap());
      }
  
      protected List l;
  
      
      
      public Object get(String name) {
          Map e = findMapWithKey(name);
          if (e == null) {
              return null;
          }
          return e.get(name);
      }
  
      public void set(String name,Object value) {
          Map e = findMapWithKey(name);
          if (e == null) {
              e = getInnermost();
          }
          e.put(name,value);
      }
      
      private Map getInnermost() {
          return (Map)l.get(l.size()  -1);
      }
      private Map findMapWithKey(String name) {
          for (int i = l.size() - 1; i >= 0; i--) {
              Map m = (Map)l.get(i);
              if (m.containsKey(name)) {
                  return m;
              }
          }
          return null;
      }
      
      
      public void unset(String name) {
          Map e = findMapWithKey(name);
          if (e !=null) {
              e.remove(name);
          }
      }
      /*** Branch these vars
       * this is a very shallow copy. existing scopes are shared between the original and copy.
       * however, new scopes in the copy do not appear in the original.
       */
      public Vars branchVars() {
          Vars copy = new Vars();
          copy.l.clear();
          copy.l.addAll(this.l);
          return copy;
      }
      
  public void newScope() {
      l.add(new HashMap());
 }
 
 public void removeScope()     {
     l.remove(l.size() - 1);
 }
     
 
     /*** Add the variables defined in this collection to a binding, plus the 'vars' object itself.
      * @param bodyBinding
      */
     public void addToBinding(Binding bodyBinding) {
         /*** NWW - 9/12/04 don't like this - not necessary - problematic
         bodyBinding.setVariable("vars",this);
         */
         for (Iterator j = l.iterator(); j.hasNext(); ) {
             Map e = (Map)j.next();
             for (Iterator i = e.entrySet().iterator(); i.hasNext(); ) {
                 Map.Entry var = (Map.Entry)i.next();
                 bodyBinding.setVariable(var.getKey().toString(),var.getValue());
             }
         }
     }
 
     /*** Find the variables defined in this collection in the binding, copy back across again.
      *<p>
      *any new variables defined in the script must have been done directly - through accessing this object already. so just need to look for the values of existing vars.
      * @param bodyBinding
      */
     
     public void readFromBinding(Binding bodyBinding) {
         for (int j = 0; j < l.size(); j++){
             Map e = (Map)l.get(j);           
             for (Iterator i = e.entrySet().iterator(); i.hasNext(); ) {
                 Map.Entry var = (Map.Entry)i.next();
                 try {
                     Object newValue = bodyBinding.getVariable(var.getKey().toString());
                     var.setValue(newValue);
                 } catch (MissingPropertyException missing) {
                     /*** don't think this is possible */
                     logger.warn(missing);
                 }
             }
     }
     
     /* beta-6 need a different impleemntation for beta-7 - as empty vars throws expcetions
     public void readFromBinding(Binding bodyBinding) {
         for (int j = 0; j < l.size(); j++){
             Map e = (Map)l.get(j);           
             for (Iterator i = e.entrySet().iterator(); i.hasNext(); ) {
                 Map.Entry var = (Map.Entry)i.next();
                 Object newValue = bodyBinding.getVariable(var.getKey().toString());
                 if (newValue == null) {
                 // dunno if its been explicitly set to null, or whether its a new binding added by the script. arse.
                 // safest thing is to ignore this.
                 //var.setValue(null);
                 } else {
                     var.setValue(newValue);
                 }
             }
         }*/
     }
     
 
     /***
      * Override hashCode.
      *
      * @return the Objects hashcode.
      */
     public int hashCode() {
         int hashCode = 1;
         hashCode = 31 * hashCode + (l == null ? 0 : l.hashCode());
         return hashCode;
     }
     public String toString() {
         StringBuffer buffer = new StringBuffer();
         buffer.append("[Vars:");
         buffer.append(" l: ");
         buffer.append(l);
         buffer.append("]");
         return buffer.toString();
     }
     /***
      * Returns <code>true</code> if this <code>Vars</code> is the same as the o argument.
      *
      * @return <code>true</code> if this <code>Vars</code> is the same as the o argument.
      */
     public boolean equals(Object o) {
         if (this == o) {
             return true;
         }
         if (o == null) {
             return false;
         }
         if (o.getClass() != getClass()) {
             return false;
         }
         Vars castedObj = (Vars) o;
         return ((this.l == null ? castedObj.l == null : this.l
             .equals(castedObj.l)));
     }
 }
 
 
 /* 
 $Log: Vars.java,v $
 Revision 1.7  2004/12/09 16:39:12  clq2
 nww_jes_panic
 
 Revision 1.6.4.1  2004/12/09 13:22:59  nw
 made variable persistance a little harder.
 
 Revision 1.6  2004/11/29 20:00:24  clq2
 jes-nww-714
 
 Revision 1.5.12.1  2004/11/26 01:31:18  nw
 updated dependency on groovy to 1.0-beta7.
 updated code and tests to fit.
 
 Revision 1.5  2004/11/05 16:52:42  jdt
 Merges from branch nww-itn07-scratchspace
 
 Revision 1.4.58.1  2004/11/05 16:03:57  nw
 optimized: uses int rather than iterator
 
 Revision 1.4  2004/08/09 17:34:10  nw
 implemented parfor.
 removed references to rulestore
 
 Revision 1.3  2004/08/03 14:27:38  nw
 added set/unset/scope features.
 
 Revision 1.2  2004/07/30 15:42:34  nw
 merged in branch nww-itn06-bz#441 (groovy scripting)
 
 Revision 1.1.2.3  2004/07/30 15:10:04  nw
 removed policy-based implementation,
 adjusted tests, etc to use groovy implementation
 
 Revision 1.1.2.2  2004/07/30 14:00:10  nw
 first working draft
 
 Revision 1.1.2.1  2004/07/28 16:24:23  nw
 finished groovy beans.
 moved useful tests from old python package.
 removed python implemntation
  
 */