/*
    * 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.river.reggie.proxy;
  
  import org.apache.river.proxy.MarshalledWrapper;
  import org.apache.river.reggie.proxy.ClassMapper.EntryField;
  import java.io.IOException;
  import java.io.InvalidObjectException;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutputStream;
  import java.io.ObjectStreamField;
  import java.io.Serializable;
  import java.lang.reflect.Field;
  import java.rmi.MarshalException;
  import java.rmi.RemoteException;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  import net.jini.core.entry.Entry;
  import org.apache.river.api.io.AtomicSerial;
  import org.apache.river.api.io.AtomicSerial.GetArg;
  import org.apache.river.api.io.Valid;
  
  /**
   * An EntryRep contains the fields of an Entry packaged up for
   * transmission between client-side proxies and the registrar server.
   * Instances are never visible to clients, they are private to the
   * communication between the proxies and the server.
   * <p>
   * This class only has a bare minimum of methods, to minimize
   * the amount of code downloaded into clients.
   *
   * @author Sun Microsystems, Inc.
   *
   */
  @AtomicSerial
  public final class EntryRep implements Serializable, Cloneable {
  
      private static final long serialVersionUID = 2L;
      private static final ObjectStreamField[] serialPersistentFields = 
      { 
          /** @serialField The Class of the Entry converted to EntryClass. */
          new ObjectStreamField("eclass", EntryClass.class),
          /** @serialField The codebase of the entry class. */
          new ObjectStreamField("codebase", String.class),
  	/** @serialField The public fields of the Entry, each converted as necessary to
  	 * a MarshalledWrapper (or left as is if of known java.lang immutable
  	 * type).  The fields are in super- to subclass order. */
          new ObjectStreamField("fields", Object[].class)
      };
  
      /**
       * The Class of the Entry converted to EntryClass.
       *
       * @serial
       */
      public final EntryClass eclass;
      /**
       * The codebase of the entry class.
       * 
       * @serial
       */
      public final String codebase;
      /**
       * The public fields of the Entry, each converted as necessary to
       * a MarshalledWrapper (or left as is if of known java.lang immutable
       * type).  The fields are in super- to subclass order.
       *
       * @serial
       */
      private final Object[] fields; // Individual fields were mutated by RegistrarImpl
  
      transient List flds; // Reggie now uses flds to access fields.
     
      public List fields(){
  	return flds;
      }
      
      private static boolean check(GetArg arg) 
  	    throws IOException, ClassNotFoundException{
  	EntryClass eclass = Valid.notNull(
  	    arg.get("eclass", null, EntryClass.class), 
  	    "eclass cannot be null"
  	); 
 	String codebase = arg.get("codebase", null, String.class); 
 	Object [] fields = Valid.notNull(
 	    arg.get("fields", null, Object[].class), 
 	    "fields array cannot be null"
 	); 
 	return true;
     }
     
     EntryRep(GetArg arg) throws IOException, ClassNotFoundException{
 	this(arg, check(arg));
     }
     
     private EntryRep(GetArg arg, boolean check) 
 	    throws IOException, ClassNotFoundException{
 	eclass = arg.get("eclass", null, EntryClass.class);
 	codebase = arg.get("codebase", null, String.class);
 	fields = Valid.copy(arg.get("fields", null, Object[].class));
 	flds = Collections.synchronizedList(Arrays.asList(fields != null ? fields : new Object[0]));
     }
     
     private void writeObject(ObjectOutputStream out) throws IOException{
 	synchronized (fields){
 	    out.defaultWriteObject();
 	}
     }
     
     /**
      * For clone and Reggie
      */
     public EntryRep(EntryRep copy, boolean replaceEntryClass){
 	eclass = replaceEntryClass ? copy.eclass.getReplacement(): copy.eclass;
 	codebase = copy.codebase;
 	synchronized (copy.fields){
 	    fields = copy.fields.clone();
 	}
 	flds = Collections.synchronizedList(Arrays.asList(fields != null ? fields : new Object[0]));
     }
     
     /**
      * Converts an Entry to an EntryRep.  Any exception that results
      * is bundled up into a MarshalException.
      */
     private EntryRep(Entry entry, boolean needCodebase) throws RemoteException {
 	EntryClassBase ecb = ClassMapper.toEntryClassBase(entry.getClass());
 	eclass = ecb.eclass;
 	codebase = needCodebase ? ecb.codebase : null;
 	try {
 	    EntryField[] efields = ClassMapper.getFields(entry.getClass());
 	    fields = new Object[efields.length];
 	    for (int i = efields.length; --i >= 0; ) {
 		EntryField f = efields[i];
 		Object val = f.field.get(entry);
 		if (f.marshal && val != null)
 		    val = new MarshalledWrapper(val);
 		fields[i] = val;
 	    }
 	} catch (IOException e) {
 	    throw new MarshalException("error marshalling arguments", e);
 	} catch (IllegalAccessException e) {
 	    throw new MarshalException("error marshalling arguments", e);
 	}
 	flds = Collections.synchronizedList(Arrays.asList(fields != null ? fields : new Object[0]));
     }
 
     /**
      * Convert back to an Entry.  If the Entry cannot be constructed,
      * null is returned.  If a field cannot be unmarshalled, it is set
      * to null.
      */
     public Entry get() {
 	try {
 	    Class clazz = eclass.toClass(codebase);
 	    EntryField[] efields = ClassMapper.getFields(clazz);
 	    Entry entry = (Entry)clazz.newInstance();
 	    for (int i = efields.length; --i >= 0; ) {
 		Object val = flds.get(i);
 		EntryField f = efields[i];
 		Field rf = f.field;
 		try {
 		    if (f.marshal && val != null)
 			val = ((MarshalledWrapper) val).get();
 		    rf.set(entry, val);
 		} catch (Throwable e) {
 		    if (e instanceof IllegalArgumentException) {
 			// fix 4872566: work around empty exception message
 			String msg = "unable to assign " +
 			    ((val != null) ?
 				"value of type " + val.getClass().getName() :
 				"null") +
 			    " to field " + rf.getDeclaringClass().getName() +
 			    "." + rf.getName() + " of type " +
 			    rf.getType().getName();
 			e = new ClassCastException(msg).initCause(e);
 		    }
 		    RegistrarProxy.handleException(e);
 		}
 	    }
 	    return entry;
 	} catch (Throwable e) {
 	    RegistrarProxy.handleException(e);
 	}
 	return null;
     }
 
     /**
      * We don't need this in the client or the server, but since we
      * redefine equals we provide a minimal hashCode that works.
      */
     public int hashCode() {
 	return eclass.hashCode();
     }
 
     /**
      * EntryReps are equal if they have the same class and the fields
      * are pairwise equal.  This is really only needed in the server,
      * but it's very convenient to have here.
      */
     public boolean equals(Object obj) {
 	if (obj instanceof EntryRep) {
 	    EntryRep entry = (EntryRep)obj;
 	    if (!eclass.equals(entry.eclass) ||
 		flds.size() != entry.flds.size())
 		return false;
 	    for (int i = flds.size(); --i >= 0; ) {
 		if ((flds.get(i) == null && entry.flds.get(i) != null) ||
 		    (flds.get(i) != null && !flds.get(i).equals(entry.flds.get(i))))
 		    return false;
 	    }	    
 	    return true;
 	}
 	return false;
     }
 
     /**
      * Test if an entry matches a template.  
      */
     public boolean matchEntry(EntryRep tmpl) {
 	if (!tmpl.eclass.isAssignableFrom(eclass) ||
 	    tmpl.flds.size() > flds.size())
 	    return false;
 	for (int i = tmpl.flds.size(); --i >= 0; ) {
 	    if (tmpl.flds.get(i) != null &&
 		!tmpl.flds.get(i).equals(flds.get(i)))
 		return false;
 	}
 	return true;
     }
 
     /**
      * Deep clone (which just means cloning the fields array too).
      * This is really only needed in the server, but it's very
      * convenient to have here.
      */
     @Override
     public Object clone() {
 	return new EntryRep(this, false);
 	}
 
     /**
      * Converts an array of Entry to an array of EntryRep.  If needCodebase
      * is false, then the codebase of every EntryRep will be null.
      */
     public static EntryRep[] toEntryRep(Entry[] entries, boolean needCodebase)
 	throws RemoteException
     {
 	EntryRep[] reps = null;
 	if (entries != null) {
 	    reps = new EntryRep[entries.length];
 	    for (int i = entries.length; --i >= 0; ) {
 		if (entries[i] != null) {
 		    reps[i] = new EntryRep(entries[i], needCodebase);
 		}
 	    }
 	}
 	return reps;
     }
 
     /** Converts an array of EntryRep to an array of Entry. */
     public static Entry[] toEntry(EntryRep[] reps) {
 	Entry[] entries = null;
 	if (reps != null) {
 	    entries = new Entry[reps.length];
 	    for (int i = reps.length; --i >= 0; ) {
 		entries[i] = reps[i].get();
 	    }
 	}
 	return entries;
     }
     
      private void readObject(ObjectInputStream in)
 	throws IOException, ClassNotFoundException
     {
 	in.defaultReadObject();
 	flds = Collections.synchronizedList(Arrays.asList(fields != null ? fields : new Object[0]));
 }
 }