/*
    *   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.directory.server.xdbm.search.cursor;
  
  
  import java.io.IOException;
  
  import org.apache.directory.api.ldap.model.constants.Loggers;
  import org.apache.directory.api.ldap.model.cursor.Cursor;
  import org.apache.directory.api.ldap.model.cursor.CursorException;
  import org.apache.directory.api.ldap.model.exception.LdapException;
  import org.apache.directory.server.core.api.partition.PartitionTxn;
  import org.apache.directory.server.core.partition.impl.btree.IndexCursorAdaptor;
  import org.apache.directory.server.xdbm.AbstractIndexCursor;
  import org.apache.directory.server.xdbm.IndexEntry;
  import org.apache.directory.server.xdbm.Store;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * A Cursor over all entries in a partition which returns IndexEntries.
   *
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class AllEntriesCursor extends AbstractIndexCursor<String>
  {
      /** A dedicated log for cursors */
      private static final Logger LOG_CURSOR = LoggerFactory.getLogger( Loggers.CURSOR_LOG.getName() );
  
      /** Speedup for logs */
      private static final boolean IS_DEBUG = LOG_CURSOR.isDebugEnabled();
  
      /** The index entry we use to return entries one by one.  */
      private IndexEntry<String, String> indexEntry = new IndexEntry<>();
  
      /** The cursor on the MsterTable index */
      private final Cursor<IndexEntry<String, String>> wrapped;
  
  
      /**
       * {@inheritDoc}
       */
      protected String getUnsupportedMessage()
      {
          return UNSUPPORTED_MSG;
      }
  
  
      /**
       * Creates a new instance of AllEntriesCursor
       * 
       * @param partitionTxn The transaction to use
       * @param store The Store instance
       * @throws LdapException If we weren't able to create an instance of AllEntriesCursor
       */
      public AllEntriesCursor( PartitionTxn partitionTxn, Store store ) throws LdapException
      {
          if ( IS_DEBUG )
          {
              LOG_CURSOR.debug( "Creating AllEntriesCursor {}", this );
          }
          
          this.partitionTxn = partitionTxn;
  
          // Uses the MasterTable 
          wrapped = new IndexCursorAdaptor( partitionTxn, store.getMasterTable().cursor(), true );
      }
  
  
      /**
       * {@inheritDoc}
       */
      @Override
      public void after( IndexEntry<String, String> indexEntry ) throws LdapException, CursorException
      {
          checkNotClosed();
      }
  
  
      /**
       * {@inheritDoc}
      */
     public void afterLast() throws LdapException, CursorException
     {
         checkNotClosed();
 
         wrapped.afterLast();
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public boolean available()
     {
         return wrapped.available();
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void before( IndexEntry<String, String> indexEntry ) throws LdapException, CursorException
     {
         checkNotClosed();
     }
 
 
     /**
      * {@inheritDoc}
      */
     public void beforeFirst() throws LdapException, CursorException
     {
         checkNotClosed();
 
         wrapped.beforeFirst();
     }
 
 
     /**
      * {@inheritDoc}
      */
     public boolean first() throws LdapException, CursorException
     {
         checkNotClosed();
 
         return wrapped.first();
     }
 
 
     /**
      * {@inheritDoc}
      */
     public IndexEntry<String, String> get() throws CursorException
     {
         checkNotClosed();
 
         // Create the returned IndexEntry, copying what we get from the wrapped cursor
         // As we are using the MasterTable, we have to use the key as the 
         // ID and value
         IndexEntry<?, String> wrappedEntry = wrapped.get();
         indexEntry.setId( ( String ) wrappedEntry.getKey() );
         indexEntry.setKey( ( String ) wrappedEntry.getKey() );
         indexEntry.setEntry( null );
 
         return indexEntry;
     }
 
 
     /**
      * {@inheritDoc}
      */
     public boolean last() throws LdapException, CursorException
     {
         checkNotClosed();
 
         return wrapped.last();
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public boolean next() throws LdapException, CursorException
     {
         checkNotClosed();
 
         return wrapped.next();
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public boolean previous() throws LdapException, CursorException
     {
         checkNotClosed();
 
         return wrapped.previous();
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void close() throws IOException
     {
         if ( IS_DEBUG )
         {
             LOG_CURSOR.debug( "Closing AllEntriesCursor {}", this );
         }
 
         wrapped.close();
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void close( Exception cause ) throws IOException
     {
         if ( IS_DEBUG )
         {
             LOG_CURSOR.debug( "Closing AllEntriesCursor {}", this );
         }
 
         wrapped.close( cause );
     }
 
 
     /**
      * @see Object#toString()
      */
     @Override
     public String toString( String tabs )
     {
         StringBuilder sb = new StringBuilder();
 
         sb.append( tabs ).append( "AllEntriesCursor (" );
 
         if ( available() )
         {
             sb.append( "available)" );
         }
         else
         {
             sb.append( "absent)" );
         }
 
         sb.append( " :\n" );
 
         sb.append( wrapped.toString( tabs + "    " ) );
 
         return sb.toString();
     }
 
 
     /**
      * @see Object#toString()
      */
     public String toString()
     {
         return toString( "" );
     }
 }