package com.wenchen.hello;

import oracle.kv.KVStore;
import oracle.kv.KVStoreConfig;
import oracle.kv.KVStoreFactory;
import oracle.kv.Key;
import oracle.kv.Value;
import oracle.kv.ValueVersion;

/**
 * An extremely simple KVStore client application that writes and reads a
 * single record.  It can be used to validate an installation.
 *
 * Before running this example program, start a KVStore instance.  The simplest
 * way to do that is to run KV Lite as described in the INSTALL document.  Use
 * the KVStore instance name, host and port for running this program, as
 * follows:
 *
 * java schema.HelloBigDataWorld -store <instance name> \
 *                               -host  <host name>     \
 *                               -port  <port number>
 *
 * For all examples the default instance name is kvstore, the default host name
 * is localhost and the default port number is 5000.  These defaults match the
 * defaults for running kvlite, so the simplest way to run the examples along
 * with kvlite is to omit all parameters.
 */

public class HelloBigDataWorld {
  private final KVStore store;

  /**
   * Runs the HelloBigDataWorld command line program.
   */
  public static void main( String args[ ] ) {
    try {
      HelloBigDataWorld example = new HelloBigDataWorld( args );
      example.runExample( );
    }
    catch ( RuntimeException e ) {
      e.printStackTrace( );
    }
  }

  /**
   * Parses command line args and opens the KVStore.
   */ 
  HelloBigDataWorld( String[ ] argv ) {
    String storeName = "kvstore";
    String hostName  = "localhost";
    String hostPort  = "5000";

    final int nArgs = argv.length;
    int argc = 0;

    while ( argc < nArgs ) {
      final String thisArg = argv[argc++];
      if ( thisArg.equals( "-store" ) ) 
        if ( argc < nArgs ) 
           storeName = argv[argc++];
        else
          usage( "-store requires an argument" );

      else if ( thisArg.equals( "-host" ) )
        if ( argc < nArgs )
           hostName = argv[argc++];
        else
          usage( "-host requires an argument" );
        
      else if ( thisArg.equals( "-port" ) )
        if ( argc < nArgs )
          hostPort = argv[argc++];
        else
          usage( "-port requires an argument" );

      else
        usage( "Unknown argument: " + thisArg );
    }
    store = KVStoreFactory.getStore
      ( new KVStoreConfig( storeName, hostName + ":" + hostPort ) );
  }

    
  private void usage( String message ) {
    System.out.println( "\n" + message + "\n" );
    System.out.println( "usage: " + getClass( ).getName( ) );
    System.out.println( "\t-store <instance name> (default: kvstore) " +
                        "-host <host name> (default: localhost) " +
                        "-port <port number> (default: 5000)" );
    System.exit( 1 );
  }


  /**
   * Performs example operations and closes the KVStore.
   */
  void runExample( ) {
    final String keyString   = "Hello";
    final String valueString = "Big Data World!";

    store.put( Key.createKey( keyString ),
      Value.createValue( valueString.getBytes( ) ) );
    final ValueVersion valueVersion = store.get( Key.createKey( keyString ) );
    System.out.println( keyString + " " +
      new String( valueVersion.getValue( ).getValue( ) ) );
    store.close( );
  }
}