Android Open Source - ormada Forward Only Result Set Cursor

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License

The source code is released under:

Copyright (c) 2012 Jesse Rosalia Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Sof...

Java Source Code

package org.ormada.dialect;
/*from  w ww .j  a v  a 2 s. com*/
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;

/**
 * A generic QueryCursor implementation for "forward only" JDBC ResultSet objects.
 * 
 * Forward only ResultSets only support a handful of the functions defined in the ResultSet
 * object.  Sucks to be us.  This class is written accordingly, to build an intelligent cursor
 * using only the next() function.  Note that because of this, the cursor will be "forward only", 
 * in that it cannot be rewound or replayed.  This should be ok for our ORM implementation.
 * 
 * NOTE: JDBC uses 1 based column indexing, and the ORM framework uses 0 based indexing.  This class adjusts for that.
 * @author Jesse Rosalia
 *
 */
public class ForwardOnlyResultSetCursor implements QueryCursor {

    private ResultSet         resultSet;
    private ResultSetMetaData rsMetaData;
    private boolean first;
    private boolean next;

    public ForwardOnlyResultSetCursor(ResultSet resultSet) throws SQLException {
        this.resultSet  = resultSet;
        this.rsMetaData = resultSet.getMetaData();
        
        this.first = this.resultSet.next();
        this.next  = this.first;
    }

    @Override
  public void close() {
        try {
            this.resultSet.close();
        } catch (SQLException e) {
            //we're closing...nothing to do
        }
  }

  @Override
  public boolean isEmpty() {
      //FIXME: this isnt right, as this will return true after moving past the first element
        return !this.first;
  }

  @Override
  public boolean moveToFirst() {
    try {
            return this.first;
        } finally {
            this.first = false;
        }
  }

  @Override
  public boolean isAfterLast() {
        return !this.next;
  }

  @Override
  public boolean moveToNext() {
        try {
            this.next = this.resultSet.next();
        } catch (SQLException e) {
            e.printStackTrace();
            this.next = false;
        }
        return this.next;
  }

  @Override
  public int getColumnCount() throws SQLException {
      return this.rsMetaData.getColumnCount();
  }

  @Override
  public String getColumnName(int col) throws SQLException {
      return this.rsMetaData.getColumnLabel(col + 1);
  }

  @Override
  public long getLong(int col) throws SQLException {
    return this.resultSet.getLong(col + 1);
  }

  @Override
  public int getInt(int col) throws SQLException {
    return this.resultSet.getInt(col + 1);
  }

  @Override
  public short getShort(int col) throws SQLException {
    return this.resultSet.getShort(col + 1);
  }

  @Override
  public float getFloat(int col) throws SQLException {
    return this.resultSet.getFloat(col + 1);
  }

  @Override
  public double getDouble(int col) throws SQLException {
    return this.resultSet.getDouble(col + 1);
  }

  @Override
  public byte[] getBlob(int col) throws SQLException {
    return this.resultSet.getBytes(col + 1);
  }

  @Override
  public String getString(int col) throws SQLException {
    return this.resultSet.getString(col + 1);
  }
}

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