Android Open Source - DKO Dual Iterator

• Back to Database/orm  ↑

From Project

Back to project page DKO.

License

The source code is released under:

GNU Lesser General Public License

Java Source Code

package org.kered.dko;
//from   w w w  . j a  v  a  2s .  c  om
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;

import javax.sql.DataSource;

class DualIterator {

  private Connection conn;
  private PreparedStatement ps;
  private ResultSet rs;
  private boolean done = false;
  private boolean finishedNatually = false;
  private Queue<Object[]> leftQueue = new LinkedList<Object[]>();
  private Queue<Object[]> rightQueue = new LinkedList<Object[]>();
  InternalIterator leftIterator = new InternalIterator(leftQueue);
  InternalIterator rightIterator = new InternalIterator(rightQueue);
  private List<Field<?>> qLfields;
  private List<Field<?>> qRfields;
  private PeekableClosableIterator<Object[]> iterator = null;

  public DualIterator(DataSource ds, String sql, List<Field<?>> qLfields, List<Field<?>> qRfields) {
    this.qLfields = qLfields;
    this.qRfields = qRfields;
      Util.log(sql, null);
      try {
        conn = ds.getConnection();
        ps = conn.prepareStatement(sql);
        rs = ps.executeQuery();
      } catch (SQLException e) {
        throw new RuntimeException(e);
      }
  }

  public DualIterator(PeekableClosableIterator<Object[]> iterator, List<Field<?>> qLfields, List<Field<?>> qRfields) {
    this.qLfields = qLfields;
    this.qRfields = qRfields;
    conn = null;
    ps = null;
    rs = null;
    this.iterator = iterator;
  }

  public PeekableClosableIterator<Object[]> getLeftIterator() {
    return leftIterator;
  }

  public PeekableClosableIterator<Object[]> getRightIterator() {
    return rightIterator;
  }

  @Override
  protected void finalize() throws Throwable {
    if (!done) close();
    super.finalize();
  }

  public synchronized void close() {
    if (done) return;
    if (iterator!=null) iterator.close();
    try {
      if (!finishedNatually && rs!=null && ps!=null && !rs.isClosed()) {
        ps.cancel();
      }
    } catch (SQLException e2) {
      e2.printStackTrace();
    } catch (AbstractMethodError e) {
      if ("org.sqlite.RS".equals(rs.getClass().getName())) {
        // ignore - bad jdbc driver
      } else {
        throw e;
      }
    }
    try {
      if (rs!=null && !rs.isClosed()) rs.close();
    } catch (SQLException e2) {
      e2.printStackTrace();
    } catch (AbstractMethodError e) {
      if ("org.sqlite.RS".equals(rs.getClass().getName())) {
        // ignore - bad jdbc driver
      } else {
        throw e;
      }
    }
    try {
      if (ps!=null && !ps.isClosed()) ps.close();
    } catch (SQLException e1) {
      e1.printStackTrace();
    } catch (AbstractMethodError e) {
      if ("org.sqlite.RS".equals(rs.getClass().getName())) {
        // ignore - bad jdbc driver
      } else {
        throw e;
      }
    }
    try {
      if (conn!=null && !conn.isClosed()) conn.close();
    } catch (final SQLException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
    done = true;
  }
  
  public class InternalIterator implements PeekableClosableIterator<Object[]> {

    private Queue<Object[]> queue;
    private boolean closed = false;

    public InternalIterator(Queue<Object[]> queue) {
      this.queue = queue;
    }

    @Override
    public boolean hasNext() {
      if (queue.isEmpty()) getNextRow();
      return !queue.isEmpty();
    }

    @Override
    public Object[] next() {
      return queue.poll();
    }

    @Override
    public void remove() {
      throw new UnsupportedOperationException();
    }

    @Override
    public void close() {
      this.closed = true;
      if (leftIterator.closed && rightIterator.closed) {
        DualIterator.this.close();
      }
    }

    @Override
    public Object[] peek() {
      return queue.peek();
    }
    
  }

  public void getNextRow() {
    if (rs!=null) {
      try {
        if (!rs.next()) return;
        int leftSize = qLfields.size();
        final Object[] leftRow = new Object[leftSize];
        for (int i=0; i<leftSize; ++i) {
          leftRow[i] = Util.getTypedValueFromRS(rs, i+1, qLfields.get(i));
        }
        leftQueue.add(leftRow);
        int rightSize = qRfields.size();
        final Object[] rightRow = new Object[rightSize];
        for (int i=0; i<rightSize; ++i) {
          rightRow[i] = Util.getTypedValueFromRS(rs, leftSize+i+1, qRfields.get(i));
        }
        rightQueue.add(rightRow);
      } catch (SQLException e) {
        throw new RuntimeException(e);
      }
    } else if (iterator!=null) {
      if (!iterator.hasNext()) return;
      Object[] row = iterator.next();
      int leftSize = qLfields.size();
      final Object[] leftRow = new Object[leftSize];
      System.arraycopy(row, 0, leftRow, 0, leftSize);
      leftQueue.add(leftRow);
      int rightSize = qRfields.size();
      final Object[] rightRow = new Object[rightSize];
      System.arraycopy(row, leftSize, rightRow, 0, rightSize);
      rightQueue.add(rightRow);
    }
  }

}

Java Source Code List

• Back to Database/orm  ↑