resultsetiterator.java

实现了从Google

/*
 * $Header: /home/cvs/jakarta-commons/dbutils/src/java/org/apache/commons/dbutils/ResultSetIterator.java,v 1.1 2003/11/02 19:15:23 dgraham Exp $
 * $Revision: 1.1 $
 * $Date: 2003/11/02 19:15:23 $
 * 
 * ====================================================================
 *
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2002-2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowledgement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgement may appear in the software itself,
 *    if and wherever such third-party acknowledgements normally appear.
 *
 * 4. The names "The Jakarta Project", "Commons", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact [e-mail].
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 * 5. Products derived from this software may not be called "Apache"
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 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * This software consists of voluntary contributions made by many
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package org.apache.commons.dbutils;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Iterator;

/**
 * <p>
 * Wraps a <code>ResultSet</code> in an <code>Iterator</code>.  This is useful
 * when you want to present a non-database application layer with domain
 * neutral data.
 * </p>
 * 
 * <p>
 * This implementation requires the <code>ResultSet.isLast()</code> method
 * to be implemented.
 * </p>
 * 
 * @author Henri Yandell
 * @author David Graham
 */
public class ResultSetIterator implements Iterator {

    /**
     * The wrapped <code>ResultSet</code>.
     */
    private ResultSet rs = null;
    
    /**
     * The processor to use when converting a row into an Object[].
     */
    private RowProcessor convert = BasicRowProcessor.instance();

    /**
     * Constructor for ResultSetIterator.
     * @param rs Wrap this <code>ResultSet</code> in an <code>Iterator</code>.
     */
    public ResultSetIterator(ResultSet rs) {
        this.rs = rs;
    }
    
    /**
     * Constructor for ResultSetIterator.
     * @param rs Wrap this <code>ResultSet</code> in an <code>Iterator</code>.
     * @param convert The processor to use when converting a row into an 
     * <code>Object[]</code>.  Defaults to a 
     * <code>BasicRowProcessor</code>.
     */
    public ResultSetIterator(ResultSet rs, RowProcessor convert) {
        this.rs = rs;
        this.convert = convert;
    }

    public boolean hasNext() {
        try {
            return !rs.isLast();

        } catch (SQLException e) {
            //e.printStackTrace();
            return false;
        }
    }

    /**
     * Returns the next row as an <code>Object[]</code>.
     * @return An <code>Object[]</code> with the same number of elements as
     * columns in the <code>ResultSet</code>. 
     * @see java.util.Iterator#next()
     */
    public Object next() {
        try {
            rs.next();
            return this.convert.toArray(rs);

        } catch (SQLException e) {
            //e.printStackTrace();
            return null;
        }
    }

    /**
     * Deletes the current row from the <code>ResultSet</code>.
     * @see java.util.Iterator#remove()
     */
    public void remove() {
        try {
            this.rs.deleteRow();

        } catch (SQLException e) {
            //e.printStackTrace();
        }
    }

}