com.qnoid.java.t0mR.TemplateResultSetHandler.java Source code

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Here is the source code for com.qnoid.java.t0mR.TemplateResultSetHandler.java

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/*
 *  This file is under the licence Attribution-ShareAlike 3.0 Unported 
 *  (CC BY-SA 3.0) http://creativecommons.org/licenses/by-sa/3.0/
 *
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 *      to Share - to copy, distribute and transmit the work
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 *
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 *  or your use of the work).
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 *  distribute the resulting work only under the same or similar license to 
 *  this one.
 *
 *  With the understanding that:
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 *  from the copyright holder.
 *
 *  Public Domain - Where the work or any of its elements is in the public 
 *  domain under applicable law, that status is in no way affected by the 
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package com.qnoid.java.t0mR;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.dbutils.ResultSetHandler;

import com.qnoid.java.t0SA.Column;
import com.qnoid.java.t0SA.Row;

/**
 * @author Markos Charatzas [http://forrst.me/Cue]
 * @date Jan 15, 2011
    
 * This class provides a way to retrieve all the values in a result set based
 * on the columns specified and create a new object of type {@code T} based on 
 * that values
 *
 * Classes extending this class should provide an implementation for the 
 * template method {@link #newType(Row)} which must return the object based on 
 * the row's columns
 * @see ResultSetHandler
 */
public abstract class TemplateResultSetHandler<T> implements ResultSetHandler<T> {
    private final List<Column<?>> columns;

    /**
     * @param columns all columns available in the ResultSet
     */
    public TemplateResultSetHandler(List<Column<?>> columns) {
        this.columns = columns;
    }

    /**
     * This method will iterate through all the columns 
     * (as specified in the constructor) in the result set and provide a single 
     * callback to the {@link #newType(Row)} with a Row object holding all the 
     * column values.
     * 
     * @param rs a ResultSet pointing to the row holding the next instance of {@code T}
     * @return an object of type T as returned by the {@link #newType(Row)}
     * @see ResultSet#next()
     */
    @Override
    public final T handle(ResultSet rs) throws SQLException {
        Row row = new Row();

        for (Column<?> column : this.columns) {
            row.put(column, rs.getObject(column.name()));
        }

        return this.newType(row);
    }

    /**
     * Template method to be overridden and provide the type of object related
     * to the given row.
     * 
     * @param row the row 
     * @return a new object based on the column 
     * @see Row#get(Column)
     */
    protected abstract T newType(Row row);
}