UsingProperties.java

/*
 * Copyright (c) 2004-2013 Tada AB and other contributors, as listed below.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the The BSD 3-Clause License
 * which accompanies this distribution, and is available at
 * http://opensource.org/licenses/BSD-3-Clause
 *
 * Contributors:
 *   Tada AB
 *   Purdue University
 */
package org.postgresql.pljava.example.annotation;

import org.postgresql.pljava.annotation.Function;

import java.io.IOException;
import java.io.InputStream;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Collections;
import java.util.Iterator;
import java.util.Map;
import java.util.Properties;
import java.util.logging.Logger;

import org.postgresql.pljava.ResultSetProvider;

/**
 * An example that retrieves a {@code Properties} resource, and returns
 * (key,value) rows from it by implementing the {@code ResultSetProvider}
 * interface.
 * @author Thomas Hallgren
 */
public class UsingProperties implements ResultSetProvider
{
	private static Logger s_logger = Logger.getAnonymousLogger();
	private final Iterator m_propertyIterator;
	
	public UsingProperties()
	throws IOException
	{
		Properties v = new Properties();
		InputStream propStream = this.getClass().getResourceAsStream("example.properties");
		if(propStream == null)
		{
			s_logger.fine("example.properties was null");
			m_propertyIterator = Collections.EMPTY_SET.iterator();
		}
		else
		{
			v.load(propStream);
			propStream.close();
			s_logger.fine("example.properties has " + v.size() + " entries");
			m_propertyIterator = v.entrySet().iterator();
		}
	}

	public boolean assignRowValues(ResultSet receiver, int currentRow)
			throws SQLException
	{
		if(!m_propertyIterator.hasNext())
		{
			s_logger.fine("no more rows, returning false");
			return false;
		}
		Map.Entry propEntry = (Map.Entry)m_propertyIterator.next();
		receiver.updateString(1, (String)propEntry.getKey());
		receiver.updateString(2, (String)propEntry.getValue());
		// s_logger.fine("next row created, returning true");
		return true;
	}

	/**
	 * Return the contents of the {@code example.properties} resource,
	 * one (key,value) row per entry.
	 */
	@Function( type = "javatest._properties")
	public static ResultSetProvider propertyExampleAnno()
	throws SQLException
	{
		try
		{
			return new UsingProperties();
		}
		catch(IOException e)
		{
			throw new SQLException("Error reading properties", e.getMessage());
		}
	}

	public void close()
	{
	}
}