That's great!
We as a project need to work out what to do with non-core things like
this - I am sure since it was useful to you, it will be useful to many
others. (Yo, Paulo!)
Anyway, there are a few other things floating around that are non-core/
non-basic but need to be kept somewhere.
If we set up a site / place for non-officially-supported contributions /
accessories, would you be willing to commit to support it?
geir
David Kinnvall wrote:
>
> Hi people,
>
> below is my shot at a DBResourceLoader for Velocity.
> I needed this for the project I am currently involved in
> and figured it might be useful for others as well. Could
> you please have a look and perhaps consider it for inclusion
> into the main Velocity tree if it's not too shabby?
>
> Regards,
>
> David.
>
> velocity.properties snippet for configuring it:
>
> #---
> # DBResourceLoader config
> #---
> #
> resource.loader.2.public.name = DB
> resource.loader.2.description = Velocity DB Resource Loader
> resource.loader.2.class =
> org.apache.velocity.runtime.resource.loader.DBResourceLoader
> resource.loader.2.resource.datasource = jdbc/SomeDS
> resource.loader.2.resource.table = template_table
> resource.loader.2.resource.keycolumn = template_id
> resource.loader.2.resource.templatecolumn = template_definition
> resource.loader.2.resource.timestampcolumn = template_timestamp
> resource.loader.2.cache = false
> resource.loader.2.modificationCheckInterval = 2
>
> and DBResourceLoader.java itself:
>
> package org.apache.velocity.runtime.resource.loader;
> /*
> * The Apache Software License, Version 1.1
> *
> * Copyright (c) 2000 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 acknowlegement:
> * "This product includes software developed by the
> * Apache Software Foundation (http://www.apache.org/)."
> * Alternately, this acknowlegement may appear in the software itself,
> * if and wherever such third-party acknowlegements normally appear.
> *
> * 4. The names "The Jakarta Project", "Tomcat", 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 [EMAIL PROTECTED]
> *
> * 5. Products derived from this software may not be called "Apache"
> * nor may "Apache" appear in their names without prior written
> * permission of the Apache Group.
> *
> * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
> * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
> * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
> * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
> * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
> * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
> * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
> * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
> * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
> * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
> * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> * SUCH DAMAGE.
> * ====================================================================
> *
> * This software consists of voluntary contributions made by many
> * individuals on behalf of the Apache Software Foundation. For more
> * information on the Apache Software Foundation, please see
> * <http://www.apache.org/>.
> */
> import java.io.InputStream;
> import java.io.StringReader;
> import java.io.BufferedInputStream;
> import java.sql.*;
> import javax.sql.DataSource;
> import javax.naming.InitialContext;
> import java.util.Map;
> import java.util.Hashtable;
> import org.apache.velocity.util.StringUtils;
> import org.apache.velocity.runtime.Runtime;
> import org.apache.velocity.runtime.resource.Resource;
> /**
> * This is a simple template file loader that loads templates
> * from a DataSource instead of plain files.
> *
> * It can be configured with a datasource name, a table name,
> * id column (name), content column (the template body) and a
> * timestamp column (for last modification info).
> *
> * @author <a href="mailto:[EMAIL PROTECTED]">David Kinnvall</a>
> */
> public class DBResourceLoader extends ResourceLoader
> {
> private String dataSourceName;
> private String tableName;
> private String keyColumn;
> private String templateColumn;
> private String timestampColumn;
> private InitialContext ctx;
> private DataSource dataSource;
>
> /*
> * This should probably be moved into the super class,
> * the stand init stuff. For the properties that all
> * loaders will probably share.
> */
> public void init(Map initializer)
> {
> dataSourceName = (String) initializer.get("resource.datasource");
> tableName = (String) initializer.get("resource.table");
> keyColumn = (String) initializer.get("resource.keycolumn");
> templateColumn = (String) initializer.get("resource.templatecolumn");
> timestampColumn = (String)
> initializer.get("resource.timestampcolumn");
> Runtime.info("Resources Loaded From: " + dataSourceName + "/" +
> tableName);
> Runtime.info("Resource Loader using columns: " + keyColumn + ", "
> + templateColumn + " and " + timestampColumn);
> Runtime.info("Resource Loader Initalized.");
> }
> /**
> * Get an InputStream so that the Runtime can build a
> * template with it.
> */
> public synchronized InputStream getResourceStream( String name )
> throws Exception
> {
> if (name == null || name.length() == 0)
> {
> throw new Exception ("Need to specify a template name!");
> }
> Connection conn = null;
> try {
> if(ctx == null) ctx = new InitialContext();
> if(dataSource == null) dataSource =
> (DataSource)ctx.lookup(dataSourceName);
> conn = dataSource.getConnection();
> Statement stmt = conn.createStatement();
> String query = "select " + templateColumn
> + " from " + tableName
> + " where " + keyColumn + " = '" + name + "'";
> ResultSet rs = stmt.executeQuery(query);
> if(rs.next())
> {
> return new
> BufferedInputStream(rs.getAsciiStream(templateColumn));
> }
> else
> {
> Runtime.error("DBResourceLoader Error: cannot find
> resource " + name);
> }
> } catch (Exception e) {
> Runtime.error("DBResourceLoader Error: database problem trying
> to load resource " + name + ": " + e.toString());
> } finally {
> try {
> conn.close();
> } catch (Exception e) {
> Runtime.info("DBResourceLoader Quirk: problem when closing
> connection: " + e.toString());
> }
> }
>
> return null;
> }
> public boolean isSourceModified(Resource resource)
> {
> String name = resource.getName();
>
> Connection conn = null;
> try {
> if(ctx == null) ctx = new InitialContext();
> if(dataSource == null) dataSource =
> (DataSource)ctx.lookup(dataSourceName);
> conn = dataSource.getConnection();
> Statement stmt = conn.createStatement();
> String query = "select " + timestampColumn
> + " from " + tableName
> + " where " + keyColumn + " = '" + name + "'";
> ResultSet rs = stmt.executeQuery(query);
> if(rs.next())
> {
> long lastModified = rs.getLong(timestampColumn);
> if (lastModified != resource.getLastModified())
> return true;
> else
> return false;
> }
> else
> {
> Runtime.info("DBResourceLoader Error: cannot check
> timestamp on resource " + name);
> }
> } catch (Exception e) {
> Runtime.info("DBResourceLoader Error: database problem
> checking timestamp on resource " + name + ": " + e.toString());
> } finally {
> try {
> conn.close();
> } catch (Exception e) {
> Runtime.info("DBResourceLoader Quirk: problem when closing
> connection: " + e.toString());
> }
> }
>
> return true;
> }
> public long getLastModified(Resource resource)
> {
> String name = resource.getName();
>
> Connection conn = null;
> try {
> if(ctx == null) ctx = new InitialContext();
> if(dataSource == null) dataSource =
> (DataSource)ctx.lookup(dataSourceName);
> conn = dataSource.getConnection();
> Statement stmt = conn.createStatement();
> String query = "select " + timestampColumn
> + " from " + tableName
> + " where " + keyColumn + " = '" + name + "'";
> ResultSet rs = stmt.executeQuery(query);
> if(rs.next())
> {
> return rs.getLong(timestampColumn);
> }
> else
> {
> Runtime.info("DBResourceLoader Error: cannot get timestamp
> on resource " + name);
> }
> } catch (Exception e) {
> Runtime.info("DBResourceLoader Error: database problem getting
> timestamp on resource " + name + ": " + e.toString());
> } finally {
> try {
> conn.close();
> } catch (Exception e) {
> Runtime.info("DBResourceLoader Quirk: problem when closing
> connection: " + e.toString());
> }
> }
>
> return 0;
> }
> }
>
> --
> David Kinnvall
> Alert Investor Relations AB
> +46 31 802640/10, +46 31 802670 (fax), +46 705 818432 (mobile)
--
Geir Magnusson Jr. [EMAIL PROTECTED]
Velocity : it's not just a good idea. It should be the law.
http://jakarta.apache.org/velocity
