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Hibernate example source code file (ConfigHelper.java)

This example Hibernate source code file (ConfigHelper.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Hibernate tags/keywords

classloader, confighelper, coremessagelogger, hibernateexception, hibernateexception, inputstream, inputstream, io, net, network, properties, reader, string, string, unable, url, url, util

The Hibernate ConfigHelper.java source code

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008-2011, Red Hat Inc. or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Inc.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */
package org.hibernate.internal.util;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Properties;
import org.hibernate.HibernateException;
import org.hibernate.internal.CoreMessageLogger;
import org.hibernate.cfg.Environment;

import org.jboss.logging.Logger;

/**
 * A simple class to centralize logic needed to locate config files on the system.
 *
 * @todo : Update usages to use {@link org.hibernate.service.classloading.spi.ClassLoaderService}
 *
 * @author Steve Ebersole
 */
public final class ConfigHelper {

    private static final CoreMessageLogger LOG = Logger.getMessageLogger(CoreMessageLogger.class, ConfigHelper.class.getName());

	/** Try to locate a local URL representing the incoming path.  The first attempt
	 * assumes that the incoming path is an actual URL string (file://, etc).  If this
	 * does not work, then the next attempts try to locate this UURL as a java system
	 * resource.
	 *
	 * @param path The path representing the config location.
	 * @return An appropriate URL or null.
	 */
	public static URL locateConfig(final String path) {
		try {
			return new URL(path);
		}
		catch(MalformedURLException e) {
			return findAsResource(path);
		}
	}

	/**
	 * Try to locate a local URL representing the incoming path.
	 * This method <b>only attempts to locate this URL as a
	 * java system resource.
	 *
	 * @param path The path representing the config location.
	 * @return An appropriate URL or null.
	 */
	public static URL findAsResource(final String path) {
		URL url = null;

		// First, try to locate this resource through the current
		// context classloader.
		ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
		if (contextClassLoader!=null) {
			url = contextClassLoader.getResource(path);
		}
		if (url != null)
			return url;

		// Next, try to locate this resource through this class's classloader
		url = ConfigHelper.class.getClassLoader().getResource(path);
		if (url != null)
			return url;

		// Next, try to locate this resource through the system classloader
		url = ClassLoader.getSystemClassLoader().getResource(path);

		// Anywhere else we should look?
		return url;
	}

	/** Open an InputStream to the URL represented by the incoming path.  First makes a call
	 * to {@link #locateConfig(java.lang.String)} in order to find an appropriate URL.
	 * {@link java.net.URL#openStream()} is then called to obtain the stream.
	 *
	 * @param path The path representing the config location.
	 * @return An input stream to the requested config resource.
	 * @throws HibernateException Unable to open stream to that resource.
	 */
	public static InputStream getConfigStream(final String path) throws HibernateException {
		final URL url = ConfigHelper.locateConfig(path);

		if (url == null) {
            String msg = LOG.unableToLocateConfigFile(path);
            LOG.error(msg);
			throw new HibernateException(msg);
		}

		try {
			return url.openStream();
        }
		catch(IOException e) {
	        throw new HibernateException("Unable to open config file: " + path, e);
        }
	}

	/** Open an Reader to the URL represented by the incoming path.  First makes a call
	 * to {@link #locateConfig(java.lang.String)} in order to find an appropriate URL.
	 * {@link java.net.URL#openStream()} is then called to obtain a stream, which is then
	 * wrapped in a Reader.
	 *
	 * @param path The path representing the config location.
	 * @return An input stream to the requested config resource.
	 * @throws HibernateException Unable to open reader to that resource.
	 */
	public static Reader getConfigStreamReader(final String path) throws HibernateException {
		return new InputStreamReader( getConfigStream(path) );
	}

	/** Loads a properties instance based on the data at the incoming config location.
	 *
	 * @param path The path representing the config location.
	 * @return The loaded properties instance.
	 * @throws HibernateException Unable to load properties from that resource.
	 */
	public static Properties getConfigProperties(String path) throws HibernateException {
		try {
			Properties properties = new Properties();
			properties.load( getConfigStream(path) );
			return properties;
		}
		catch(IOException e) {
			throw new HibernateException("Unable to load properties from specified config file: " + path, e);
		}
	}

	private ConfigHelper() {}

	public static InputStream getResourceAsStream(String resource) {
		String stripped = resource.startsWith("/") ?
				resource.substring(1) : resource;

		InputStream stream = null;
		ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
		if (classLoader!=null) {
			stream = classLoader.getResourceAsStream( stripped );
		}
		if ( stream == null ) {
			stream = Environment.class.getResourceAsStream( resource );
		}
		if ( stream == null ) {
			stream = Environment.class.getClassLoader().getResourceAsStream( stripped );
		}
		if ( stream == null ) {
			throw new HibernateException( resource + " not found" );
		}
		return stream;
	}


	public static InputStream getUserResourceAsStream(String resource) {
		boolean hasLeadingSlash = resource.startsWith( "/" );
		String stripped = hasLeadingSlash ? resource.substring(1) : resource;

		InputStream stream = null;

		ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
		if ( classLoader != null ) {
			stream = classLoader.getResourceAsStream( resource );
			if ( stream == null && hasLeadingSlash ) {
				stream = classLoader.getResourceAsStream( stripped );
			}
		}

		if ( stream == null ) {
			stream = Environment.class.getClassLoader().getResourceAsStream( resource );
		}
		if ( stream == null && hasLeadingSlash ) {
			stream = Environment.class.getClassLoader().getResourceAsStream( stripped );
		}

		if ( stream == null ) {
			throw new HibernateException( resource + " not found" );
		}

		return stream;
	}
}

Other Hibernate examples (source code examples)

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