/*
 *  Copyright 2008 biaoping.yin
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.frameworkset.util;

import java.io.File;
import java.io.FileNotFoundException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;

import com.frameworkset.util.SimpleStringUtil;

/**
 * <p>
 * Title: ResourceUtils.java
 * </p>
 * <p>
 * Description:
 * </p>
 * <p>
 * bboss workgroup
 * </p>
 * <p>
 * Copyright (c) 2008
 * </p>
 * 
 * @Date 2010-9-24
 * @author biaoping.yin
 * @version 1.0
 */
public class ResourceUtils
{

	/** Pseudo URL prefix for loading from the class path: "classpath:" */
	public static final String	CLASSPATH_URL_PREFIX		= "classpath:";

	/** URL prefix for loading from the file system: "file:" */
	public static final String	FILE_URL_PREFIX				= "file:";

	/** URL protocol for a file in the file system: "file" */
	public static final String	URL_PROTOCOL_FILE			= "file";

	/** URL protocol for an entry from a jar file: "jar" */
	public static final String	URL_PROTOCOL_JAR			= "jar";

	/** URL protocol for an entry from a zip file: "zip" */
	public static final String	URL_PROTOCOL_ZIP			= "zip";

	/** URL protocol for an entry from a JBoss jar file: "vfszip" */
	public static final String	URL_PROTOCOL_VFSZIP			= "vfszip";

	/** URL protocol for an entry from a WebSphere jar file: "wsjar" */
	public static final String	URL_PROTOCOL_WSJAR			= "wsjar";

	/** URL protocol for an entry from an OC4J jar file: "code-source" */
	public static final String	URL_PROTOCOL_CODE_SOURCE	= "code-source";

	/** Separator between JAR URL and file path within the JAR */
	public static final String	JAR_URL_SEPARATOR			= "!/";

	/**
	 * Return whether the given resource location is a URL: either a special
	 * "classpath" pseudo URL or a standard URL.
	 * 
	 * @param resourceLocation
	 *            the location String to check
	 * @return whether the location qualifies as a URL
	 * @see #CLASSPATH_URL_PREFIX
	 * @see java.net.URL
	 */
	public static boolean isUrl(String resourceLocation)
	{

		if (resourceLocation == null)
		{
			return false;
		}
		if (resourceLocation.startsWith(CLASSPATH_URL_PREFIX))
		{
			return true;
		}
		try
		{
			new URL(resourceLocation);
			return true;
		}
		catch (MalformedURLException ex)
		{
			return false;
		}
	}

	/**
	 * Resolve the given resource location to a <code>java.net.URL</code>.
	 * <p>
	 * Does not check whether the URL actually exists; simply returns the URL
	 * that the given location would correspond to.
	 * 
	 * @param resourceLocation
	 *            the resource location to resolve: either a "classpath:" pseudo
	 *            URL, a "file:" URL, or a plain file path
	 * @return a corresponding URL object
	 * @throws FileNotFoundException
	 *             if the resource cannot be resolved to a URL
	 */
	public static URL getURL(String resourceLocation)
			throws FileNotFoundException
	{

		Assert.notNull(resourceLocation, "Resource location must not be null");
		if (resourceLocation.startsWith(CLASSPATH_URL_PREFIX))
		{
			String path = resourceLocation.substring(CLASSPATH_URL_PREFIX
					.length());
			URL url = ClassUtils.getDefaultClassLoader().getResource(path);
			if (url == null)
			{
				String description = "class path resource [" + path + "]";
				throw new FileNotFoundException(
						description
								+ " cannot be resolved to URL because it does not exist");
			}
			return url;
		}
		try
		{
			// try URL
			return new URL(resourceLocation);
		}
		catch (MalformedURLException ex)
		{
			// no URL -> treat as file path
			try
			{
				return new File(resourceLocation).toURI().toURL();
			}
			catch (MalformedURLException ex2)
			{
				throw new FileNotFoundException("Resource location ["
						+ resourceLocation
						+ "] is neither a URL not a well-formed file path");
			}
		}
	}

	/**
	 * Resolve the given resource location to a <code>java.io.File</code>, i.e.
	 * to a file in the file system.
	 * <p>
	 * Does not check whether the fil actually exists; simply returns the File
	 * that the given location would correspond to.
	 * 
	 * @param resourceLocation
	 *            the resource location to resolve: either a "classpath:" pseudo
	 *            URL, a "file:" URL, or a plain file path
	 * @return a corresponding File object
	 * @throws FileNotFoundException
	 *             if the resource cannot be resolved to a file in the file
	 *             system
	 */
	public static File getFile(String resourceLocation)
			throws FileNotFoundException
	{

		Assert.notNull(resourceLocation, "Resource location must not be null");
		if (resourceLocation.startsWith(CLASSPATH_URL_PREFIX))
		{
			String path = resourceLocation.substring(CLASSPATH_URL_PREFIX
					.length());
			String description = "class path resource [" + path + "]";
			URL url = ClassUtils.getDefaultClassLoader().getResource(path);
			if (url == null)
			{
				throw new FileNotFoundException(description
						+ " cannot be resolved to absolute file path "
						+ "because it does not reside in the file system");
			}
			return getFile(url, description);
		}
		try
		{
			// try URL
			return getFile(new URL(resourceLocation));
		}
		catch (MalformedURLException ex)
		{
			// no URL -> treat as file path
			return new File(resourceLocation);
		}
	}

	private static ClassLoader getTCL()
	{

		Method method = null;
		try
		{
			method = (java.lang.Thread.class)
					.getMethod("getContextClassLoader", null);
		}
		catch (NoSuchMethodException e)
		{
			return null;
		}
		try
		{
			return (ClassLoader) method.invoke(Thread.currentThread(), null);
		}
		catch (IllegalArgumentException e)
		{
			// TODO Auto-generated catch block
			e.printStackTrace();
			return null;
		}
		catch (IllegalAccessException e)
		{
			// TODO Auto-generated catch block
			e.printStackTrace();
			return null;
		}
		catch (InvocationTargetException e)
		{
			// TODO Auto-generated catch block
			e.printStackTrace();
			return null;
		}
	}

	public static URL getFileURL(String file)
	{

		URL confURL = ResourceUtils.class.getClassLoader().getResource(file);
		if (confURL == null)
			confURL = ResourceUtils.class.getClassLoader()
					.getResource("/" + file);

		if (confURL == null)
			confURL = getTCL().getResource(file);
		if (confURL == null)
			confURL = getTCL().getResource("/" + file);
		if (confURL == null)
			confURL = ClassLoader.getSystemResource(file);
		if (confURL == null)
			confURL = ClassLoader.getSystemResource("/" + file);

		if (confURL == null)
		{
			throw new java.lang.NullPointerException(file + " do not exist.");
		}
		else
		{
			return confURL;
		}

	}

	/**
	 * Resolve the given resource URL to a <code>java.io.File</code>, i.e. to a
	 * file in the file system.
	 * 
	 * @param resourceUrl
	 *            the resource URL to resolve
	 * @return a corresponding File object
	 * @throws FileNotFoundException
	 *             if the URL cannot be resolved to a file in the file system
	 */
	public static File getFile(URL resourceUrl) throws FileNotFoundException
	{

		return getFile(resourceUrl, "URL");
	}

	/**
	 * Resolve the given resource URL to a <code>java.io.File</code>, i.e. to a
	 * file in the file system.
	 * 
	 * @param resourceUrl
	 *            the resource URL to resolve
	 * @param description
	 *            a description of the original resource that the URL was
	 *            created for (for example, a class path location)
	 * @return a corresponding File object
	 * @throws FileNotFoundException
	 *             if the URL cannot be resolved to a file in the file system
	 */
	public static File getFile(URL resourceUrl, String description)
			throws FileNotFoundException
	{

		Assert.notNull(resourceUrl, "Resource URL must not be null");
		if (!URL_PROTOCOL_FILE.equals(resourceUrl.getProtocol()))
		{
			throw new FileNotFoundException(description
					+ " cannot be resolved to absolute file path "
					+ "because it does not reside in the file system: "
					+ resourceUrl);
		}
		try
		{
			return new File(toURI(resourceUrl).getSchemeSpecificPart());
		}
		catch (URISyntaxException ex)
		{
			// Fallback for URLs that are not valid URIs (should hardly ever
			// happen).
			return new File(resourceUrl.getFile());
		}
	}

	/**
	 * Resolve the given resource URI to a <code>java.io.File</code>, i.e. to a
	 * file in the file system.
	 * 
	 * @param resourceUri
	 *            the resource URI to resolve
	 * @return a corresponding File object
	 * @throws FileNotFoundException
	 *             if the URL cannot be resolved to a file in the file system
	 */
	public static File getFile(URI resourceUri) throws FileNotFoundException
	{

		return getFile(resourceUri, "URI");
	}

	/**
	 * Resolve the given resource URI to a <code>java.io.File</code>, i.e. to a
	 * file in the file system.
	 * 
	 * @param resourceUri
	 *            the resource URI to resolve
	 * @param description
	 *            a description of the original resource that the URI was
	 *            created for (for example, a class path location)
	 * @return a corresponding File object
	 * @throws FileNotFoundException
	 *             if the URL cannot be resolved to a file in the file system
	 */
	public static File getFile(URI resourceUri, String description)
			throws FileNotFoundException
	{

		Assert.notNull(resourceUri, "Resource URI must not be null");
		if (!URL_PROTOCOL_FILE.equals(resourceUri.getScheme()))
		{
			throw new FileNotFoundException(description
					+ " cannot be resolved to absolute file path "
					+ "because it does not reside in the file system: "
					+ resourceUri);
		}
		return new File(resourceUri.getSchemeSpecificPart());
	}

	/**
	 * Determine whether the given URL points to a resource in a jar file, that
	 * is, has protocol "jar", "zip", "wsjar" or "code-source".
	 * <p>
	 * "zip" and "wsjar" are used by BEA WebLogic Server and IBM WebSphere,
	 * respectively, but can be treated like jar files. The same applies to
	 * "code-source" URLs on Oracle OC4J, provided that the path contains a jar
	 * separator.
	 * 
	 * @param url
	 *            the URL to check
	 * @return whether the URL has been identified as a JAR URL
	 */
	public static boolean isJarURL(URL url)
	{

		String protocol = url.getProtocol();
		return (URL_PROTOCOL_JAR.equals(protocol)
				|| URL_PROTOCOL_ZIP.equals(protocol)
				|| URL_PROTOCOL_VFSZIP.equals(protocol)
				|| URL_PROTOCOL_WSJAR.equals(protocol) || (URL_PROTOCOL_CODE_SOURCE
				.equals(protocol) && url.getPath().indexOf(JAR_URL_SEPARATOR) != -1));
	}

	/**
	 * Extract the URL for the actual jar file from the given URL (which may
	 * point to a resource in a jar file or to a jar file itself).
	 * 
	 * @param jarUrl
	 *            the original URL
	 * @return the URL for the actual jar file
	 * @throws MalformedURLException
	 *             if no valid jar file URL could be extracted
	 */
	public static URL extractJarFileURL(URL jarUrl)
			throws MalformedURLException
	{

		String urlFile = jarUrl.getFile();
		int separatorIndex = urlFile.indexOf(JAR_URL_SEPARATOR);
		if (separatorIndex != -1)
		{
			String jarFile = urlFile.substring(0, separatorIndex);
			try
			{
				return new URL(jarFile);
			}
			catch (MalformedURLException ex)
			{
				// Probably no protocol in original jar URL, like
				// "jar:C:/mypath/myjar.jar".
				// This usually indicates that the jar file resides in the file
				// system.
				if (!jarFile.startsWith("/"))
				{
					jarFile = "/" + jarFile;
				}
				return new URL(FILE_URL_PREFIX + jarFile);
			}
		}
		else
		{
			return jarUrl;
		}
	}

	/**
	 * Create a URI instance for the given URL, replacing spaces with "%20"
	 * quotes first.
	 * <p>
	 * Furthermore, this method works on JDK 1.4 as well, in contrast to the
	 * <code>URL.toURI()</code> method.
	 * 
	 * @param url
	 *            the URL to convert into a URI instance
	 * @return the URI instance
	 * @throws URISyntaxException
	 *             if the URL wasn't a valid URI
	 * @see java.net.URL#toURI()
	 */
	public static URI toURI(URL url) throws URISyntaxException
	{

		return toURI(url.toString());
	}

	/**
	 * Create a URI instance for the given location String, replacing spaces
	 * with "%20" quotes first.
	 * 
	 * @param location
	 *            the location String to convert into a URI instance
	 * @return the URI instance
	 * @throws URISyntaxException
	 *             if the location wasn't a valid URI
	 */
	public static URI toURI(String location) throws URISyntaxException
	{

		return new URI(SimpleStringUtil.replace(location, " ", "%20"));
	}

}
