package org.apache.fulcrum.yaafi.framework.util;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.
   */
  
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  
  import org.apache.avalon.framework.logger.Logger;
  import org.apache.avalon.framework.logger.NullLogger;
  
  /**
   * Helper for locating a file name and returning an input stream.
   *
   * @author <a href="mailto:siegfried.goeschl@it20one.at">Siegfried Goeschl</a>
   */
  
  public class InputStreamLocator {
  	
  	/** the root directory of our search */
  	private File rootDir;
  
  	/** the logger to be used */
  	private Logger logger;
  
  	/**
  	 * Constructor
  	 */
  	public InputStreamLocator() {
  		this.rootDir = new File(new File("").getAbsolutePath());
  		this.logger = new NullLogger();
  	}
  
  	/**
  	 * Constructor
  	 *
  	 * @param rootDir the root directory to start the search
  	 */
  	public InputStreamLocator(File rootDir) {
  		this(rootDir, new NullLogger());
  	}
  
  	/**
  	 * Constructor
  	 *
  	 * @param rootDir the root directory to start the search
  	 * @param logger  the logger to be used
  	 */
  	public InputStreamLocator(File rootDir, Logger logger) {
  		this.rootDir = rootDir;
  		this.logger = logger;
  	}
  
  	/**
  	 * Locate the file with the given position using the following steps
  	 *
  	 * @param location the location of the source to be loaded
  	 * @return input stream of the source
  	 * @throws IOException if source is not found
  	 */
  	public InputStream locate(String location) throws IOException {
  		if (location == null || location.length() == 0) {
  			return null;
  		}
  
  		String baseName = null;
  		File file = null;
  		InputStream is = null;
  
  		// try to load a relative location with the given root dir
  		// e.g. "componentRoles.xml" located in the current working directory
  		if (is == null) {
  			file = new File(this.rootDir, location);
  
  			this.logger.debug("Looking for " + location + " in the root directory");
  
  			if (file.exists()) {
  				is = new FileInputStream(file);
  				this.logger.debug("Found " + location + " as " + file.getAbsolutePath());
  			}
  		}
 
 		// try to load an absolute location as file
 		// e.g. "/foo/componentRoles.xml" from the root of the file system
 		if (is == null) {
 			file = new File(location);
 
 			this.logger.debug("Looking for " + location + " as absolute file location");
 
 			if (file.isAbsolute() && file.exists()) {
 				is = new FileInputStream(file);
 				this.logger.debug("Found " + location + " as " + file.getAbsolutePath());
 			}
 		}
 
 		// try to load an absolute location through the classpath
 		// e.g. "/componentRoles.xml" located in the classpath
 		if (is == null && location.startsWith("/") == true) {
 			this.logger.debug("Looking for " + location + " using the class loader");
 			is = getClass().getResourceAsStream(location);
 
 			if (is != null) {
 				this.logger.debug("Successfully located " + location);
 			}
 		}
 
 		// try to load the last part of the file name using the classloader
 		// e.g. "conf/componentRoles.xml" as "/componentRoles.xml" located in
 		// the classpath.
 
 		if (is == null && location.startsWith("/") == false) {
 			baseName = '/' + new File(location).getName();
 			this.logger.debug("Looking for " + baseName + " using the class loader");
 			is = getClass().getResourceAsStream(baseName);
 			if (is != null) {
 				this.logger.debug("Successfully located " + baseName);
 			}
 		}
 
 		if (is == null) {
 			this.logger.debug("Unable to find any resource with the name '" + location + "'");
 		}
 
 		return is;
 	}
 
 	/**
 	 * @return Returns the rootDir.
 	 */
 	protected File getRootDir() {
 		return rootDir;
 	}
 
 }