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 *   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.
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package org.apache.cayenne.conf;

import java.io.File;

import org.apache.cayenne.ConfigurationException;
import org.apache.cayenne.util.ResourceLocator;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * FileConfiguration loads a Cayenne configuraton file from a given
 * location in the file system.
 *
 * @author Holger Hoffstaette
 */
public class FileConfiguration extends DefaultConfiguration {
    private static final Log logger = LogFactory.getLog(FileConfiguration.class);

	/**
	 * The domain file used for this configuration
	 */
	protected File projectFile;

	/**
	 * Default constructor.
	 * Simply calls {@link FileConfiguration#FileConfiguration(String)}
	 * with {@link Configuration#DEFAULT_DOMAIN_FILE} as argument.
	 * @see DefaultConfiguration#DefaultConfiguration()
	 */
	public FileConfiguration() {
		this(Configuration.DEFAULT_DOMAIN_FILE);
	}

	/**
	 * Creates a configuration that uses the provided file name
	 * as the main project file, ignoring any other lookup strategies.
	 * The file name is <b>not</b> checked for existence and must not
	 * contain relative or absolute paths, i.e. only the file name.
	 *
	 * @throws ConfigurationException when projectFile is <code>null</code>.
	 * @see DefaultConfiguration#DefaultConfiguration(String)
	 */
	public FileConfiguration(String domainConfigurationName) {
		super(domainConfigurationName);

		// set the project file
		this.projectFile = new File(domainConfigurationName);

		// configure the ResourceLocator for plain files
		ResourceLocator locator = this.getResourceLocator();
		locator.setSkipAbsolutePath(false);
		locator.setSkipClasspath(true);
		locator.setSkipCurrentDirectory(false);
		locator.setSkipHomeDirectory(true);

		// add the file's location to the search path, if it exists
		File projectDirectory = this.getProjectDirectory();
		if (projectDirectory != null) {
			locator.addFilesystemPath(projectDirectory.getPath());
		}
	}

	/**
	 * Creates a configuration that uses the provided file 
	 * as the main project file, ignoring any other lookup strategies.
	 * 
	 * @throws ConfigurationException when projectFile is <code>null</code>,
	 * a directory or not readable.
	 */
	public FileConfiguration(File domainConfigurationFile) {
		super();

		logger.debug("using domain file: " + domainConfigurationFile);

		// set the project file
		this.setProjectFile(domainConfigurationFile);

		// configure the ResourceLocator for plain files
		ResourceLocator locator = this.getResourceLocator();
		locator.setSkipAbsolutePath(false);
		locator.setSkipClasspath(true);
		locator.setSkipCurrentDirectory(false);
		locator.setSkipHomeDirectory(true);

		// add the file's location to the search path, if it exists
		File projectDirectory = this.getProjectDirectory();
		if (projectDirectory != null) {
			locator.addFilesystemPath(projectDirectory);
		}
	}

	/**
	 * Adds the given String as a custom path for filesystem lookups.
	 * The path can be relative or absolute and is <i>not</i> checked
	 * for existence.
	 *
	 * This allows for easy customization of resource search paths after
	 * Constructor invocation:
	 * <pre>
	 * conf = new FileConfiguration("myconfig-cayenne.xml");
	 * conf.addFilesystemPath(new File("a/relative/path"));
	 * conf.addFilesystemPath(new File("/an/absolute/search/path"));
	 * Configuration.initializeSharedConfiguration(conf);
	 * </pre>
	 * 
	 * Alternatively use {@link FileConfiguration#addFilesystemPath(File)}
	 * for adding a path that is checked for existence.
	 * 
	 * @throws IllegalArgumentException if <code>path</code> is <code>null</code>.
	 */
	public void addFilesystemPath(String path) {
		this.getResourceLocator().addFilesystemPath(path);
	}

	/**
	 * Adds the given directory as a path for filesystem lookups.
	 * The directory is checked for existence.
	 * 
	 * @throws IllegalArgumentException if <code>path</code> is <code>null</code>,
	 * not a directory or not readable.
	 */
	public void addFilesystemPath(File path) {
		this.getResourceLocator().addFilesystemPath(path);
	}

	/**
	 * Only returns <code>true</code> when {@link #getProjectFile} does not
	 * return <code>null</code>.
	 */
	@Override
    public boolean canInitialize() {
		// I can only initialize myself when I have a valid file
		return (this.getProjectFile() != null);
	}

	/**
	 * Returns the main domain file used for this configuration. 
	 */
	public File getProjectFile() {
		return projectFile;
	}

	/**
	 * Sets the main domain file used for this configuration.
	 * @throws ConfigurationException if <code>projectFile</code> is null,
	 * a directory or not readable.
	 */
	protected void setProjectFile(File projectFile) {
		if (projectFile != null) {
			if (projectFile.isFile()) {
				this.projectFile = projectFile;
				this.setDomainConfigurationName(projectFile.getName());
			}
			else {
				throw new ConfigurationException("Project file: "
													+ projectFile
													+ " is a directory or not readable.");
			}
		}
		else {
			throw new ConfigurationException("Cannot use null as project file.");
		}
	}

	/**
	 * Returns the directory of the current project file as
	 * returned by {@link #getProjectFile}.
	 */
	public File getProjectDirectory() {
		File pfile = this.getProjectFile();
		if (pfile != null) {
			return pfile.getParentFile();
		}
		else {
			return null;
		}
	}
}
