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/* ====================================================================
 * 
 * The ObjectStyle Group Software License, version 1.1
 * ObjectStyle Group - http://objectstyle.org/
 * 
 * Copyright (c) 2002-2005, Andrei (Andrus) Adamchik and individual authors
 * of the software. 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 independent contributors
 *    and hosted on ObjectStyle Group web site (http://objectstyle.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 * 
 * 4. The names "ObjectStyle Group" and "Cayenne" must not be used to endorse
 *    or promote products derived from this software without prior written
 *    permission. For written permission, email
 *    "andrus at objectstyle dot org".
 * 
 * 5. Products derived from this software may not be called "ObjectStyle"
 *    or "Cayenne", nor may "ObjectStyle" or "Cayenne" appear in their
 *    names without prior written permission.
 * 
 * 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 OBJECTSTYLE GROUP 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 and hosted on ObjectStyle Group web site.  For more
 * information on the ObjectStyle Group, please see
 * .
 */
package org.objectstyle.cayenne.project;

import java.io.File;

import org.apache.log4j.Logger;

/**
 * CayenneUserDir represents a directory where all Cayenne-related information 
 * is stored on the user machine. This is normally a $HOME/.cayenne
 * directory.
 * 
 * @author Andrei Adamchik
 */
public class CayenneUserDir {
	static final Logger logObj = Logger.getLogger(CayenneUserDir.class);
	
    protected static CayenneUserDir sharedInstance;

    public static final String CAYENNE_DIR = ".cayenne";
    
    /**
     * A property name for the property that allows to define an alternative
     * location of Cayenne User Directory (instead of default "$HOME/.cayenne").
     *  
     * @since 1.1
     */
    public static final String ALT_USER_DIR_PROPERTY = "cayenne.userdir";

    protected File cayenneUserDir;

    public static CayenneUserDir getInstance() {
    	if(sharedInstance == null) {
    		sharedInstance = new CayenneUserDir();
    	}
    	return sharedInstance;
    }
    
    
    /**
     * Constructor for CayenneUserDir.
     */
    protected CayenneUserDir() {
        super();

        File tmpDir = null;
        String dirName = System.getProperty(ALT_USER_DIR_PROPERTY);

        if (dirName != null) {
            tmpDir = new File(dirName);
        }
        else {
            File homeDir = new File(System.getProperty("user.home"));
            tmpDir = new File(homeDir, CAYENNE_DIR);
        }

        if (tmpDir.exists() && !tmpDir.isDirectory()) {
            tmpDir = null;
            logObj.warn(tmpDir + " is not a directory.");
        }
        else if (tmpDir.exists() && !tmpDir.canRead()) {
            tmpDir = null;
            logObj.warn(tmpDir + " is not readable.");
        }
        else if (!tmpDir.exists()) {
            tmpDir.mkdirs();
            if (!tmpDir.exists()) {
                tmpDir = null;
                logObj.warn("Couldn't create " + tmpDir);
            }
        }

        cayenneUserDir = tmpDir;
    }

    /**
     * Returns a directory object where all user Cayenne-related configuration is stored.
     * May return null if the directory is not accessible for whatever reason.
     */
    public File getDirectory() {
        return cayenneUserDir;
    }
    
    /**
     * Return false if the directory is not accessible for
     * any reason at least for reading.
     */    
    public boolean canRead() {
    	return cayenneUserDir != null;
    }
    
    /**
     * Return false if the directory is not accessible for
     * any reason at least for reading.
     */    
    public boolean canWrite() {
    	return cayenneUserDir != null && cayenneUserDir.canWrite();
    }
    
    public File resolveFile(String name) {
    	return new File(cayenneUserDir, name);
    }
}