content: /* ========================================================================
   * JCommon : a free general purpose class library for the Java(tm) platform
   * ========================================================================
   *
   * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
   * 
   * Project Info:  http://www.jfree.org/jcommon/index.html
   *
   * This library is free software; you can redistribute it and/or modify it 
   * under the terms of the GNU Lesser General Public License as published by 
   * the Free Software Foundation; either version 2.1 of the License, or 
   * (at your option) any later version.
   *
   * This library 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 library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
   * USA.  
   *
   * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
   * in the United States and other countries.]
   * 
   * -----------------
   * PackageState.java
   * -----------------
   * (C)opyright 2003, 2004, by Thomas Morgner and Contributors.
   *
   * Original Author:  Thomas Morgner;
   * Contributor(s):   David Gilbert (for Object Refinery Limited);
   *
   * $Id: PackageState.java,v 1.4 2006/04/14 13:00:56 taqua Exp $
   *
   * Changes
   * -------
   * 10-Jul-2003 : Initial version
   * 07-Jun-2004 : Added JCommon header (DG);
   * 
   */
  
  package org.jfree.base.modules;
  
  import org.jfree.util.Log;
  
  /**
   * The package state class is used by the package manager to keep track of
   * the activation level of the installed or errornous packages.
   *
   * @author Thomas Morgner
   */
  public class PackageState
  {
    /** A constant defining that the package is new. */
    public static final int STATE_NEW = 0;
    
    /** A constant defining that the package has been loaded and configured. */
    public static final int STATE_CONFIGURED = 1;
    
    /** A constant defining that the package was initialized and is ready to use. */
    public static final int STATE_INITIALIZED = 2;
    
    /** A constant defining that the package produced an error and is not available. */
    public static final int STATE_ERROR = -2;
  
    /** The module class that contains the package information. */
    private final Module module;
    /** The state of the module. */
    private int state;
  
    /**
     * Creates a new package state for the given module. The module state will
     * be initialized to STATE_NEW.
     *
     * @param module the module.
     */
    public PackageState(final Module module)
    {
      this (module, STATE_NEW);
    }
  
    /**
     * Creates a new package state for the given module. The module state will
     * be initialized to the given initial state.
     *
     * @param module the module.
     * @param state the initial state
     */
    public PackageState(final Module module, final int state)
    {
      if (module == null)
      {
        throw new NullPointerException("Module must not be null.");
      }
      if (state != STATE_CONFIGURED && state != STATE_ERROR 
              && state != STATE_INITIALIZED && state != STATE_NEW)
      {
        throw new IllegalArgumentException("State is not valid");
      }
      this.module = module;
      this.state = state;
    }
  
    /**
     * Configures the module and raises the state to STATE_CONFIGURED if the
     * module is not yet configured.
     *
     * @param subSystem  the sub-system.
     * 
     * @return true, if the module was configured, false otherwise.
     */
    public boolean configure(final SubSystem subSystem)
    {
      if (this.state == STATE_NEW)
      {
        try
        {
          this.module.configure(subSystem);
          this.state = STATE_CONFIGURED;
          return true;
        }
        catch (NoClassDefFoundError noClassDef)
        {
          Log.warn (new Log.SimpleMessage("Unable to load module classes for ",
                  this.module.getName(), ":", noClassDef.getMessage()));
          this.state = STATE_ERROR;
        }
        catch (Exception e)
        {
          if (Log.isDebugEnabled())
          {
            // its still worth a warning, but now we are more verbose ...
            Log.warn("Unable to configure the module " + this.module.getName(), e);
          }
          else if (Log.isWarningEnabled())
          {
            Log.warn("Unable to configure the module " + this.module.getName());
          }
          this.state = STATE_ERROR;
        }
      }
      return false;
    }
  
    /**
     * Returns the module managed by this state implementation.
     *
     * @return the module.
     */
    public Module getModule()
    {
      return this.module;
    }
  
    /**
     * Returns the current state of the module. This method returns either
     * STATE_NEW, STATE_CONFIGURED, STATE_INITIALIZED or STATE_ERROR.
     *
     * @return the module state.
     */
    public int getState()
    {
      return this.state;
    }
  
    /**
     * Initializes the contained module and raises the set of the module to
     * STATE_INITIALIZED, if the module was not yet initialized. In case of an
     * error, the module state will be set to STATE_ERROR and the module will
     * not be available.
     *
     * @param subSystem  the sub-system.
     * 
     * @return true, if the module was successfully initialized, false otherwise.
     */
    public boolean initialize(final SubSystem subSystem)
    {
      if (this.state == STATE_CONFIGURED)
      {
        try
        {
            this.module.initialize(subSystem);
            this.state = STATE_INITIALIZED;
            return true;
        }
        catch (NoClassDefFoundError noClassDef)
        {
          Log.warn (new Log.SimpleMessage("Unable to load module classes for ",
                  this.module.getName(), ":", noClassDef.getMessage()));
          this.state = STATE_ERROR;
        }
        catch (ModuleInitializeException me)
        {
          if (Log.isDebugEnabled())
          {
            // its still worth a warning, but now we are more verbose ...
            Log.warn("Unable to initialize the module " + this.module.getName(), me);
          }
          else if (Log.isWarningEnabled())
          {
            Log.warn("Unable to initialize the module " + this.module.getName());
          }
          this.state = STATE_ERROR;
        }
        catch (Exception e)
        {
          if (Log.isDebugEnabled())
          {
            // its still worth a warning, but now we are more verbose ...
            Log.warn("Unable to initialize the module " + this.module.getName(), e);
          }
          else if (Log.isWarningEnabled())
          {
            Log.warn("Unable to initialize the module " + this.module.getName());
          }
          this.state = STATE_ERROR;
        }
      }
      return false;
    }
  
    /**
     * Compares this object with the given other object for equality. 
     * @see java.lang.Object#equals(java.lang.Object)
     * 
     * @param o the other object to be compared
     * @return true, if the other object is also a PackageState containing
     * the same module, false otherwise. 
     */
    public boolean equals(final Object o)
    {
      if (this == o)
      {
        return true;
      }
      if (!(o instanceof PackageState))
      {
        return false;
      }
  
      final PackageState packageState = (PackageState) o;
  
      if (!this.module.getModuleClass().equals(packageState.module.getModuleClass()))
      {
        return false;
      }
  
      return true;
    }
  
    /**
     * Computes a hashcode for this package state. 
     * @see java.lang.Object#hashCode()
     * 
     * @return the hashcode.
     */
    public int hashCode()
    {
      return this.module.hashCode();
    }
  }
  