abstractmodule.java

该源代码为一些通用的程序

        return;
      }

      final String line = lastLineRead.trim();
      final String key = parseKey(line);
      if (key != null)
      {
        // parse error: Non data line does not contain a colon
        final String b = readValue(reader, parseValue(line.trim()));

        if (key.equals("name"))
        {
          setName(b);
        }
        else if (key.equals("producer"))
        {
          setProducer(b);
        }
        else if (key.equals("description"))
        {
          setDescription(b);
        }
        else if (key.equals("subsystem"))
        {
          setSubSystem(b);
        }
        else if (key.equals("version.major"))
        {
          setMajorVersion(b);
        }
        else if (key.equals("version.minor"))
        {
          setMinorVersion(b);
        }
        else if (key.equals("version.patchlevel"))
        {
          setPatchLevel(b);
        }
      }
    }
  }

  /**
   * Parses an string to find the key section of the line. This section ends with
   * an colon.
   *
   * @param line the line which to parse
   * @return the key or null if no key is found.
   */
  private String parseKey(final String line)
  {
    final int idx = line.indexOf(':');
    if (idx == -1)
    {
      return null;
    }
    return line.substring(0, idx);
  }

  /**
   * Parses the value section of the given line.
   *
   * @param line the line that should be parsed
   * @return the value, never null
   */
  private String parseValue(final String line)
  {
    final int idx = line.indexOf(':');
    if (idx == -1)
    {
      return line;
    }
    if ((idx + 1) == line.length())
    {
      return "";
    }
    return line.substring(idx + 1);
  }

  /**
   * Reads an external module description. This describes either an optional or
   * a required module.
   *
   * @param reader the reader from where to read the module
   * @return the read module, never null
   * @throws IOException if an error occures.
   */
  private DefaultModuleInfo readExternalModule(final ReaderHelper reader)
      throws IOException
  {
    final DefaultModuleInfo mi = new DefaultModuleInfo();

    while (reader.hasNext())
    {
      final String lastLineRead = reader.next();

      if (Character.isWhitespace(lastLineRead.charAt(0)) == false)
      {
        // break if the current character is no whitespace ...
        reader.pushBack(lastLineRead);
        return mi;
      }

      final String line = lastLineRead.trim();
      final String key = parseKey(line);
      if (key != null)
      {
        final String b = readValue(reader, parseValue(line));
        if (key.equals("module"))
        {
          mi.setModuleClass(b);
        }
        else if (key.equals("version.major"))
        {
          mi.setMajorVersion(b);
        }
        else if (key.equals("version.minor"))
        {
          mi.setMinorVersion(b);
        }
        else if (key.equals("version.patchlevel"))
        {
          mi.setPatchLevel(b);
        }
      }
    }
    return mi;
  }

  /**
   * Returns the name of this module.
   *
   * @see Module#getName()
   *
   * @return the module name
   */
  public String getName()
  {
    return this.name;
  }

  /**
   * Defines the name of the module.
   *
   * @param name the module name.
   */
  protected void setName(final String name)
  {
    this.name = name;
  }

  /**
   * Returns the module description.
   * @see Module#getDescription()
   *
   * @return the description of the module.
   */
  public String getDescription()
  {
    return this.description;
  }

  /**
   * Defines the description of the module.
   *
   * @param description the module's desciption.
   */
  protected void setDescription(final String description)
  {
    this.description = description;
  }

  /**
   * Returns the producer of the module.
   *
   * @see Module#getProducer()
   *
   * @return the producer.
   */
  public String getProducer()
  {
    return this.producer;
  }

  /**
   * Defines the producer of the module.
   *
   * @param producer the producer.
   */
  protected void setProducer(final String producer)
  {
    this.producer = producer;
  }

  /**
   * Returns a copy of the required modules array. This array contains all
   * description of the modules that need to be present to make this module work.
   * @see Module#getRequiredModules()
   *
   * @return an array of all required modules.
   */
  public ModuleInfo[] getRequiredModules()
  {
    final ModuleInfo[] retval = new ModuleInfo[this.requiredModules.length];
    System.arraycopy(this.requiredModules, 0, retval, 0, this.requiredModules.length);
    return retval;
  }

  /**
   * Returns a copy of the required modules array. This array contains all
   * description of the optional modules that may improve the modules functonality.
   * @see Module#getRequiredModules()
   *
   * @return an array of all required modules.
   */
  public ModuleInfo[] getOptionalModules()
  {
    final ModuleInfo[] retval = new ModuleInfo[this.optionalModules.length];
    System.arraycopy(this.optionalModules, 0, retval, 0, this.optionalModules.length);
    return retval;
  }

  /**
   * Defines the required module descriptions for this module.
   *
   * @param requiredModules the required modules.
   */
  protected void setRequiredModules(final ModuleInfo[] requiredModules)
  {
    this.requiredModules = new ModuleInfo[requiredModules.length];
    System.arraycopy(requiredModules, 0, this.requiredModules, 0, requiredModules.length);
  }

  /**
   * Defines the optional module descriptions for this module.
   *
   * @param optionalModules the optional modules.
   */
  public void setOptionalModules(final ModuleInfo[] optionalModules)
  {
    this.optionalModules = new ModuleInfo[optionalModules.length];
    System.arraycopy(optionalModules, 0, this.optionalModules, 0, optionalModules.length);
  }

  /**
   * Returns a string representation of this module.
   * @see java.lang.Object#toString()
   *
   * @return the string representation of this module for debugging purposes.
   */
  public String toString()
  {
    final StringBuffer buffer = new StringBuffer();
    buffer.append("Module : ");
    buffer.append(getName());
    buffer.append("\n");
    buffer.append("ModuleClass : ");
    buffer.append(getModuleClass());
    buffer.append("\n");
    buffer.append("Version: ");
    buffer.append(getMajorVersion());
    buffer.append(".");
    buffer.append(getMinorVersion());
    buffer.append(".");
    buffer.append(getPatchLevel());
    buffer.append("\n");
    buffer.append("Producer: ");
    buffer.append(getProducer());
    buffer.append("\n");
    buffer.append("Description: ");
    buffer.append(getDescription());
    buffer.append("\n");
    return buffer.toString();
  }

  /**
   * Tries to load a class to indirectly check for the existence
   * of a certain library.
   *
   * @param name the name of the library class.
   * @return true, if the class could be loaded, false otherwise.
   */
  protected static boolean isClassLoadable(final String name)
  {
    try
    {
      Thread.currentThread().getContextClassLoader().loadClass(name);
      return true;
    }
    catch (Exception e)
    {
      return false;
    }
  }

  /**
   * Configures the module by loading the configuration properties and
   * adding them to the package configuration.
   * 
   * @param subSystem  the subsystem.
   */
  public void configure(final SubSystem subSystem)
  {
    final InputStream in = ObjectUtilities.getResourceRelativeAsStream
            ("configuration.properties", getClass());
    if (in == null)
    {
      return;
    }
    subSystem.getPackageManager().getPackageConfiguration().load(in);
  }

  /**
   * Tries to load an module initializer and uses this initializer to initialize
   * the module.
   *
   * @param classname the class name of the initializer.
   * @throws ModuleInitializeException if an error occures
   */
  protected void performExternalInitialize(final String classname)
      throws ModuleInitializeException
  {
    try
    {
      final Class c = Thread.currentThread().getContextClassLoader().loadClass(classname);
      final ModuleInitializer mi = (ModuleInitializer) c.newInstance();
      mi.performInit();
    }
    catch (ModuleInitializeException mie)
    {
      throw mie;
    }
    catch (Exception e)
    {
      throw new ModuleInitializeException("Failed to load specified initializer class.", e);
    }
  }

  /**
   * Returns the modules subsystem. If this module is not part of an subsystem
   * then return the modules name, but never null.
   *
   * @return the name of the subsystem.
   */
  public String getSubSystem()
  {
    if (this.subsystem == null)
    {
      return getName();
    }
    return this.subsystem;
  }

  /**
   * Defines the subsystem name for this module.
   *
   * @param name the new name of the subsystem.
   */
  protected void setSubSystem (final String name)
  {
    this.subsystem = name;
  }
}