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From blorit...@apache.org
Subject cvs commit: jakarta-avalon/src/proposal/avalon5/org/apache/framework/component/impl DefaultComponentLocator.java DefaultComponentManager.java
Date Thu, 13 Jun 2002 21:49:33 GMT
bloritsch    2002/06/13 14:49:33

  Modified:    src/proposal/avalon5/org/apache/framework/component
                        ComponentException.java Composable.java
  Added:       src/proposal/avalon5/org/apache/framework/component
                        ComponentLocator.java
               src/proposal/avalon5/org/apache/framework/component/impl
                        DefaultComponentLocator.java
  Removed:     src/proposal/avalon5/org/apache/framework/component
                        ComponentManager.java
               src/proposal/avalon5/org/apache/framework/component/impl
                        DefaultComponentManager.java
  Log:
  change proposal name for ComponentManager to ComponentLocator
  
  Revision  Changes    Path
  1.2       +2 -2      jakarta-avalon/src/proposal/avalon5/org/apache/framework/component/ComponentException.java
  
  Index: ComponentException.java
  ===================================================================
  RCS file: /home/cvs/jakarta-avalon/src/proposal/avalon5/org/apache/framework/component/ComponentException.java,v
  retrieving revision 1.1
  retrieving revision 1.2
  diff -u -r1.1 -r1.2
  --- ComponentException.java	7 Jun 2002 20:04:11 -0000	1.1
  +++ ComponentException.java	13 Jun 2002 21:49:33 -0000	1.2
  @@ -9,7 +9,7 @@
   
   /**
    * The exception thrown to indicate a problem with service.
  - * It is usually thrown by ComponentManager or ServiceSelector.
  + * It is usually thrown by ComponentLocator or ServiceSelector.
    *
    * @author <a href="mailto:peter@apache.org">Peter Donald</a>
    * @author <a href="mailto:fumagalli@exoffice.com">Pierpaolo Fumagalli</a>
  @@ -18,7 +18,7 @@
    * @author <a href="mailto:mcconnell@apache.org">Stephen McConnell</a>
    */
   public class ComponentException
  -    extends RuntimeException
  +    extends Exception
   {
       /**
        * The Throwable that caused this exception to be thrown.
  
  
  
  1.2       +6 -6      jakarta-avalon/src/proposal/avalon5/org/apache/framework/component/Composable.java
  
  Index: Composable.java
  ===================================================================
  RCS file: /home/cvs/jakarta-avalon/src/proposal/avalon5/org/apache/framework/component/Composable.java,v
  retrieving revision 1.1
  retrieving revision 1.2
  diff -u -r1.1 -r1.2
  --- Composable.java	7 Jun 2002 20:04:11 -0000	1.1
  +++ Composable.java	13 Jun 2002 21:49:33 -0000	1.2
  @@ -15,7 +15,7 @@
    *
    * The contract surrounding a <code>Composable</code> is that it is a user.
    * The <code>Composable</code> is able to use <code>Object</code>s
managed
  - * by the <code>ComponentManager</code> it was initialized with.  As part
  + * by the <code>ComponentLocator</code> it was initialized with.  As part
    * of the contract with the system, the instantiating entity must call
    * the <code>compose</code> method before the <code>Composable</code>
    * can be considered valid.
  @@ -26,21 +26,21 @@
    * @author <a href="mailto:bloritsch@apache.org">Berin Loritsch</a>
    * @author <a href="mailto:mcconnell@apache.org">Stephen McConnell</a>
    * @version 1.0
  - * @see org.apache.framework.component.ComponentManager
  + * @see org.apache.framework.component.ComponentLocator
    *
    */
   public interface Composable
   {
       /**
  -     * Pass the <code>ComponentManager</code> to the <code>Composable</code>.
  +     * Pass the <code>ComponentLocator</code> to the <code>Composable</code>.
        * The <code>Composable</code> implementation should use the specified
  -     * <code>ComponentManager</code> to acquire the components it needs for
  +     * <code>ComponentLocator</code> to acquire the components it needs for
        * execution.
        *
  -     * @param manager The <code>ComponentManager</code> which this
  +     * @param manager The <code>ComponentLocator</code> which this
        *                <code>Composable</code> uses.
        * @exception ComponentException if an error occurs
        */
  -    void compose( ComponentManager manager )
  +    void compose( ComponentLocator manager )
           throws ComponentException;
   }
  
  
  
  1.1                  jakarta-avalon/src/proposal/avalon5/org/apache/framework/component/ComponentLocator.java
  
  Index: ComponentLocator.java
  ===================================================================
  /*
   * Copyright (C) The Apache Software Foundation. All rights reserved.
   *
   * This software is published under the terms of the Apache Software License
   * version 1.1, a copy of which has been included with this distribution in
   * the LICENSE.txt file.
   */
  package org.apache.framework.component;
  
  /**
   * A <code>ComponentLocator</code> selects <code>Object</code>s
based on a
   * role.  The contract is that all the <code>Object</code>s implement the
   * differing roles and there is one <code>Object</code> per role.  If you
   * need to select on of many <code>Object</code>s that implement the same
   * role, then you need to use a <code>ServiceSelector</code>.  Roles are
   * usually the full interface name.
   *
   * A role is better understood by the analogy of a play.  There are many
   * different roles in a script.  Any actor or actress can play any given part
   * and you get the same results (phrases said, movements made, etc.).  The exact
   * nuances of the performance is different.
   *
   * Below is a list of things that might be considered the different roles:
   *
   * <ul>
   *   <li> InputAdaptor and OutputAdaptor</li>
   *   <li> Store and Spool</li>
   * </ul>
   *
   * The <code>ComponentLocator</code> does not specify the methodology of
   * getting the <code>Object</code>, merely the interface used to get it.
   * Therefore the <code>ComponentLocator</code> can be implemented with a
   * factory pattern, an object pool, or a simple Hashtable.
   *
   * @author <a href="mailto:scoobie@betaversion.org">Federico Barbieri</a>
   * @author <a href="mailto:stefano@apache.org">Stefano Mazzocchi</a>
   * @author <a href="mailto:fumagalli@exoffice.com">Pierpaolo Fumagalli</a>
   * @author <a href="mailto:bloritsch@apache.org">Berin Loritsch</a>
   * @author <a href="mailto:mcconnell@apache.org">Stephen McConnell</a>
   * @version 1.0
   * @see org.apache.framework.component.Composable
   */
  public interface ComponentLocator
  {
      /**
       * Get the <code>Object</code> associated with the given role.  For
       * instance, If the <code>ComponentLocator</code> had a
       * <code>LoggerComponent</code> stored and referenced by role, I would use
       * the following call:
       * <pre>
       * try
       * {
       *     MyComponent log;
       *     myComponent = (MyComponent) manager.lookup(MyComponent.ROLE);
       * }
       * catch (...)
       * {
       *     ...
       * }
       * </pre>
       *
       * @param role The role name of the <code>Object</code> to retrieve.
       * @return an <code>Object</code> value
       * @throws ComponentException if the component is not available
       */
      Object lookup( String role ) throws ComponentException;
  
      /**
       * Get the <code>Object</code> associated with the given role.  For
       * instance, If the <code>ComponentLocator</code> had a
       * <code>LoggerComponent</code> stored and referenced by role, I would use
       * the following call:
       * <pre>
       * try
       * {
       *     MyComponent log;
       *     myComponent = (MyComponent) manager.lookup(MyComponent.ROLE,
       *                                                "myhint");
       * }
       * catch (...)
       * {
       *     ...
       * }
       * </pre>
       *
       * @param role The role name of the <code>Object</code> to retrieve.
       * @return an <code>Object</code> value
       * @throws ComponentException if the component is not available
       */
      Object lookup( String role, Object hint ) throws ComponentException;
  
      /**
       * Check to see if a <code>Object</code> exists for a role.
       *
       * @param role  a string identifying the role to check.
       * @return True if the object exists, False if it does not.
       */
      boolean exists( String role );   
  }
  
  
  
  1.1                  jakarta-avalon/src/proposal/avalon5/org/apache/framework/component/impl/DefaultComponentLocator.java
  
  Index: DefaultComponentLocator.java
  ===================================================================
  /*
   * Copyright (C) The Apache Software Foundation. All rights reserved.
   *
   * This software is published under the terms of the Apache Software License
   * version 1.1, a copy of which has been included with this distribution in
   * the LICENSE.txt file.
   */
  package org.apache.framework.component.impl;
  
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.Map;
  import org.apache.framework.component.ComponentLocator;
  import org.apache.framework.component.ComponentException;
  
  /**
   * This class is a static implementation of a ComponentLocator. Allow ineritance
   * and extension so you can generate a tree of ComponentLocator each defining
   * Object scope.
   *
   * @author <a href="mailto:fede@apache.org">Federico Barbieri</a>
   * @author <a href="mailto:peter@apache.org">Peter Donald</a>
   * @author <a href="mailto:mcconnell@apache.org">Stephen McConnell</a>
   * @version 1.0
   */
  public class DefaultComponentLocator
      implements ComponentLocator
  {
      private final HashMap               m_objects = new HashMap();
      private final ComponentLocator      m_parent;
      private boolean                     m_readOnly;
  
      /**
       * Construct ComponentLocator with no parent.
       *
       */
      public DefaultComponentLocator()
      {
          this( null );
      }
  
      /**
       * Construct ComponentLocator with specified parent.
       *
       * @param parent the ComponentLocator parent
       */
      public DefaultComponentLocator( final ComponentLocator parent )
      {
          m_parent = parent;
      }
  
      /**
       * Retrieve Object by role from ComponentLocator.
       *
       * @param role the role
       * @return the Object
       * @exception org.apache.framework.component.ComponentException if an error occurs
       */
      public Object lookup( final String role )
          throws ComponentException
      {
          return lookup( role, null );
      }
  
      /**
       * Retrieve Object by role/hint from ComponentLocator.
       *
       * @param role the role
       * @return the Object
       * @exception org.apache.framework.component.ComponentException if an error occurs
       */
      public Object lookup( final String role, Object hint )
          throws ComponentException
      {
          // the default version of the method ignores the hint
          final Object object = m_objects.get( role );
  
          if( null != object )
          {
              return object;
          }
          else if( null != m_parent )
          {
              return m_parent.lookup( role );
          }
          else
          {
              throw new ComponentException( "Unable to provide implementation for " + role
);
          }
      }
  
      /**
       * Check to see if a <code>Object</code> exists for a role.
       *
       * @param role  a string identifying the role to check.
       * @return True if the object exists, False if it does not.
       */
      public boolean exists( final String role )
      {
          boolean objectExists = false;
  
          try
          {
              this.lookup(role);
              objectExists = true;
          }
          catch (Throwable t)
          {
              // Ignore all throwables--we want a yes or no answer.
          }
          return objectExists;
      }
  
      /**
       * Place Object into ComponentLocator.
       *
       * @param role the components role
       * @param object an <code>Object</code> value
       */
      public void put( final String role, final Object object )
      {
          checkWriteable();
          m_objects.put( role, object );
      }
  
      /**
       * Build a human readable representation of the ComponentLocator.
       *
       * @return the description of the ComponentLocator
       */
      public String toString()
      {
          final StringBuffer buffer = new StringBuffer();
          final Iterator objects = m_objects.keySet().iterator();
          buffer.append( "Services:" );
  
          while( objects.hasNext() )
          {
              buffer.append( "[" );
              buffer.append( objects.next() );
              buffer.append( "]" );
          }
  
          return buffer.toString();
      }
  
      /**
       * Helper method for subclasses to retrieve parent.
       *
       * @return the parent ComponentLocator
       */
      protected final ComponentLocator getParent()
      {
          return m_parent;
      }
  
      /**
       * Helper method for subclasses to retrieve object map.
       *
       * @return the object map
       */
      protected final Map getObjectMap()
      {
          return m_objects;
      }
  
      /**
       * Makes this service manager read-only.
       *
       */
      public void makeReadOnly()
      {
          m_readOnly = true;
      }
  
      /**
       * Checks if this service manager is writeable.
       *
       * @exception java.lang.IllegalStateException if this service manager is read-only
       */
      protected final void checkWriteable()
          throws IllegalStateException
      {
          if( m_readOnly )
          {
              throw new IllegalStateException
                  ( "ComponentLocator is read only and can not be modified" );
          }
      }
  
      
  }
  
  
  

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