source: trunk/src/ws/fugue88/access/Accessor.java

/*
 * This code is copyright (c) 2005 David Owen.  All rights not explicitly
 * granted by the author are reserved.
 *
 * Created on Aug 2, 2005.
 */
package ws.fugue88.access;

import java.lang.reflect.InvocationTargetException;

/**
 * Provides parameterized bindings to specific references to objects (not
 * necessarily to specific objects).
 * 
 * @author dsowen
 */
public interface Accessor {

        /**
         * Returns the natural type of the reference bound by this accessor. This
         * should:
         * <ul>
         * <li>return the same type for every binding to the reference;</li>
         * <li>return that type independent of the actual type of the referenced
         * object; and,</li>
         * <li>return that type even if the reference is currently
         * <code>null</code> or non-existent.</li>
         * </ul>
         * 
         * @return
         */
        Class getType();

        /**
         * Clears the reference bound by this accessor. For references that may be
         * deleted without losing the ability to set it, it should be deleted (e.g.
         * the key in a map may be removed).
         * 
         * @throws InvocationTargetException
         */
        void clearValue() throws InvocationTargetException;

        /**
         * Returns the current object to which the reference refers. If the
         * reference does not exist, <code>null</code> should be returned.
         * 
         * @return the current value, or <code>null</code> if no reference
         * @throws InvocationTargetException
         */
        Object getValue() throws InvocationTargetException;

        /**
         * Sets the reference to refer to the given object. If the reference does
         * not exist, it is created.
         * 
         * @param value
         * @throws InvocationTargetException
         */
        void setValue(Object value) throws InvocationTargetException;
}