/**

  * Copyright 2005-2011 The Kuali Foundation

  *

  * Licensed under the Educational Community License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  *

  * http://www.opensource.org/licenses/ecl2.php

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.kuali.rice.kew.api.document.attribute;

 /**

  * Defines the contract for an attribute of a document.  These attributes are generally extracted during an indexing

  * process and stored as key-value pairs associated with the document.  In addition to the key-value pair, the

  * document attribute also defines the data type of data that is held by the attribute.

  *

  * <p>This contract simply defines the interface that specific (and strongly typed) implementations of document

  * attributes will implement.  The number of possible implementations of this contract are generally constrainted by

  * the set of defined {@link DocumentAttributeDataType} enumeration values.</p>

  *

  * <p>Concrete instances of should be created using the {@link DocumentAttributeFactory}.  It is not generally

  * of value for a client of the API to create custom implementations of this contract interface.</p>

  *

  * @see DocumentAttributeFactory

  *

  * @author Kuali Rice Team (rice.collab@kuali.org)

  */

 public interface DocumentAttributeContract {

     /**

      * Returns the name of this document attribute which serves as an identifier for this attribute on the document.  A

      * document may have more then one attribute with the same name, in which case it is treated as a multi-valued

      * attribute.  This method should never return a null or blank value.

      *

      * @return the name of the document attribute

      */

     String getName();

     /**

      * Returns the value of this document attribute.  It can be of any type as defined by the implementations of this

      * interface.  It is possible that this value may be null in cases where the document has a particular attribute

      * but no actual value associated with that attribute.

      *

      * @return the value of the document attribute

      */

     Object getValue();

     /**

      * Returns the data type of this document attribute.  This will generally inform the type of object returned from

      * the {@code #getValue} method.  This method should never return a null value.

      *

      * @return the data type of this document attribute

      */

     DocumentAttributeDataType getDataType();

 }