001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one
003 *  or more contributor license agreements.  See the NOTICE file
004 *  distributed with this work for additional information
005 *  regarding copyright ownership.  The ASF licenses this file
006 *  to you under the Apache License, Version 2.0 (the
007 *  "License"); you may not use this file except in compliance
008 *  with the License.  You may obtain a copy of the License at
009 *
010 *        http://www.apache.org/licenses/LICENSE-2.0
011 *
012 *  Unless required by applicable law or agreed to in writing,
013 *  software distributed under the License is distributed on an
014 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 *  KIND, either express or implied.  See the License for the
016 *  specific language governing permissions and limitations
017 *  under the License.
018 */
019
020package org.apache.isis.core.progmodel.facets.actions.validate;
021
022import org.apache.isis.core.metamodel.adapter.ObjectAdapter;
023import org.apache.isis.core.metamodel.facetapi.Facet;
024import org.apache.isis.core.metamodel.facets.actions.invoke.ActionInvocationFacet;
025import org.apache.isis.core.metamodel.interactions.ValidatingInteractionAdvisor;
026
027/**
028 * The mechanism by which the set of parameters of the action can be validated
029 * before the action itself is invoked.
030 * 
031 * <p>
032 * In the standard Apache Isis Programming Model, corresponds to invoking the
033 * <tt>validateXxx</tt> support method for an action.
034 * 
035 * <p>
036 * Note that the parameters may be validated independently first (eg a range
037 * check on a numeric parameter).
038 * 
039 * @see ActionInvocationFacet
040 */
041public interface ActionValidationFacet extends Facet, ValidatingInteractionAdvisor {
042
043    /**
044     * Reason why the validation has failed, or <tt>null</tt> if okay.
045     */
046    public String invalidReason(ObjectAdapter target, ObjectAdapter[] arguments);
047}