| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache 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.apache.org/licenses/LICENSE-2.0 |
| * |
| * 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.apache.cocoon.forms.formmodel; |
| |
| import java.util.Iterator; |
| |
| import org.apache.cocoon.forms.datatype.Datatype; |
| |
| /** |
| * Common interface for an algorithm to calculate the value of a |
| * {@link org.apache.cocoon.forms.formmodel.CalculatedField}. |
| * |
| * @version $Id$ |
| */ |
| public interface CalculatedFieldAlgorithm { |
| |
| /** |
| * Checks wether this algorithm is able to return the given datatype. For example, |
| * an arithmetic algorithm like sum should check that the given datatype is a number. |
| * @param dataType The target datatype. |
| * @return true if this algorithm can return a compatible value, false otherwise. |
| */ |
| public boolean isSuitableFor(Datatype dataType); |
| |
| /** |
| * Performs the actual calculation. |
| * @param form The form. |
| * @param parent The parent widget of the {@link CalculatedField} widget (may be the same as form) |
| * @param datatype The target datatype. |
| * @return the calculated value for the {@link CalculatedField}. |
| */ |
| public Object calculate(Form form, Widget parent, Datatype datatype); |
| |
| /** |
| * Returns an iterator on trigger widget paths. When the value of a trigger widget changes, |
| * then the {@link CalculatedField} value must be recalculated. |
| * @return An iterator of Strings representing widget paths as interpreted by {@link org.apache.cocoon.forms.util.WidgetFinder}. |
| */ |
| public Iterator getTriggerWidgets(); |
| |
| } |