001// Copyright 2007, 2008, 2011 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007//     http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry5.services;
016
017import org.apache.tapestry5.ioc.annotations.UsesMappedConfiguration;
018import org.apache.tapestry5.ioc.annotations.UsesOrderedConfiguration;
019import org.apache.tapestry5.ioc.services.PropertyAdapter;
020
021/**
022 * Used by {@link BeanModelSource} to identify the type of data associated with a particular property (represented as a
023 * {@link PropertyAdapter}). The data type is a string used to determine what kind of interface to use for displaying
024 * the value of the property, or what kind of interface to use for editing the value of the property. Common property
025 * types are "text", "enum", "checkbox", but the list is extensible.
026 * <p/>
027 * Different strategies for identifying the data type are encapsulated in the DataTypeAnalyzer service, forming a
028 * chain of command.
029 * <p/>
030 * The DefaultDataTypeAnalyzer service maps property types to data type names.
031 * <p/>
032 * The DataTypeAnalyzer service is an extensible {@linkplain org.apache.tapestry5.ioc.services.ChainBuilder chain of
033 * command}), that (by default) includes {@link org.apache.tapestry5.internal.services.AnnotationDataTypeAnalyzer} and
034 * the {@link org.apache.tapestry5.internal.services.DefaultDataTypeAnalyzer} service (ordered last).   It uses an ordered configuration.
035 *
036 * @see org.apache.tapestry5.corelib.components.Grid
037 * @see org.apache.tapestry5.corelib.components.BeanEditForm
038 * @see BeanBlockSource
039 */
040@UsesOrderedConfiguration(DataTypeAnalyzer.class)
041@UsesMappedConfiguration(key = Class.class, value = String.class)
042public interface DataTypeAnalyzer
043{
044    /**
045     * Identifies the data type, if known, or returns null if not known.
046     */
047    String identifyDataType(PropertyAdapter adapter);
048}