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