001/*
002 *  Copyright 2018 Anyware Services
003 *
004 *  Licensed under the Apache License, Version 2.0 (the "License");
005 *  you may not use this file except in compliance with the License.
006 *  You may obtain a copy of the License at
007 *
008 *      http://www.apache.org/licenses/LICENSE-2.0
009 *
010 *  Unless required by applicable law or agreed to in writing, software
011 *  distributed under the License is distributed on an "AS IS" BASIS,
012 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 *  See the License for the specific language governing permissions and
014 *  limitations under the License.
015 */
016package org.ametys.runtime.model;
017
018import java.util.Collections;
019import java.util.Map;
020
021import org.ametys.runtime.i18n.I18nizableText;
022
023/**
024 * Enumerator for listing values.<p>
025 * Such values usually depends on environment (directory listing, DB table, ...).
026 * @param <T> Type of the values
027 */
028public interface Enumerator<T>
029{
030    /**
031     * Retrieves a single label from a value.
032     * @param value the value.
033     * @return the label or <code>null</code> if not found.
034     * @throws Exception if an error occurs.
035     */
036    public default I18nizableText getEntry(T value) throws Exception
037    {
038        return getEntries().get(value);
039    }
040    
041    /**
042     * Retrieves a single label from a value.
043     * @param value the value.
044     * @param contextualParameters Contextual parameters that may change enumeration. See enumerator implementation to see available parameters.
045     * @return the label or <code>null</code> if not found.
046     * @throws Exception if an error occurs.
047     */
048    public default I18nizableText getEntry(T value, Map<String, Object> contextualParameters) throws Exception
049    {
050        return getEntries(contextualParameters).get(value);
051    }
052    
053    /**
054     * Provides the enumerated values with their optional label.
055     * @return the enumerated values and their label.
056     * @throws Exception if an error occurs.
057     */
058    public Map<T, I18nizableText> getEntries() throws Exception;
059    
060    /**
061     * Provides the enumerated values with their optional label.
062     * @param contextualParameters Contextual parameters that may change enumeration. See enumerator implementation to see available parameters.
063     * @return the enumerated values and their label.
064     * @throws Exception if an error occurs.
065     */
066    public default Map<T, I18nizableText> getEntries(Map<String, Object> contextualParameters) throws Exception
067    {
068        return getEntries();
069    }
070    
071    /**
072     * Get the configuration of this enumerator
073     * @return the configuration
074     */
075    public default Map<String, Object> getConfiguration()
076    {
077        return Collections.EMPTY_MAP;
078    }
079    
080}