    001// Copyright 2007, 2008, 2010 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.Translator;
    018import org.apache.tapestry5.ioc.annotations.UsesMappedConfiguration;
    019import org.apache.tapestry5.ioc.util.StrategyRegistry;
    020
    021/**
    022 * A source for {@link org.apache.tapestry5.Translator}s, either by name or by property type. The source knows
    023 * about two sets of translators: the <em>standard</em> translators contributed directly to the service
    024 * and the <em>alternate</em> translators, contributed to the {@link TranslatorAlternatesSource} service.
    025 * <p/>
    026 * Each contributed translator must have a unique {@linkplain org.apache.tapestry5.Translator#getName() name}.
    027 * <p>
    028 * Generally, Translators are matched by type (i.e., the type matching a particular property that will be read or
    029 * updated). Contributions to this service use a {@link StrategyRegistry} to match by type. Translators can also be
    030 * selected by name. The {@link TranslatorAlternatesSource} service configuration is often used for this purpose.
    031 * <p>
    032 * The contribution key must match the {@linkplain Translator#getType() translator type}.
    033 */
    034@UsesMappedConfiguration(key=Class.class, value=Translator.class)
    035@SuppressWarnings("unchecked")
    036public interface TranslatorSource
    037{
    038    /**
    039     * Returns the translator with the given name (either a standard translator, or an alternate).
    040     *
    041     * @param name
    042     *            name of translator (as configured, but case is ignored)
    043     * @return the shared translator instance
    044     * @throws RuntimeException
    045     *             if no translator is configured for the provided name
    046     */
    047    Translator get(String name);
    048
    049    /**
    050     * Finds a {@link Translator} that is appropriate to the given type, which is usually obtained via
    051     * {@link org.apache.tapestry5.Binding#getBindingType()}. Performs an inheritance-based search for the best match,
    052     * among the <em>standard</em> translator (not alternates).
    053     *
    054     * @param valueType
    055     *            the type of value for which a default translator is needed
    056     * @return the matching translator, or null if no match can be found
    057     */
    058    Translator findByType(Class valueType);
    059
    060    /**
    061     * Finds a {@link Translator} that is appropriate to the given type, which is usually obtained via
    062     * {@link org.apache.tapestry5.Binding#getBindingType()}. Performs an inheritance-based search for the best match,
    063     * among the <em>standard</em> translators (not alternates).
    064     *
    065     * @param valueType
    066     *            the type of value for which a default translator is needed
    067     * @return the matching translator
    068     * @throws IllegalArgumentException
    069     *             if no standard validator matches the provided type
    070     */
    071    Translator getByType(Class valueType);
    072}