    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
    015    package org.apache.tapestry5.services;
    016
    017    import org.apache.tapestry5.Translator;
    018    import org.apache.tapestry5.ioc.annotations.UsesMappedConfiguration;
    019    import 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")
    036    public 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    }