    001// Copyright 2009 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.commons.internal.services;
    016
    017/**
    018 * Creates "interned" strings that are unique for the same content. This is used for common description strings,
    019 * particularly those used by {@link org.apache.tapestry5.Binding} instances.  The internal cache of interned strings id
    020 * cleared whenever the {@link org.apache.tapestry5.ioc.annotations.ComponentClasses}
    021 * <a href="https://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/InvalidationEventHub.html">InvalidationEventHub</a> is invalidated (i.e., when component class files change).
    022 *
    023 * @since 5.1.0.0
    024 */
    025public interface StringInterner
    026{
    027    /**
    028     * Interns a string.
    029     *
    030     * @param string the string to intern
    031     * @return the input string, or another string instance with the same content
    032     */
    033    String intern(String string);
    034
    035    /**
    036     * Formats a string (using {@link String#format(String, Object[])}) and returns the interned result.
    037     *
    038     * @param format    string format
    039     * @param arguments used inside the format
    040     * @return formatted and interned string
    041     */
    042    String format(String format, Object... arguments);
    043}