    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
    015    package org.apache.tapestry5.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.services.ComponentClasses} {@link
    021     * org.apache.tapestry5.services.InvalidationEventHub} is invalidated (i.e., when component class files change).
    022     *
    023     * @since 5.1.0.0
    024     */
    025    public 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    }