001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing,
013     * software distributed under the License is distributed on an
014     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015     * KIND, either express or implied.  See the License for the
016     * specific language governing permissions and limitations
017     * under the License.
018     */
019    package org.apache.shiro.config;
020    
021    import org.apache.shiro.io.ResourceUtils;
022    import org.apache.shiro.util.AbstractFactory;
023    import org.apache.shiro.util.CollectionUtils;
024    import org.apache.shiro.util.Factory;
025    import org.slf4j.Logger;
026    import org.slf4j.LoggerFactory;
027    
028    /**
029     * Base support class for {@link Factory} implementations that generate their instance(s) based on
030     * {@link Ini} configuration.
031     *
032     * @since 1.0
033     */
034    public abstract class IniFactorySupport<T> extends AbstractFactory<T> {
035    
036        public static final String DEFAULT_INI_RESOURCE_PATH = "classpath:shiro.ini";
037    
038        private static transient final Logger log = LoggerFactory.getLogger(IniFactorySupport.class);
039    
040        private Ini ini;
041    
042        protected IniFactorySupport() {
043        }
044    
045        protected IniFactorySupport(Ini ini) {
046            this.ini = ini;
047        }
048    
049        public Ini getIni() {
050            return ini;
051        }
052    
053        public void setIni(Ini ini) {
054            this.ini = ini;
055        }
056    
057        /**
058         * Returns a new Ini instance created from the default {@code classpath:shiro.ini} file, or {@code null} if
059         * the file does not exist.
060         *
061         * @return a new Ini instance created from the default {@code classpath:shiro.ini} file, or {@code null} if
062         *         the file does not exist.
063         */
064        public static Ini loadDefaultClassPathIni() {
065            Ini ini = null;
066            if (ResourceUtils.resourceExists(DEFAULT_INI_RESOURCE_PATH)) {
067                log.debug("Found shiro.ini at the root of the classpath.");
068                ini = new Ini();
069                ini.loadFromPath(DEFAULT_INI_RESOURCE_PATH);
070                if (CollectionUtils.isEmpty(ini)) {
071                    log.warn("shiro.ini found at the root of the classpath, but it did not contain any data.");
072                }
073            }
074            return ini;
075        }
076    
077        /**
078         * Tries to resolve the Ini instance to use for configuration.  This implementation functions as follows:
079         * <ol>
080         * <li>The {@code Ini} instance returned from {@link #getIni()} will be returned if it is not null or empty.</li>
081         * <li>If {@link #getIni()} is {@code null} or empty, this implementation will attempt to find and load the
082         * {@link #loadDefaultClassPathIni() default class path Ini}.</li>
083         * <li>If neither of the two attempts above returns an instance, {@code null} is returned</li>
084         * </ol>
085         *
086         * @return the Ini instance to use for configuration.
087         */
088        protected Ini resolveIni() {
089            Ini ini = getIni();
090            if (CollectionUtils.isEmpty(ini)) {
091                log.debug("Null or empty Ini instance.  Falling back to the default {} file.", DEFAULT_INI_RESOURCE_PATH);
092                ini = loadDefaultClassPathIni();
093            }
094            return ini;
095        }
096    
097        /**
098         * Creates a new object instance by using a configured INI source.  This implementation functions as follows:
099         * <ol>
100         * <li>{@link #resolveIni() Resolve} the {@code Ini} source to use for configuration.</li>
101         * <li>If there was no resolved Ini source, create and return a simple default instance via the
102         * {@link #createDefaultInstance()} method.</li>
103         * </ol>
104         *
105         * @return a new {@code SecurityManager} instance by using a configured INI source.
106         */
107        public T createInstance() {
108            Ini ini = resolveIni();
109    
110            T instance;
111    
112            if (CollectionUtils.isEmpty(ini)) {
113                log.debug("No populated Ini available.  Creating a default instance.");
114                instance = createDefaultInstance();
115                if (instance == null) {
116                    String msg = getClass().getName() + " implementation did not return a default instance in " +
117                            "the event of a null/empty Ini configuration.  This is required to support the " +
118                            "Factory interface.  Please check your implementation.";
119                    throw new IllegalStateException(msg);
120                }
121            } else {
122                log.debug("Creating instance from Ini [" + ini + "]");
123                instance = createInstance(ini);
124                if (instance == null) {
125                    String msg = getClass().getName() + " implementation did not return a constructed instance from " +
126                            "the createInstance(Ini) method implementation.";
127                    throw new IllegalStateException(msg);
128                }
129            }
130    
131            return instance;
132        }
133    
134        protected abstract T createInstance(Ini ini);
135    
136        protected abstract T createDefaultInstance();
137    }