| // *************************************************************************************************************************** |
| // * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file * |
| // * distributed with this work for additional information regarding copyright ownership. The ASF licenses this file * |
| // * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance * |
| // * with the License. You may obtain a copy of the License at * |
| // * * |
| // * http://www.apache.org/licenses/LICENSE-2.0 * |
| // * * |
| // * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an * |
| // * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the * |
| // * specific language governing permissions and limitations under the License. * |
| // *************************************************************************************************************************** |
| package org.apache.juneau.config.store; |
| |
| import java.io.*; |
| import java.util.*; |
| import java.util.concurrent.*; |
| |
| import org.apache.juneau.*; |
| import org.apache.juneau.annotation.*; |
| import org.apache.juneau.config.internal.*; |
| |
| /** |
| * Represents a storage location for configuration files. |
| * |
| * <p> |
| * Content stores require two methods to be implemented: |
| * <ul class='javatree'> |
| * <li class='jm'>{@link #read(String)} - Retrieve a config file. |
| * <li class='jm'>{@link #write(String,String,String)} - ConfigStore a config file. |
| * </ul> |
| */ |
| @ConfigurableContext |
| public abstract class ConfigStore extends Context implements Closeable { |
| |
| //------------------------------------------------------------------------------------------------------------------- |
| // Configurable properties |
| //------------------------------------------------------------------------------------------------------------------- |
| |
| static final String PREFIX = "ConfigStore"; |
| |
| //------------------------------------------------------------------------------------------------------------------- |
| // Instance |
| //------------------------------------------------------------------------------------------------------------------- |
| |
| private final ConcurrentHashMap<String,Set<ConfigStoreListener>> listeners = new ConcurrentHashMap<>(); |
| private final ConcurrentHashMap<String,ConfigMap> configMaps = new ConcurrentHashMap<>(); |
| |
| /** |
| * Constructor. |
| * |
| * @param ps The settings for this content store. |
| */ |
| protected ConfigStore(PropertyStore ps) { |
| super(ps, false); |
| } |
| |
| /** |
| * Returns the contents of the configuration file. |
| * |
| * @param name The config file name. |
| * @return |
| * The contents of the configuration file. |
| * <br>A blank string if the config does not exist. |
| * <br>Never <jk>null</jk>. |
| * @throws IOException Thrown by underlying stream. |
| */ |
| public abstract String read(String name) throws IOException; |
| |
| /** |
| * Saves the contents of the configuration file if the underlying storage hasn't been modified. |
| * |
| * @param name The config file name. |
| * @param expectedContents The expected contents of the file. |
| * @param newContents The new contents. |
| * @return |
| * If <jk>null</jk>, then we successfully stored the contents of the file. |
| * <br>Otherwise the contents of the file have changed and we return the new contents of the file. |
| * @throws IOException Thrown by underlying stream. |
| */ |
| public abstract String write(String name, String expectedContents, String newContents) throws IOException; |
| |
| /** |
| * Checks whether the configuration with the specified name exists in this store. |
| * |
| * @param name The config name. |
| * @return <jk>true</jk> if the configuration with the specified name exists in this store. |
| */ |
| public abstract boolean exists(String name); |
| |
| /** |
| * Registers a new listener on this store. |
| * |
| * @param name The configuration name to listen for. |
| * @param l The new listener. |
| * @return This object (for method chaining). |
| */ |
| public synchronized ConfigStore register(String name, ConfigStoreListener l) { |
| name = resolveName(name); |
| Set<ConfigStoreListener> s = listeners.get(name); |
| if (s == null) { |
| s = Collections.synchronizedSet(Collections.newSetFromMap(new IdentityHashMap<ConfigStoreListener,Boolean>())); |
| listeners.put(name, s); |
| } |
| s.add(l); |
| return this; |
| } |
| |
| /** |
| * Unregisters a listener from this store. |
| * |
| * @param name The configuration name to listen for. |
| * @param l The listener to unregister. |
| * @return This object (for method chaining). |
| */ |
| public synchronized ConfigStore unregister(String name, ConfigStoreListener l) { |
| name = resolveName(name); |
| Set<ConfigStoreListener> s = listeners.get(name); |
| if (s != null) |
| s.remove(l); |
| return this; |
| } |
| |
| /** |
| * Returns a map file containing the parsed contents of a configuration. |
| * |
| * @param name The configuration name. |
| * @return |
| * The parsed configuration. |
| * <br>Never <jk>null</jk>. |
| * @throws IOException Thrown by underlying stream. |
| */ |
| public synchronized ConfigMap getMap(String name) throws IOException { |
| name = resolveName(name); |
| ConfigMap cm = configMaps.get(name); |
| if (cm != null) |
| return cm; |
| cm = new ConfigMap(this, name); |
| ConfigMap cm2 = configMaps.putIfAbsent(name, cm); |
| if (cm2 != null) |
| return cm2; |
| register(name, cm); |
| return cm; |
| } |
| |
| /** |
| * Called when the physical contents of a config file have changed. |
| * |
| * <p> |
| * Triggers calls to {@link ConfigStoreListener#onChange(String)} on all registered listeners. |
| * |
| * @param name The config name (e.g. the filename without the extension). |
| * @param contents The new contents. |
| * @return This object (for method chaining). |
| */ |
| public synchronized ConfigStore update(String name, String contents) { |
| name = resolveName(name); |
| Set<ConfigStoreListener> s = listeners.get(name); |
| if (s != null) |
| for (ConfigStoreListener l : listeners.get(name)) |
| l.onChange(contents); |
| return this; |
| } |
| |
| /** |
| * Convenience method for updating the contents of a file with lines. |
| * |
| * @param name The config name (e.g. the filename without the extension). |
| * @param contentLines The new contents. |
| * @return This object (for method chaining). |
| */ |
| public synchronized ConfigStore update(String name, String...contentLines) { |
| name = resolveName(name); |
| StringBuilder sb = new StringBuilder(); |
| for (String l : contentLines) |
| sb.append(l).append('\n'); |
| return update(name, sb.toString()); |
| } |
| |
| /** |
| * Subclasses can override this method to convert config names to internal forms. |
| * |
| * <p> |
| * For example, the {@link ConfigFileStore} class can take in both <js>"MyConfig"</js> and <js>"MyConfig.cfg"</js> |
| * as names that both resolve to <js>"MyConfig.cfg"</js>. |
| * |
| * @param name The name to resolve. |
| * @return The resolved name. |
| */ |
| protected String resolveName(String name) { |
| return name; |
| } |
| |
| /** |
| * Unused. |
| */ |
| @Override /* Context */ |
| public final Session createSession(SessionArgs args) { |
| throw new NoSuchMethodError(); |
| } |
| |
| /** |
| * Unused. |
| */ |
| @Override /* Context */ |
| public final SessionArgs createDefaultSessionArgs() { |
| throw new NoSuchMethodError(); |
| } |
| |
| //----------------------------------------------------------------------------------------------------------------- |
| // Other methods. |
| //----------------------------------------------------------------------------------------------------------------- |
| |
| @Override /* Context */ |
| public ObjectMap toMap() { |
| return super.toMap() |
| .append("ConfigStore", new DefaultFilteringObjectMap() |
| ); |
| } |
| } |