| /* |
| * 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.commons.configuration2; |
| |
| import java.util.Collection; |
| import java.util.List; |
| |
| import org.apache.commons.configuration2.tree.ExpressionEngine; |
| import org.apache.commons.configuration2.tree.NodeModelSupport; |
| |
| /** |
| * <p> |
| * An interface for mutable hierarchical configurations. |
| * </p> |
| * <p> |
| * This interface introduces methods for manipulating tree-like structured |
| * configuration sources. Also, all methods defined by the {@code Configuration} |
| * interface are available. |
| * </p> |
| * <p> |
| * This interface does not make any assumptions about the concrete type of nodes |
| * used by an implementation; this is reflected by a generic type parameter. |
| * Concrete implementations may therefore define their own hierarchical |
| * structures. |
| * </p> |
| * |
| * @version $Id$ |
| * @since 2.0 |
| * @param <T> the type of the nodes used by this hierarchical configuration |
| */ |
| public interface HierarchicalConfiguration<T> |
| extends Configuration, ImmutableHierarchicalConfiguration, NodeModelSupport<T> |
| { |
| /** |
| * Sets the expression engine to be used by this configuration. All property |
| * keys this configuration has to deal with will be interpreted by this |
| * engine. |
| * |
| * @param expressionEngine the new expression engine; can be <b>null</b>, |
| * then the default expression engine will be used |
| */ |
| void setExpressionEngine(ExpressionEngine expressionEngine); |
| |
| /** |
| * Adds a collection of nodes at the specified position of the configuration |
| * tree. This method works similar to {@code addProperty()}, but |
| * instead of a single property a whole collection of nodes can be added - |
| * and thus complete configuration sub trees. E.g. with this method it is |
| * possible to add parts of another {@code BaseHierarchicalConfiguration} |
| * object to this object. If the passed in key refers to |
| * an existing and unique node, the new nodes are added to this node. |
| * Otherwise a new node will be created at the specified position in the |
| * hierarchy. |
| * |
| * @param key the key where the nodes are to be added; can be <b>null </b>, |
| * then they are added to the root node |
| * @param nodes a collection with the {@code Node} objects to be |
| * added |
| */ |
| void addNodes(String key, Collection<? extends T> nodes); |
| |
| /** |
| * <p> |
| * Returns a hierarchical sub configuration object that wraps the |
| * configuration node specified by the given key. This method provides an |
| * easy means of accessing sub trees of a hierarchical configuration. In the |
| * returned configuration the sub tree can directly be accessed, it becomes |
| * the root node of this configuration. Because of this the passed in key |
| * must select exactly one configuration node; otherwise an |
| * {@code IllegalArgumentException} will be thrown. |
| * </p> |
| * <p> |
| * The difference between this method and the |
| * {@link #subset(String)} method is that |
| * {@code subset()} supports arbitrary subsets of configuration nodes |
| * while {@code configurationAt()} only returns a single sub tree. |
| * Please refer to the documentation of the |
| * {@link SubnodeConfiguration} class to obtain further information |
| * about sub configurations and when they should be used. |
| * </p> |
| * <p> |
| * With the {@code supportUpdate} flag the behavior of the returned |
| * sub configuration regarding updates of its parent |
| * configuration can be determined. If set to <b>false</b>, the configurations |
| * return on independent nodes structures. So changes made on one configuration |
| * cannot be seen by the other one. A value of <b>true</b> in contrast creates |
| * a direct connection between both configurations - they are then using the |
| * same underlying data structures as much as possible. There are however changes |
| * which break this connection; for instance, if the sub tree the sub configuration |
| * belongs to is completely removed from the parent configuration. If such a |
| * change happens, the sub configuration becomes detached from its parent. |
| * It can still be used in a normal way, but changes on it are not reflected |
| * by the parent and vice verse. Also, it is not possible to reattach a once |
| * detached sub configuration. |
| * </p> |
| * |
| * @param key the key that selects the sub tree |
| * @param supportUpdates a flag whether the returned sub configuration |
| * should be directly connected to its parent |
| * @return a hierarchical configuration that contains this sub tree |
| * @see SubnodeConfiguration |
| */ |
| HierarchicalConfiguration<T> configurationAt(String key, boolean supportUpdates); |
| |
| /** |
| * Returns a hierarchical subnode configuration for the node specified by |
| * the given key. This is a short form for {@code configurationAt(key, |
| * <b>false</b>)}. |
| * |
| * @param key the key that selects the sub tree |
| * @return a hierarchical configuration that contains this sub tree |
| * @see SubnodeConfiguration |
| */ |
| HierarchicalConfiguration<T> configurationAt(String key); |
| |
| /** |
| * Returns a list of sub configurations for all configuration nodes selected |
| * by the given key. This method will evaluate the passed in key (using the |
| * current {@code ExpressionEngine}) and then create a sub configuration for |
| * each returned node (like {@link #configurationAt(String)} ). This is |
| * especially useful when dealing with list-like structures. As an example |
| * consider the configuration that contains data about database tables and |
| * their fields. If you need access to all fields of a certain table, you |
| * can simply do |
| * |
| * <pre> |
| * List fields = config.configurationsAt("tables.table(0).fields.field"); |
| * for(Iterator it = fields.iterator(); it.hasNext();) |
| * { |
| * BaseHierarchicalConfiguration sub = (BaseHierarchicalConfiguration) it.next(); |
| * // now the children and attributes of the field node can be |
| * // directly accessed |
| * String fieldName = sub.getString("name"); |
| * String fieldType = sub.getString("type"); |
| * ... |
| * </pre> |
| * |
| * The configuration objects returned are <strong>not</strong> connected to |
| * the parent configuration. |
| * |
| * @param key the key for selecting the desired nodes |
| * @return a list with hierarchical configuration objects; each |
| * configuration represents one of the nodes selected by the passed |
| * in key |
| */ |
| List<HierarchicalConfiguration<T>> configurationsAt(String key); |
| |
| /** |
| * Returns a list of sub configurations for all configuration nodes selected |
| * by the given key allowing the caller to specify the |
| * {@code supportUpdates} flag. This method works like |
| * {@link #configurationsAt(String)}, but with the additional boolean |
| * parameter it can be specified whether the returned configurations react |
| * on updates of the parent configuration. |
| * |
| * @param key the key for selecting the desired nodes |
| * @param supportUpdates a flag whether the returned sub configuration |
| * should be directly connected to its parent |
| * @return a list with hierarchical configuration objects; each |
| * configuration represents one of the nodes selected by the passed |
| * in key |
| * @see #configurationsAt(String, boolean) |
| */ |
| List<HierarchicalConfiguration<T>> configurationsAt(String key, |
| boolean supportUpdates); |
| |
| /** |
| * Returns a list with sub configurations for all child nodes of the node |
| * selected by the given key. This method works like |
| * {@link #immutableChildConfigurationsAt(String)}, but returns a list with |
| * mutable configuration objects. The configuration objects returned are |
| * <strong>not</strong> connected to the parent configuration. |
| * |
| * @param key the key for selecting the desired parent node |
| * @return a collection with {@code HierarchicalConfiguration} objects for all |
| * child nodes of the selected parent node |
| */ |
| List<HierarchicalConfiguration<T>> childConfigurationsAt(String key); |
| |
| /** |
| * Returns a list with sub configurations for all child nodes of the node |
| * selected by the given key allowing the caller to specify the |
| * {@code supportUpdates} flag. |
| * |
| * @param key the key for selecting the desired parent node |
| * @param supportUpdates a flag whether the returned sub configuration |
| * should be directly connected to its parent |
| * @return a collection with {@code HierarchicalConfiguration} objects for |
| * all child nodes of the selected parent node |
| */ |
| List<HierarchicalConfiguration<T>> childConfigurationsAt(String key, |
| boolean supportUpdates); |
| |
| /** |
| * Removes all values of the property with the given name and of keys that |
| * start with this name. So if there is a property with the key |
| * "foo" and a property with the key "foo.bar", a call |
| * of {@code clearTree("foo")} would remove both properties. |
| * |
| * @param key the key of the property to be removed |
| */ |
| void clearTree(String key); |
| } |
