| /* |
| * 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.ArrayList; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.Iterator; |
| import java.util.LinkedList; |
| import java.util.List; |
| import java.util.Map; |
| |
| import org.apache.commons.configuration2.event.ConfigurationEvent; |
| import org.apache.commons.configuration2.event.EventListener; |
| import org.apache.commons.configuration2.ex.ConfigurationRuntimeException; |
| import org.apache.commons.configuration2.interpol.ConfigurationInterpolator; |
| import org.apache.commons.configuration2.tree.ConfigurationNodeVisitorAdapter; |
| import org.apache.commons.configuration2.tree.ImmutableNode; |
| import org.apache.commons.configuration2.tree.InMemoryNodeModel; |
| import org.apache.commons.configuration2.tree.InMemoryNodeModelSupport; |
| import org.apache.commons.configuration2.tree.NodeHandler; |
| import org.apache.commons.configuration2.tree.NodeModel; |
| import org.apache.commons.configuration2.tree.NodeSelector; |
| import org.apache.commons.configuration2.tree.NodeTreeWalker; |
| import org.apache.commons.configuration2.tree.QueryResult; |
| import org.apache.commons.configuration2.tree.ReferenceNodeHandler; |
| import org.apache.commons.configuration2.tree.TrackedNodeModel; |
| import org.apache.commons.lang3.ObjectUtils; |
| |
| /** |
| * <p> |
| * A specialized hierarchical configuration implementation that is based on a |
| * structure of {@link ImmutableNode} objects. |
| * </p> |
| * |
| */ |
| public class BaseHierarchicalConfiguration extends AbstractHierarchicalConfiguration<ImmutableNode> |
| implements InMemoryNodeModelSupport |
| { |
| /** A listener for reacting on changes caused by sub configurations. */ |
| private final EventListener<ConfigurationEvent> changeListener; |
| |
| /** |
| * Creates a new instance of {@code BaseHierarchicalConfiguration}. |
| */ |
| public BaseHierarchicalConfiguration() |
| { |
| this((HierarchicalConfiguration<ImmutableNode>) null); |
| } |
| |
| /** |
| * Creates a new instance of {@code BaseHierarchicalConfiguration} and |
| * copies all data contained in the specified configuration into the new |
| * one. |
| * |
| * @param c the configuration that is to be copied (if <b>null</b>, this |
| * constructor will behave like the standard constructor) |
| * @since 1.4 |
| */ |
| public BaseHierarchicalConfiguration(final HierarchicalConfiguration<ImmutableNode> c) |
| { |
| this(createNodeModel(c)); |
| } |
| |
| /** |
| * Creates a new instance of {@code BaseHierarchicalConfiguration} and |
| * initializes it with the given {@code NodeModel}. |
| * |
| * @param model the {@code NodeModel} |
| */ |
| protected BaseHierarchicalConfiguration(final NodeModel<ImmutableNode> model) |
| { |
| super(model); |
| changeListener = createChangeListener(); |
| } |
| |
| /** |
| * {@inheritDoc} This implementation returns the {@code InMemoryNodeModel} |
| * used by this configuration. |
| */ |
| @Override |
| public InMemoryNodeModel getNodeModel() |
| { |
| return (InMemoryNodeModel) super.getNodeModel(); |
| } |
| |
| /** |
| * Creates a new {@code Configuration} object containing all keys |
| * that start with the specified prefix. This implementation will return a |
| * {@code BaseHierarchicalConfiguration} object so that the structure of |
| * the keys will be saved. The nodes selected by the prefix (it is possible |
| * that multiple nodes are selected) are mapped to the root node of the |
| * returned configuration, i.e. their children and attributes will become |
| * children and attributes of the new root node. However, a value of the root |
| * node is only set if exactly one of the selected nodes contain a value (if |
| * multiple nodes have a value, there is simply no way to decide how these |
| * values are merged together). Note that the returned |
| * {@code Configuration} object is not connected to its source |
| * configuration: updates on the source configuration are not reflected in |
| * the subset and vice versa. The returned configuration uses the same |
| * {@code Synchronizer} as this configuration. |
| * |
| * @param prefix the prefix of the keys for the subset |
| * @return a new configuration object representing the selected subset |
| */ |
| @Override |
| public Configuration subset(final String prefix) |
| { |
| beginRead(false); |
| try |
| { |
| final List<QueryResult<ImmutableNode>> results = fetchNodeList(prefix); |
| if (results.isEmpty()) |
| { |
| return new BaseHierarchicalConfiguration(); |
| } |
| |
| final BaseHierarchicalConfiguration parent = this; |
| final BaseHierarchicalConfiguration result = |
| new BaseHierarchicalConfiguration() |
| { |
| // Override interpolate to always interpolate on the parent |
| @Override |
| protected Object interpolate(final Object value) |
| { |
| return parent.interpolate(value); |
| } |
| |
| @Override |
| public ConfigurationInterpolator getInterpolator() |
| { |
| return parent.getInterpolator(); |
| } |
| }; |
| result.getModel().setRootNode(createSubsetRootNode(results)); |
| |
| if (result.isEmpty()) |
| { |
| return new BaseHierarchicalConfiguration(); |
| } |
| result.setSynchronizer(getSynchronizer()); |
| return result; |
| } |
| finally |
| { |
| endRead(); |
| } |
| } |
| |
| /** |
| * Creates a root node for a subset configuration based on the passed in |
| * query results. This method creates a new root node and adds the children |
| * and attributes of all result nodes to it. If only a single node value is |
| * defined, it is assigned as value of the new root node. |
| * |
| * @param results the collection of query results |
| * @return the root node for the subset configuration |
| */ |
| private ImmutableNode createSubsetRootNode( |
| final Collection<QueryResult<ImmutableNode>> results) |
| { |
| final ImmutableNode.Builder builder = new ImmutableNode.Builder(); |
| Object value = null; |
| int valueCount = 0; |
| |
| for (final QueryResult<ImmutableNode> result : results) |
| { |
| if (result.isAttributeResult()) |
| { |
| builder.addAttribute(result.getAttributeName(), |
| result.getAttributeValue(getModel().getNodeHandler())); |
| } |
| else |
| { |
| if (result.getNode().getValue() != null) |
| { |
| value = result.getNode().getValue(); |
| valueCount++; |
| } |
| builder.addChildren(result.getNode().getChildren()); |
| builder.addAttributes(result.getNode().getAttributes()); |
| } |
| } |
| |
| if (valueCount == 1) |
| { |
| builder.value(value); |
| } |
| return builder.create(); |
| } |
| |
| /** |
| * {@inheritDoc} The result of this implementation depends on the |
| * {@code supportUpdates} flag: If it is <b>false</b>, a plain |
| * {@code BaseHierarchicalConfiguration} is returned using the selected node |
| * as root node. This is suitable for read-only access to properties. |
| * Because the configuration returned in this case is not connected to the |
| * parent configuration, updates on properties made by one configuration are |
| * not reflected by the other one. A value of <b>true</b> for this parameter |
| * causes a tracked node to be created, and result is a |
| * {@link SubnodeConfiguration} based on this tracked node. This |
| * configuration is really connected to its parent, so that updated |
| * properties are visible on both. |
| * |
| * @see SubnodeConfiguration |
| * @throws ConfigurationRuntimeException if the key does not select a single |
| * node |
| */ |
| @Override |
| public HierarchicalConfiguration<ImmutableNode> configurationAt(final String key, |
| final boolean supportUpdates) |
| { |
| beginRead(false); |
| try |
| { |
| return supportUpdates ? createConnectedSubConfiguration(key) |
| : createIndependentSubConfiguration(key); |
| } |
| finally |
| { |
| endRead(); |
| } |
| } |
| |
| /** |
| * Returns the {@code InMemoryNodeModel} to be used as parent model for a |
| * new sub configuration. This method is called whenever a sub configuration |
| * is to be created. This base implementation returns the model of this |
| * configuration. Sub classes with different requirements for the parent |
| * models of sub configurations have to override it. |
| * |
| * @return the parent model for a new sub configuration |
| */ |
| protected InMemoryNodeModel getSubConfigurationParentModel() |
| { |
| return (InMemoryNodeModel) getModel(); |
| } |
| |
| /** |
| * Returns the {@code NodeSelector} to be used for a sub configuration based |
| * on the passed in key. This method is called whenever a sub configuration |
| * is to be created. This base implementation returns a new |
| * {@code NodeSelector} initialized with the passed in key. Sub classes may |
| * override this method if they have a different strategy for creating a |
| * selector. |
| * |
| * @param key the key of the sub configuration |
| * @return a {@code NodeSelector} for initializing a sub configuration |
| * @since 2.0 |
| */ |
| protected NodeSelector getSubConfigurationNodeSelector(final String key) |
| { |
| return new NodeSelector(key); |
| } |
| |
| /** |
| * Creates a connected sub configuration based on a selector for a tracked |
| * node. |
| * |
| * @param selector the {@code NodeSelector} |
| * @param parentModelSupport the {@code InMemoryNodeModelSupport} object for |
| * the parent node model |
| * @return the newly created sub configuration |
| * @since 2.0 |
| */ |
| protected SubnodeConfiguration createSubConfigurationForTrackedNode( |
| final NodeSelector selector, final InMemoryNodeModelSupport parentModelSupport) |
| { |
| final SubnodeConfiguration subConfig = |
| new SubnodeConfiguration(this, new TrackedNodeModel( |
| parentModelSupport, selector, true)); |
| initSubConfigurationForThisParent(subConfig); |
| return subConfig; |
| } |
| |
| /** |
| * Initializes a {@code SubnodeConfiguration} object. This method should be |
| * called for each sub configuration created for this configuration. It |
| * ensures that the sub configuration is correctly connected to its parent |
| * instance and that update events are correctly propagated. |
| * |
| * @param subConfig the sub configuration to be initialized |
| * @since 2.0 |
| */ |
| protected void initSubConfigurationForThisParent(final SubnodeConfiguration subConfig) |
| { |
| initSubConfiguration(subConfig); |
| subConfig.addEventListener(ConfigurationEvent.ANY, changeListener); |
| } |
| |
| /** |
| * Creates a sub configuration from the specified key which is connected to |
| * this configuration. This implementation creates a |
| * {@link SubnodeConfiguration} with a tracked node identified by the passed |
| * in key. |
| * |
| * @param key the key of the sub configuration |
| * @return the new sub configuration |
| */ |
| private BaseHierarchicalConfiguration createConnectedSubConfiguration( |
| final String key) |
| { |
| final NodeSelector selector = getSubConfigurationNodeSelector(key); |
| getSubConfigurationParentModel().trackNode(selector, this); |
| return createSubConfigurationForTrackedNode(selector, this); |
| } |
| |
| /** |
| * Creates a list of connected sub configurations based on a passed in list |
| * of node selectors. |
| * |
| * @param parentModelSupport the parent node model support object |
| * @param selectors the list of {@code NodeSelector} objects |
| * @return the list with sub configurations |
| */ |
| private List<HierarchicalConfiguration<ImmutableNode>> createConnectedSubConfigurations( |
| final InMemoryNodeModelSupport parentModelSupport, |
| final Collection<NodeSelector> selectors) |
| { |
| final List<HierarchicalConfiguration<ImmutableNode>> configs = |
| new ArrayList<>( |
| selectors.size()); |
| for (final NodeSelector selector : selectors) |
| { |
| configs.add(createSubConfigurationForTrackedNode(selector, |
| parentModelSupport)); |
| } |
| return configs; |
| } |
| |
| /** |
| * Creates a sub configuration from the specified key which is independent |
| * on this configuration. This means that the sub configuration operates on |
| * a separate node model (although the nodes are initially shared). |
| * |
| * @param key the key of the sub configuration |
| * @return the new sub configuration |
| */ |
| private BaseHierarchicalConfiguration createIndependentSubConfiguration( |
| final String key) |
| { |
| final List<ImmutableNode> targetNodes = fetchFilteredNodeResults(key); |
| final int size = targetNodes.size(); |
| if (size != 1) |
| { |
| throw new ConfigurationRuntimeException( |
| "Passed in key must select exactly one node (found %,d): %s", size, key); |
| } |
| final BaseHierarchicalConfiguration sub = |
| new BaseHierarchicalConfiguration(new InMemoryNodeModel( |
| targetNodes.get(0))); |
| initSubConfiguration(sub); |
| return sub; |
| } |
| |
| /** |
| * Returns an initialized sub configuration for this configuration that is |
| * based on another {@code BaseHierarchicalConfiguration}. Thus, it is |
| * independent from this configuration. |
| * |
| * @param node the root node for the sub configuration |
| * @return the initialized sub configuration |
| */ |
| private BaseHierarchicalConfiguration createIndependentSubConfigurationForNode( |
| final ImmutableNode node) |
| { |
| final BaseHierarchicalConfiguration sub = |
| new BaseHierarchicalConfiguration(new InMemoryNodeModel(node)); |
| initSubConfiguration(sub); |
| return sub; |
| } |
| |
| /** |
| * Executes a query on the specified key and filters it for node results. |
| * |
| * @param key the key |
| * @return the filtered list with result nodes |
| */ |
| private List<ImmutableNode> fetchFilteredNodeResults(final String key) |
| { |
| final NodeHandler<ImmutableNode> handler = getModel().getNodeHandler(); |
| return resolveNodeKey(handler.getRootNode(), key, handler); |
| } |
| |
| /** |
| * {@inheritDoc} This implementation creates a {@code SubnodeConfiguration} |
| * by delegating to {@code configurationAt()}. Then an immutable wrapper |
| * is created and returned. |
| */ |
| @Override |
| public ImmutableHierarchicalConfiguration immutableConfigurationAt( |
| final String key, final boolean supportUpdates) |
| { |
| return ConfigurationUtils.unmodifiableConfiguration(configurationAt( |
| key, supportUpdates)); |
| } |
| |
| /** |
| * {@inheritDoc} This is a short form for {@code configurationAt(key, |
| * <b>false</b>)}. |
| * @throws ConfigurationRuntimeException if the key does not select a single node |
| */ |
| @Override |
| public HierarchicalConfiguration<ImmutableNode> configurationAt(final String key) |
| { |
| return configurationAt(key, false); |
| } |
| |
| /** |
| * {@inheritDoc} This implementation creates a {@code SubnodeConfiguration} |
| * by delegating to {@code configurationAt()}. Then an immutable wrapper |
| * is created and returned. |
| * @throws ConfigurationRuntimeException if the key does not select a single node |
| */ |
| @Override |
| public ImmutableHierarchicalConfiguration immutableConfigurationAt( |
| final String key) |
| { |
| return ConfigurationUtils.unmodifiableConfiguration(configurationAt( |
| key)); |
| } |
| |
| /** |
| * {@inheritDoc} This implementation creates sub configurations in the same |
| * way as described for {@link #configurationAt(String)}. |
| */ |
| @Override |
| public List<HierarchicalConfiguration<ImmutableNode>> configurationsAt( |
| final String key) |
| { |
| List<ImmutableNode> nodes; |
| beginRead(false); |
| try |
| { |
| nodes = fetchFilteredNodeResults(key); |
| } |
| finally |
| { |
| endRead(); |
| } |
| |
| final List<HierarchicalConfiguration<ImmutableNode>> results = |
| new ArrayList<>( |
| nodes.size()); |
| for (final ImmutableNode node : nodes) |
| { |
| final BaseHierarchicalConfiguration sub = |
| createIndependentSubConfigurationForNode(node); |
| results.add(sub); |
| } |
| |
| return results; |
| } |
| |
| /** |
| * {@inheritDoc} This implementation creates tracked nodes for the specified |
| * key. Then sub configurations for these nodes are created and returned. |
| */ |
| @Override |
| public List<HierarchicalConfiguration<ImmutableNode>> configurationsAt( |
| final String key, final boolean supportUpdates) |
| { |
| if (!supportUpdates) |
| { |
| return configurationsAt(key); |
| } |
| |
| InMemoryNodeModel parentModel; |
| beginRead(false); |
| try |
| { |
| parentModel = getSubConfigurationParentModel(); |
| } |
| finally |
| { |
| endRead(); |
| } |
| |
| final Collection<NodeSelector> selectors = |
| parentModel.selectAndTrackNodes(key, this); |
| return createConnectedSubConfigurations(this, selectors); |
| } |
| |
| /** |
| * {@inheritDoc} This implementation first delegates to |
| * {@code configurationsAt()} to create a list of |
| * {@code SubnodeConfiguration} objects. Then for each element of this list |
| * an unmodifiable wrapper is created. |
| */ |
| @Override |
| public List<ImmutableHierarchicalConfiguration> immutableConfigurationsAt( |
| final String key) |
| { |
| return toImmutable(configurationsAt(key)); |
| } |
| |
| /** |
| * {@inheritDoc} This implementation resolves the node(s) selected by the |
| * given key. If not a single node is selected, an empty list is returned. |
| * Otherwise, sub configurations for each child of the node are created. |
| */ |
| @Override |
| public List<HierarchicalConfiguration<ImmutableNode>> childConfigurationsAt( |
| final String key) |
| { |
| List<ImmutableNode> nodes; |
| beginRead(false); |
| try |
| { |
| nodes = fetchFilteredNodeResults(key); |
| } |
| finally |
| { |
| endRead(); |
| } |
| |
| if (nodes.size() != 1) |
| { |
| return Collections.emptyList(); |
| } |
| |
| final ImmutableNode parent = nodes.get(0); |
| final List<HierarchicalConfiguration<ImmutableNode>> subs = |
| new ArrayList<>(parent |
| .getChildren().size()); |
| for (final ImmutableNode node : parent.getChildren()) |
| { |
| subs.add(createIndependentSubConfigurationForNode(node)); |
| } |
| |
| return subs; |
| } |
| |
| /** |
| * {@inheritDoc} This method works like |
| * {@link #childConfigurationsAt(String)}; however, depending on the value |
| * of the {@code supportUpdates} flag, connected sub configurations may be |
| * created. |
| */ |
| @Override |
| public List<HierarchicalConfiguration<ImmutableNode>> childConfigurationsAt( |
| final String key, final boolean supportUpdates) |
| { |
| if (!supportUpdates) |
| { |
| return childConfigurationsAt(key); |
| } |
| |
| final InMemoryNodeModel parentModel = getSubConfigurationParentModel(); |
| return createConnectedSubConfigurations(this, |
| parentModel.trackChildNodes(key, this)); |
| } |
| |
| /** |
| * {@inheritDoc} This implementation first delegates to |
| * {@code childConfigurationsAt()} to create a list of mutable child |
| * configurations. Then a list with immutable wrapper configurations is |
| * created. |
| */ |
| @Override |
| public List<ImmutableHierarchicalConfiguration> immutableChildConfigurationsAt( |
| final String key) |
| { |
| return toImmutable(childConfigurationsAt(key)); |
| } |
| |
| /** |
| * This method is always called when a subnode configuration created from |
| * this configuration has been modified. This implementation transforms the |
| * received event into an event of type {@code SUBNODE_CHANGED} |
| * and notifies the registered listeners. |
| * |
| * @param event the event describing the change |
| * @since 1.5 |
| */ |
| protected void subnodeConfigurationChanged(final ConfigurationEvent event) |
| { |
| fireEvent(ConfigurationEvent.SUBNODE_CHANGED, null, event, event.isBeforeUpdate()); |
| } |
| |
| /** |
| * Initializes properties of a sub configuration. A sub configuration |
| * inherits some settings from its parent, e.g. the expression engine or the |
| * synchronizer. The corresponding values are copied by this method. |
| * |
| * @param sub the sub configuration to be initialized |
| */ |
| private void initSubConfiguration(final BaseHierarchicalConfiguration sub) |
| { |
| sub.setSynchronizer(getSynchronizer()); |
| sub.setExpressionEngine(getExpressionEngine()); |
| sub.setListDelimiterHandler(getListDelimiterHandler()); |
| sub.setThrowExceptionOnMissing(isThrowExceptionOnMissing()); |
| sub.getInterpolator().setParentInterpolator(getInterpolator()); |
| } |
| |
| /** |
| * Creates a listener which reacts on all changes on this configuration or |
| * one of its {@code SubnodeConfiguration} instances. If such a change is |
| * detected, some updates have to be performed. |
| * |
| * @return the newly created change listener |
| */ |
| private EventListener<ConfigurationEvent> createChangeListener() |
| { |
| return this::subnodeConfigurationChanged; |
| } |
| |
| /** |
| * Returns a configuration with the same content as this configuration, but |
| * with all variables replaced by their actual values. This implementation |
| * is specific for hierarchical configurations. It clones the current |
| * configuration and runs a specialized visitor on the clone, which performs |
| * interpolation on the single configuration nodes. |
| * |
| * @return a configuration with all variables interpolated |
| * @since 1.5 |
| */ |
| @Override |
| public Configuration interpolatedConfiguration() |
| { |
| final InterpolatedVisitor visitor = new InterpolatedVisitor(); |
| final NodeHandler<ImmutableNode> handler = getModel().getNodeHandler(); |
| NodeTreeWalker.INSTANCE |
| .walkDFS(handler.getRootNode(), visitor, handler); |
| |
| final BaseHierarchicalConfiguration c = |
| (BaseHierarchicalConfiguration) clone(); |
| c.getNodeModel().setRootNode(visitor.getInterpolatedRoot()); |
| return c; |
| } |
| |
| /** |
| * {@inheritDoc} This implementation creates a new instance of |
| * {@link InMemoryNodeModel}, initialized with this configuration's root |
| * node. This has the effect that although the same nodes are used, the |
| * original and copied configurations are independent on each other. |
| */ |
| @Override |
| protected NodeModel<ImmutableNode> cloneNodeModel() |
| { |
| return new InMemoryNodeModel(getModel().getNodeHandler().getRootNode()); |
| } |
| |
| /** |
| * Creates a list with immutable configurations from the given input list. |
| * |
| * @param subs a list with mutable configurations |
| * @return a list with corresponding immutable configurations |
| */ |
| private static List<ImmutableHierarchicalConfiguration> toImmutable( |
| final List<? extends HierarchicalConfiguration<?>> subs) |
| { |
| final List<ImmutableHierarchicalConfiguration> res = |
| new ArrayList<>(subs.size()); |
| for (final HierarchicalConfiguration<?> sub : subs) |
| { |
| res.add(ConfigurationUtils.unmodifiableConfiguration(sub)); |
| } |
| return res; |
| } |
| |
| /** |
| * Creates the {@code NodeModel} for this configuration based on a passed in |
| * source configuration. This implementation creates an |
| * {@link InMemoryNodeModel}. If the passed in source configuration is |
| * defined, its root node also becomes the root node of this configuration. |
| * Otherwise, a new, empty root node is used. |
| * |
| * @param c the configuration that is to be copied |
| * @return the {@code NodeModel} for the new configuration |
| */ |
| private static NodeModel<ImmutableNode> createNodeModel( |
| final HierarchicalConfiguration<ImmutableNode> c) |
| { |
| final ImmutableNode root = c != null ? obtainRootNode(c) : null; |
| return new InMemoryNodeModel(root); |
| } |
| |
| /** |
| * Obtains the root node from a configuration whose data is to be copied. It |
| * has to be ensured that the synchronizer is called correctly. |
| * |
| * @param c the configuration that is to be copied |
| * @return the root node of this configuration |
| */ |
| private static ImmutableNode obtainRootNode( |
| final HierarchicalConfiguration<ImmutableNode> c) |
| { |
| return c.getNodeModel().getNodeHandler().getRootNode(); |
| } |
| |
| /** |
| * A specialized visitor base class that can be used for storing the tree of |
| * configuration nodes. The basic idea is that each node can be associated |
| * with a reference object. This reference object has a concrete meaning in |
| * a derived class, e.g. an entry in a JNDI context or an XML element. When |
| * the configuration tree is set up, the {@code load()} method is |
| * responsible for setting the reference objects. When the configuration |
| * tree is later modified, new nodes do not have a defined reference object. |
| * This visitor class processes all nodes and finds the ones without a |
| * defined reference object. For those nodes the {@code insert()} |
| * method is called, which must be defined in concrete sub classes. This |
| * method can perform all steps to integrate the new node into the original |
| * structure. |
| */ |
| protected abstract static class BuilderVisitor extends |
| ConfigurationNodeVisitorAdapter<ImmutableNode> |
| { |
| @Override |
| public void visitBeforeChildren(final ImmutableNode node, final NodeHandler<ImmutableNode> handler) |
| { |
| final ReferenceNodeHandler refHandler = (ReferenceNodeHandler) handler; |
| updateNode(node, refHandler); |
| insertNewChildNodes(node, refHandler); |
| } |
| |
| /** |
| * Inserts a new node into the structure constructed by this builder. |
| * This method is called for each node that has been added to the |
| * configuration tree after the configuration has been loaded from its |
| * source. These new nodes have to be inserted into the original |
| * structure. The passed in nodes define the position of the node to be |
| * inserted: its parent and the siblings between to insert. |
| * |
| * @param newNode the node to be inserted |
| * @param parent the parent node |
| * @param sibling1 the sibling after which the node is to be inserted; |
| * can be <b>null</b> if the new node is going to be the first |
| * child node |
| * @param sibling2 the sibling before which the node is to be inserted; |
| * can be <b>null</b> if the new node is going to be the last |
| * child node |
| * @param refHandler the {@code ReferenceNodeHandler} |
| */ |
| protected abstract void insert(ImmutableNode newNode, |
| ImmutableNode parent, ImmutableNode sibling1, |
| ImmutableNode sibling2, ReferenceNodeHandler refHandler); |
| |
| /** |
| * Updates a node that already existed in the original hierarchy. This |
| * method is called for each node that has an assigned reference object. |
| * A concrete implementation should update the reference according to |
| * the node's current value. |
| * |
| * @param node the current node to be processed |
| * @param reference the reference object for this node |
| * @param refHandler the {@code ReferenceNodeHandler} |
| */ |
| protected abstract void update(ImmutableNode node, Object reference, |
| ReferenceNodeHandler refHandler); |
| |
| /** |
| * Updates the value of a node. If this node is associated with a |
| * reference object, the {@code update()} method is called. |
| * |
| * @param node the current node to be processed |
| * @param refHandler the {@code ReferenceNodeHandler} |
| */ |
| private void updateNode(final ImmutableNode node, |
| final ReferenceNodeHandler refHandler) |
| { |
| final Object reference = refHandler.getReference(node); |
| if (reference != null) |
| { |
| update(node, reference, refHandler); |
| } |
| } |
| |
| /** |
| * Inserts new children that have been added to the specified node. |
| * |
| * @param node the current node to be processed |
| * @param refHandler the {@code ReferenceNodeHandler} |
| */ |
| private void insertNewChildNodes(final ImmutableNode node, |
| final ReferenceNodeHandler refHandler) |
| { |
| final Collection<ImmutableNode> subNodes = |
| new LinkedList<>(refHandler.getChildren(node)); |
| final Iterator<ImmutableNode> children = subNodes.iterator(); |
| ImmutableNode sibling1; |
| ImmutableNode nd = null; |
| |
| while (children.hasNext()) |
| { |
| // find the next new node |
| do |
| { |
| sibling1 = nd; |
| nd = children.next(); |
| } while (refHandler.getReference(nd) != null |
| && children.hasNext()); |
| |
| if (refHandler.getReference(nd) == null) |
| { |
| // find all following new nodes |
| final List<ImmutableNode> newNodes = |
| new LinkedList<>(); |
| newNodes.add(nd); |
| while (children.hasNext()) |
| { |
| nd = children.next(); |
| if (refHandler.getReference(nd) == null) |
| { |
| newNodes.add(nd); |
| } |
| else |
| { |
| break; |
| } |
| } |
| |
| // Insert all new nodes |
| final ImmutableNode sibling2 = |
| refHandler.getReference(nd) == null ? null : nd; |
| for (final ImmutableNode insertNode : newNodes) |
| { |
| if (refHandler.getReference(insertNode) == null) |
| { |
| insert(insertNode, node, sibling1, sibling2, |
| refHandler); |
| sibling1 = insertNode; |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| /** |
| * A specialized visitor implementation which constructs the root node of a |
| * configuration with all variables replaced by their interpolated values. |
| */ |
| private class InterpolatedVisitor extends |
| ConfigurationNodeVisitorAdapter<ImmutableNode> |
| { |
| /** A stack for managing node builder instances. */ |
| private final List<ImmutableNode.Builder> builderStack; |
| |
| /** The resulting root node. */ |
| private ImmutableNode interpolatedRoot; |
| |
| /** |
| * Creates a new instance of {@code InterpolatedVisitor}. |
| */ |
| public InterpolatedVisitor() |
| { |
| builderStack = new LinkedList<>(); |
| } |
| |
| /** |
| * Returns the result of this builder: the root node of the interpolated |
| * nodes hierarchy. |
| * |
| * @return the resulting root node |
| */ |
| public ImmutableNode getInterpolatedRoot() |
| { |
| return interpolatedRoot; |
| } |
| |
| @Override |
| public void visitBeforeChildren(final ImmutableNode node, |
| final NodeHandler<ImmutableNode> handler) |
| { |
| if (isLeafNode(node, handler)) |
| { |
| handleLeafNode(node, handler); |
| } |
| else |
| { |
| final ImmutableNode.Builder builder = |
| new ImmutableNode.Builder(handler.getChildrenCount( |
| node, null)) |
| .name(handler.nodeName(node)) |
| .value(interpolate(handler.getValue(node))) |
| .addAttributes( |
| interpolateAttributes(node, handler)); |
| push(builder); |
| } |
| } |
| |
| @Override |
| public void visitAfterChildren(final ImmutableNode node, |
| final NodeHandler<ImmutableNode> handler) |
| { |
| if (!isLeafNode(node, handler)) |
| { |
| final ImmutableNode newNode = pop().create(); |
| storeInterpolatedNode(newNode); |
| } |
| } |
| |
| /** |
| * Pushes a new builder on the stack. |
| * |
| * @param builder the builder |
| */ |
| private void push(final ImmutableNode.Builder builder) |
| { |
| builderStack.add(0, builder); |
| } |
| |
| /** |
| * Pops the top-level element from the stack. |
| * |
| * @return the element popped from the stack |
| */ |
| private ImmutableNode.Builder pop() |
| { |
| return builderStack.remove(0); |
| } |
| |
| /** |
| * Returns the top-level element from the stack without removing it. |
| * |
| * @return the top-level element from the stack |
| */ |
| private ImmutableNode.Builder peek() |
| { |
| return builderStack.get(0); |
| } |
| |
| /** |
| * Returns a flag whether the given node is a leaf. This is the case if |
| * it does not have children. |
| * |
| * @param node the node in question |
| * @param handler the {@code NodeHandler} |
| * @return a flag whether this is a leaf node |
| */ |
| private boolean isLeafNode(final ImmutableNode node, |
| final NodeHandler<ImmutableNode> handler) |
| { |
| return handler.getChildren(node).isEmpty(); |
| } |
| |
| /** |
| * Handles interpolation for a node with no children. If interpolation |
| * does not change this node, it is copied as is to the resulting |
| * structure. Otherwise, a new node is created with the interpolated |
| * values. |
| * |
| * @param node the current node to be processed |
| * @param handler the {@code NodeHandler} |
| */ |
| private void handleLeafNode(final ImmutableNode node, |
| final NodeHandler<ImmutableNode> handler) |
| { |
| final Object value = interpolate(node.getValue()); |
| final Map<String, Object> interpolatedAttributes = |
| new HashMap<>(); |
| final boolean attributeChanged = |
| interpolateAttributes(node, handler, interpolatedAttributes); |
| final ImmutableNode newNode = |
| valueChanged(value, handler.getValue(node)) || attributeChanged ? new ImmutableNode.Builder() |
| .name(handler.nodeName(node)).value(value) |
| .addAttributes(interpolatedAttributes).create() |
| : node; |
| storeInterpolatedNode(newNode); |
| } |
| |
| /** |
| * Stores a processed node. Per default, the node is added to the |
| * current builder on the stack. If no such builder exists, this is the |
| * result node. |
| * |
| * @param node the node to be stored |
| */ |
| private void storeInterpolatedNode(final ImmutableNode node) |
| { |
| if (builderStack.isEmpty()) |
| { |
| interpolatedRoot = node; |
| } |
| else |
| { |
| peek().addChild(node); |
| } |
| } |
| |
| /** |
| * Populates a map with interpolated attributes of the passed in node. |
| * |
| * @param node the current node to be processed |
| * @param handler the {@code NodeHandler} |
| * @param interpolatedAttributes a map for storing the results |
| * @return a flag whether an attribute value was changed by |
| * interpolation |
| */ |
| private boolean interpolateAttributes(final ImmutableNode node, |
| final NodeHandler<ImmutableNode> handler, |
| final Map<String, Object> interpolatedAttributes) |
| { |
| boolean attributeChanged = false; |
| for (final String attr : handler.getAttributes(node)) |
| { |
| final Object attrValue = |
| interpolate(handler.getAttributeValue(node, attr)); |
| if (valueChanged(attrValue, |
| handler.getAttributeValue(node, attr))) |
| { |
| attributeChanged = true; |
| } |
| interpolatedAttributes.put(attr, attrValue); |
| } |
| return attributeChanged; |
| } |
| |
| /** |
| * Returns a map with interpolated attributes of the passed in node. |
| * |
| * @param node the current node to be processed |
| * @param handler the {@code NodeHandler} |
| * @return the map with interpolated attributes |
| */ |
| private Map<String, Object> interpolateAttributes(final ImmutableNode node, |
| final NodeHandler<ImmutableNode> handler) |
| { |
| final Map<String, Object> attributes = new HashMap<>(); |
| interpolateAttributes(node, handler, attributes); |
| return attributes; |
| } |
| |
| /** |
| * Tests whether a value is changed because of interpolation. |
| * |
| * @param interpolatedValue the interpolated value |
| * @param value the original value |
| * @return a flag whether the value was changed |
| */ |
| private boolean valueChanged(final Object interpolatedValue, final Object value) |
| { |
| return ObjectUtils.notEqual(interpolatedValue, value); |
| } |
| } |
| } |
