ConfigurationNodePointer.java
/*
* 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.tree.xpath;
import java.util.Locale;
import org.apache.commons.configuration2.tree.NodeHandler;
import org.apache.commons.jxpath.ri.Compiler;
import org.apache.commons.jxpath.ri.QName;
import org.apache.commons.jxpath.ri.compiler.NodeTest;
import org.apache.commons.jxpath.ri.compiler.NodeTypeTest;
import org.apache.commons.jxpath.ri.model.NodeIterator;
import org.apache.commons.jxpath.ri.model.NodePointer;
/**
* <p>
* A specific {@code NodePointer} implementation for configuration nodes.
* </p>
* <p>
* This is needed for queries using JXPath.
* </p>
*
* @since 1.3
* @param <T> the type of the nodes this pointer deals with
*/
final class ConfigurationNodePointer<T> extends NodePointer {
/**
* The serial version UID.
*/
private static final long serialVersionUID = -1087475639680007713L;
/** The node handler. */
private final NodeHandler<T> handler;
/** Stores the associated node. */
private final T node;
/**
* Creates a new instance of {@code ConfigurationNodePointer} and initializes it with its parent pointer.
*
* @param parent the parent pointer
* @param node the associated node
* @param handler the {@code NodeHandler}
*/
public ConfigurationNodePointer(final ConfigurationNodePointer<T> parent, final T node, final NodeHandler<T> handler) {
super(parent);
this.node = node;
this.handler = handler;
}
/**
* Creates a new instance of {@code ConfigurationNodePointer} pointing to the specified node.
*
* @param node the wrapped node
* @param locale the locale
* @param handler the {@code NodeHandler}
*/
public ConfigurationNodePointer(final T node, final Locale locale, final NodeHandler<T> handler) {
super(null, locale);
this.node = node;
this.handler = handler;
}
/**
* Returns an iterator for the attributes that match the given name.
*
* @param name the attribute name
* @return the iterator for the attributes
*/
@Override
public NodeIterator attributeIterator(final QName name) {
return new ConfigurationNodeIteratorAttribute<>(this, name);
}
/**
* Casts the given child pointer to a node pointer of this type. This is a bit dangerous. However, in a typical setup,
* child node pointers can only be created by this instance which ensures that they are of the correct type. Therefore,
* this cast is safe.
*
* @param p the {@code NodePointer} to cast
* @return the resulting {@code ConfigurationNodePointer}
*/
private ConfigurationNodePointer<T> castPointer(final NodePointer p) {
@SuppressWarnings("unchecked") // see method comment
final ConfigurationNodePointer<T> result = (ConfigurationNodePointer<T>) p;
return result;
}
/**
* Returns an iterator for the children of this pointer that match the given test object.
*
* @param test the test object
* @param reverse the reverse flag
* @param startWith the start value of the iteration
*/
@Override
public NodeIterator childIterator(final NodeTest test, final boolean reverse, final NodePointer startWith) {
return new ConfigurationNodeIteratorChildren<>(this, test, reverse, castPointer(startWith));
}
/**
* Compares two child node pointers.
*
* @param pointer1 one pointer
* @param pointer2 another pointer
* @return a flag, which pointer should be sorted first
*/
@Override
public int compareChildNodePointers(final NodePointer pointer1, final NodePointer pointer2) {
final Object node1 = pointer1.getBaseValue();
final Object node2 = pointer2.getBaseValue();
// sort based on the occurrence in the sub node list
for (final T child : getNodeHandler().getChildren(node)) {
if (child == node1) {
return -1;
}
if (child == node2) {
return 1;
}
}
return 0; // should not happen
}
/**
* Gets this node's base value. This is the associated configuration node.
*
* @return the base value
*/
@Override
public Object getBaseValue() {
return node;
}
/**
* Gets the wrapped configuration node.
*
* @return the wrapped node
*/
public T getConfigurationNode() {
return node;
}
/**
* Gets the immediate node. This is the associated configuration node.
*
* @return the immediate node
*/
@Override
public Object getImmediateNode() {
return node;
}
/**
* Gets this node's length. This is always 1.
*
* @return the node's length
*/
@Override
public int getLength() {
return 1;
}
/**
* Gets this node's name.
*
* @return the name
*/
@Override
public QName getName() {
return new QName(null, getNodeHandler().nodeName(node));
}
/**
* Gets the {@code NodeHandler} used by this instance.
*
* @return the {@code NodeHandler}
*/
public NodeHandler<T> getNodeHandler() {
return handler;
}
/**
* Gets the value of this node.
*
* @return the represented node's value
*/
@Override
public Object getValue() {
return getNodeHandler().getValue(node);
}
/**
* Checks whether this node pointer refers to an attribute node. This is not the case.
*
* @return the attribute flag
*/
@Override
public boolean isAttribute() {
return false;
}
/**
* Returns a flag if this node is a collection. This is not the case.
*
* @return the collection flag
*/
@Override
public boolean isCollection() {
return false;
}
/**
* Returns a flag whether this node is a leaf. This is the case if there are no child nodes.
*
* @return a flag if this node is a leaf
*/
@Override
public boolean isLeaf() {
return getNodeHandler().getChildrenCount(node, null) < 1;
}
/**
* Sets the value of this node. This is not supported, so always an exception is thrown.
*
* @param value the new value
*/
@Override
public void setValue(final Object value) {
throw new UnsupportedOperationException("Node value cannot be set!");
}
/**
* Tests if this node matches the given test. Configuration nodes are text nodes, too because they can contain a value.
*
* @param test the test object
* @return a flag if this node corresponds to the test
*/
@Override
public boolean testNode(final NodeTest test) {
if (test instanceof NodeTypeTest && ((NodeTypeTest) test).getNodeType() == Compiler.NODE_TYPE_TEXT) {
return true;
}
return super.testNode(test);
}
}