org.apache.commons.configuration2.tree.xpath.ConfigurationAttributePointer Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of commons-configuration2 Show documentation
Show all versions of commons-configuration2 Show documentation
Tools to assist in the reading of configuration/preferences files in
various formats
/*
* 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 org.apache.commons.configuration2.tree.NodeHandler;
import org.apache.commons.configuration2.tree.QueryResult;
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.NodePointer;
/**
*
* A specialized {@code NodePointer} implementation for the attributes of
* a configuration node.
*
*
* @since 2.0
* @param the type of the nodes this pointer deals with
*/
class ConfigurationAttributePointer extends NodePointer
{
/**
* The serial version UID.
*/
private static final long serialVersionUID = 5504551041716043748L;
/** Stores information about the represented attribute. */
private final QueryResult attributeResult;
/**
* Creates a new instance of {@code ConfigurationAttributePointer}.
*
* @param parent the parent node pointer
* @param attrName the name of the managed attribute
*/
public ConfigurationAttributePointer(final ConfigurationNodePointer parent,
final String attrName)
{
super(parent);
attributeResult =
QueryResult.createAttributeResult(
parent.getConfigurationNode(), attrName);
}
/**
* Returns a reference to the parent node pointer.
*
* @return the parent pointer
*/
public ConfigurationNodePointer getParentPointer()
{
// safe to cast because the constructor only expects pointers of this
// type
@SuppressWarnings("unchecked")
final
ConfigurationNodePointer configurationNodePointer =
(ConfigurationNodePointer) getParent();
return configurationNodePointer;
}
/**
* Compares two child node pointers. Attributes do not have any children, so
* this is just a dummy implementation.
*
* @param p1 the first pointer
* @param p2 the second pointer
* @return the order of these pointers
*/
@Override
public int compareChildNodePointers(final NodePointer p1, final NodePointer p2)
{
return 0;
}
/**
* Returns the base value. We return the value.
*
* @return the base value
*/
@Override
public Object getBaseValue()
{
return getValue();
}
/**
* Returns the immediate node. This is actually a {@link QueryResult}
* object describing the represented attribute.
*
* @return the immediate node
*/
@Override
public Object getImmediateNode()
{
return attributeResult;
}
/**
* Returns the length of the represented node. This is always 1.
*
* @return the length
*/
@Override
public int getLength()
{
return 1;
}
/**
* Returns the name of this node. This is the attribute name.
*
* @return the name of this node
*/
@Override
public QName getName()
{
return new QName(null, attributeResult.getAttributeName());
}
/**
* Returns a flag whether the represented node is a collection. This is not
* the case.
*
* @return the collection flag
*/
@Override
public boolean isCollection()
{
return false;
}
/**
* Returns a flag whether the represented node is a leaf. This is the case
* for attributes.
*
* @return the leaf flag
*/
@Override
public boolean isLeaf()
{
return true;
}
/**
* Returns a flag whether this node is an attribute. Of course, this is the
* case.
*
* @return the attribute flag
*/
@Override
public boolean isAttribute()
{
return true;
}
/**
* Returns the value of this node.
*
* @return this node's value
*/
@Override
public Object getValue()
{
return attributeResult.getAttributeValue(getNodeHandler());
}
/**
* Sets the value of this node. This is not supported because the classes of
* the {@code XPathExpressionEngine} are only used for queries. This
* implementation always throws an exception.
*
* @param value the new value
*/
@Override
public void setValue(final Object value)
{
throw new UnsupportedOperationException(
"Updating the value is not supported!");
}
/**
* Tests if this node matches the given test. Attribute 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);
}
/**
* Returns a reference to the current node handler. The handler is obtained
* from the parent pointer.
*
* @return the node handler
*/
private NodeHandler getNodeHandler()
{
return getParentPointer().getNodeHandler();
}
}