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apache/commons-configuration/HEAD/./src/main/java/org/apache/commons/configuration2/XMLConfiguration.java
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/*
* 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
*
* https://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.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.io.StringReader;
import java.io.StringWriter;
import java.io.Writer;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.apache.commons.configuration2.convert.ListDelimiterHandler;
import org.apache.commons.configuration2.ex.ConfigurationException;
import org.apache.commons.configuration2.io.ConfigurationLogger;
import org.apache.commons.configuration2.io.FileLocator;
import org.apache.commons.configuration2.io.FileLocatorAware;
import org.apache.commons.configuration2.io.InputStreamSupport;
import org.apache.commons.configuration2.resolver.DefaultEntityResolver;
import org.apache.commons.configuration2.tree.ImmutableNode;
import org.apache.commons.configuration2.tree.NodeTreeWalker;
import org.apache.commons.configuration2.tree.ReferenceNodeHandler;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.mutable.MutableObject;
import org.w3c.dom.Attr;
import org.w3c.dom.CDATASection;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.helpers.DefaultHandler;
/**
* <p>
* A specialized hierarchical configuration class that is able to parse XML documents.
* </p>
* <p>
* The parsed document will be stored keeping its structure. The class also tries to preserve as much information from
* the loaded XML document as possible, including comments and processing instructions. These will be contained in
* documents created by the {@code save()} methods, too.
* </p>
* <p>
* Like other file based configuration classes this class maintains the name and path to the loaded configuration file.
* These properties can be altered using several setter methods, but they are not modified by {@code save()} and
* {@code load()} methods. If XML documents contain relative paths to other documents (for example to a DTD), these references
* are resolved based on the path set for this configuration.
* </p>
* <p>
* By inheriting from {@link AbstractConfiguration} this class provides some extended functionality, for example interpolation
* of property values. Like in {@link PropertiesConfiguration} property values can contain delimiter characters (the
* comma ',' per default) and are then split into multiple values. This works for XML attributes and text content of
* elements as well. The delimiter can be escaped by a backslash. As an example consider the following XML fragment:
* </p>
*
* <pre>
* &lt;config&gt;
* &lt;array&gt;10,20,30,40&lt;/array&gt;
* &lt;scalar&gt;3\,1415&lt;/scalar&gt;
* &lt;cite text="To be or not to be\, this is the question!"/&gt;
* &lt;/config&gt;
* </pre>
*
* <p>
* Here the content of the {@code array} element will be split at the commas, so the {@code array} key will be assigned
* 4 values. In the {@code scalar} property and the {@code text} attribute of the {@code cite} element the comma is
* escaped, so that no splitting is performed.
* </p>
* <p>
* The configuration API allows setting multiple values for a single attribute, for example something like the following is
* legal (assuming that the default expression engine is used):
* </p>
*
* <pre>
* XMLConfiguration config = new XMLConfiguration();
* config.addProperty(&quot;test.dir[@name]&quot;, &quot;C:\\Temp\\&quot;);
* config.addProperty(&quot;test.dir[@name]&quot;, &quot;D:\\Data\\&quot;);
* </pre>
*
* <p>
* However, in XML such a constellation is not supported; an attribute can appear only once for a single element.
* Therefore, an attempt to save a configuration which violates this condition will throw an exception.
* </p>
* <p>
* Like other {@code Configuration} implementations, {@code XMLConfiguration} uses a {@link ListDelimiterHandler} object
* for controlling list split operations. Per default, a list delimiter handler object is set which disables this
* feature. XML has a built-in support for complex structures including list properties; therefore, list splitting is
* not that relevant for this configuration type. Nevertheless, by setting an alternative {@code ListDelimiterHandler}
* implementation, this feature can be enabled. It works as for any other concrete {@code Configuration} implementation.
* </p>
* <p>
* Whitespace in the content of XML documents is trimmed per default. In most cases this is desired. However, sometimes
* whitespace is indeed important and should be treated as part of the value of a property as in the following example:
* </p>
*
* <pre>
* &lt;indent&gt; &lt;/indent&gt;
* </pre>
*
* <p>
* Per default the spaces in the {@code indent} element will be trimmed resulting in an empty element. To tell
* {@code XMLConfiguration} that spaces are relevant the {@code xml:space} attribute can be used, which is defined in
* the <a href="https://www.w3.org/TR/REC-xml/#sec-white-space">XML specification</a>. This will look as follows:
* </p>
*
* <pre>
* &lt;indent <strong>xml:space=&quot;preserve&quot;</strong>&gt; &lt;/indent&gt;
* </pre>
*
* <p>
* The value of the {@code indent} property will now contain the spaces.
* </p>
* <p>
* {@code XMLConfiguration} implements the {@link FileBasedConfiguration} interface and thus can be used together with a
* file-based builder to load XML configuration files from various sources like files, URLs, or streams.
* </p>
* <p>
* Like other {@code Configuration} implementations, this class uses a {@code Synchronizer} object to control concurrent
* access. By choosing a suitable implementation of the {@code Synchronizer} interface, an instance can be made
* thread-safe or not. Note that access to most of the properties typically set through a builder is not protected by
* the {@code Synchronizer}. The intended usage is that these properties are set once at construction time through the
* builder and after that remain constant. If you wish to change such properties during life time of an instance, you
* have to use the {@code lock()} and {@code unlock()} methods manually to ensure that other threads see your changes.
* </p>
* <p>
* More information about the basic functionality supported by {@code XMLConfiguration} can be found at the user's guide
* at <a href="https://commons.apache.org/proper/commons-configuration/userguide/howto_basicfeatures.html"> Basic
* features and AbstractConfiguration</a>. There is also a separate chapter dealing with
* <a href="commons.apache.org/proper/commons-configuration/userguide/howto_xml.html"> XML Configurations</a> in
* special.
* </p>
*
* @since 1.0
*/
public class XMLConfiguration extends BaseHierarchicalConfiguration implements FileBasedConfiguration, FileLocatorAware, InputStreamSupport {
/**
* A concrete {@code BuilderVisitor} that constructs XML documents.
*/
static class XMLBuilderVisitor extends BuilderVisitor {
/**
* Removes all attributes of the given element.
*
* @param elem the element.
*/
private static void clearAttributes(final Element elem) {
final NamedNodeMap attributes = elem.getAttributes();
for (int i = 0; i < attributes.getLength(); i++) {
elem.removeAttribute(attributes.item(i).getNodeName());
}
}
/**
* Returns the only text node of an element for update. This method is called when the element's text changes. Then all
* text nodes except for the first are removed. A reference to the first is returned or <strong>null</strong> if there is no text
* node at all.
*
* @param elem the element.
* @return the first and only text node.
*/
private static Text findTextNodeForUpdate(final Element elem) {
Text result = null;
// Find all Text nodes
final NodeList children = elem.getChildNodes();
final Collection<Node> textNodes = new ArrayList<>();
for (int i = 0; i < children.getLength(); i++) {
final Node nd = children.item(i);
if (nd instanceof Text) {
if (result == null) {
result = (Text) nd;
} else {
textNodes.add(nd);
}
}
}
// We don't want CDATAs
if (result instanceof CDATASection) {
textNodes.add(result);
result = null;
}
// Remove all but the first Text node
textNodes.forEach(elem::removeChild);
return result;
}
/**
* Helper method for updating the values of all attributes of the specified node.
*
* @param node the affected node.
* @param elem the element that is associated with this node.
*/
private static void updateAttributes(final ImmutableNode node, final Element elem) {
if (node != null && elem != null) {
clearAttributes(elem);
node.getAttributes().forEach((k, v) -> {
if (v != null) {
elem.setAttribute(k, v.toString());
}
});
}
}
/** Stores the document to be constructed. */
private final Document document;
/** The element mapping. */
private final Map<Node, Node> elementMapping;
/** A mapping for the references for new nodes. */
private final Map<ImmutableNode, Element> newElements;
/** Stores the list delimiter handler . */
private final ListDelimiterHandler listDelimiterHandler;
/**
* Creates a new instance of {@code XMLBuilderVisitor}.
*
* @param docHelper the document helper
* @param handler the delimiter handler for properties with multiple values
*/
public XMLBuilderVisitor(final XMLDocumentHelper docHelper, final ListDelimiterHandler handler) {
document = docHelper.getDocument();
elementMapping = docHelper.getElementMapping();
listDelimiterHandler = handler;
newElements = new HashMap<>();
}
/**
* Helper method for accessing the element of the specified node.
*
* @param node the node.
* @param refHandler the {@code ReferenceNodeHandler}.
* @return the element of this node.
*/
private Element getElement(final ImmutableNode node, final ReferenceNodeHandler refHandler) {
final Element elementNew = newElements.get(node);
if (elementNew != null) {
return elementNew;
}
// special treatment for root node of the hierarchy
final Object reference = refHandler.getReference(node);
final Node element;
if (reference instanceof XMLDocumentHelper) {
element = ((XMLDocumentHelper) reference).getDocument().getDocumentElement();
} else if (reference instanceof XMLListReference) {
element = ((XMLListReference) reference).getElement();
} else {
element = (Node) reference;
}
return element != null ? (Element) elementMapping.get(element) : document.getDocumentElement();
}
/**
* Updates the current XML document regarding removed nodes. The elements associated with removed nodes are removed from
* the document.
*
* @param refHandler the {@code ReferenceNodeHandler}.
*/
public void handleRemovedNodes(final ReferenceNodeHandler refHandler) {
refHandler.removedReferences().stream().filter(Node.class::isInstance).forEach(ref -> removeReference(elementMapping.get(ref)));
}
/**
* {@inheritDoc} This implementation ensures that the correct XML element is created and inserted between the given
* siblings.
*/
@Override
protected void insert(final ImmutableNode newNode, final ImmutableNode parent, final ImmutableNode sibling1, final ImmutableNode sibling2,
final ReferenceNodeHandler refHandler) {
if (XMLListReference.isListNode(newNode, refHandler)) {
return;
}
final Element elem = document.createElement(newNode.getNodeName());
newElements.put(newNode, elem);
updateAttributes(newNode, elem);
if (newNode.getValue() != null) {
final String txt = String.valueOf(listDelimiterHandler.escape(newNode.getValue(), ListDelimiterHandler.NOOP_TRANSFORMER));
elem.appendChild(document.createTextNode(txt));
}
if (sibling2 == null) {
getElement(parent, refHandler).appendChild(elem);
} else if (sibling1 != null) {
getElement(parent, refHandler).insertBefore(elem, getElement(sibling1, refHandler).getNextSibling());
} else {
getElement(parent, refHandler).insertBefore(elem, getElement(parent, refHandler).getFirstChild());
}
}
/**
* Processes the specified document, updates element values, and adds new nodes to the hierarchy.
*
* @param refHandler the {@code ReferenceNodeHandler}.
*/
public void processDocument(final ReferenceNodeHandler refHandler) {
updateAttributes(refHandler.getRootNode(), document.getDocumentElement());
NodeTreeWalker.INSTANCE.walkDFS(refHandler.getRootNode(), this, refHandler);
}
/**
* Updates the associated XML elements when a node is removed.
*
* @param element the element to be removed.
*/
private void removeReference(final Node element) {
final Node parentElem = element.getParentNode();
if (parentElem != null) {
parentElem.removeChild(element);
}
}
/**
* {@inheritDoc} This implementation determines the XML element associated with the given node. Then this element's
* value and attributes are set accordingly.
*/
@Override
protected void update(final ImmutableNode node, final Object reference, final ReferenceNodeHandler refHandler) {
if (XMLListReference.isListNode(node, refHandler)) {
if (XMLListReference.isFirstListItem(node, refHandler)) {
final String value = XMLListReference.listValue(node, refHandler, listDelimiterHandler);
updateElement(node, refHandler, value);
}
} else {
final Object value = listDelimiterHandler.escape(refHandler.getValue(node), ListDelimiterHandler.NOOP_TRANSFORMER);
updateElement(node, refHandler, value);
}
}
/**
* Updates the node's value if it represents an element node.
*
* @param element the element.
* @param value the new value.
*/
private void updateElement(final Element element, final Object value) {
Text txtNode = findTextNodeForUpdate(element);
if (value == null) {
// remove text
if (txtNode != null) {
element.removeChild(txtNode);
}
} else {
final String newValue = String.valueOf(value);
if (txtNode == null) {
txtNode = document.createTextNode(newValue);
if (element.getFirstChild() != null) {
element.insertBefore(txtNode, element.getFirstChild());
} else {
element.appendChild(txtNode);
}
} else {
txtNode.setNodeValue(newValue);
}
}
}
private void updateElement(final ImmutableNode node, final ReferenceNodeHandler refHandler, final Object value) {
final Element element = getElement(node, refHandler);
updateElement(element, value);
updateAttributes(node, element);
}
}
/** Constant for the default indent size. */
static final int DEFAULT_INDENT_SIZE = 2;
/** Constant for output property name used on a transformer to specify the indent amount. */
static final String INDENT_AMOUNT_PROPERTY = "{http://xml.apache.org/xslt}indent-amount";
/** Constant for the default root element name. */
private static final String DEFAULT_ROOT_NAME = "configuration";
/** Constant for the name of the space attribute. */
private static final String ATTR_SPACE = "xml:space";
/** Constant for an internally used space attribute. */
private static final String ATTR_SPACE_INTERNAL = "config-xml:space";
/** Constant for the xml:space value for preserving whitespace. */
private static final String VALUE_PRESERVE = "preserve";
/** Schema Langauge key for the parser */
private static final String JAXP_SCHEMA_LANGUAGE = "http://java.sun.com/xml/jaxp/properties/schemaLanguage";
/** Schema Language for the parser */
private static final String W3C_XML_SCHEMA = "http://www.w3.org/2001/XMLSchema";
/**
* Determines the number of child elements of this given node with the specified node name.
*
* @param parent the parent node.
* @param name the name in question.
* @return the number of child elements with this name.
*/
private static int countChildElements(final Node parent, final String name) {
final NodeList childNodes = parent.getChildNodes();
int count = 0;
for (int i = 0; i < childNodes.getLength(); i++) {
final Node item = childNodes.item(i);
if (item instanceof Element && name.equals(((Element) item).getTagName())) {
count++;
}
}
return count;
}
/**
* Determines the value of a configuration node. This method mainly checks whether the text value is to be trimmed or
* not. This is normally defined by the trim flag. However, if the node has children and its content is only whitespace,
* then it makes no sense to store any value; this would only scramble layout when the configuration is saved again.
*
* @param content the text content of this node.
* @param hasChildren a flag whether the node has children.
* @param trimFlag the trim flag.
* @return the value to be stored for this node.
*/
private static String determineValue(final String content, final boolean hasChildren, final boolean trimFlag) {
final boolean shouldTrim = trimFlag || StringUtils.isBlank(content) && hasChildren;
return shouldTrim ? content.trim() : content;
}
/**
* Checks whether an element defines a complete list. If this is the case, extended list handling can be applied.
*
* @param element the element to be checked.
* @return a flag whether this is the only element defining the list.
*/
private static boolean isSingleElementList(final Element element) {
final Node parentNode = element.getParentNode();
return countChildElements(parentNode, element.getTagName()) == 1;
}
/**
* Helper method for initializing the attributes of a configuration node from the given XML element.
*
* @param element the current XML element
* @return a map with all attribute values extracted for the current node
*/
private static Map<String, String> processAttributes(final Node element) {
final NamedNodeMap attributes = element.getAttributes();
final Map<String, String> attrmap = new HashMap<>();
for (int i = 0; i < attributes.getLength(); ++i) {
final Node w3cNode = attributes.item(i);
if (w3cNode instanceof Attr) {
final Attr attr = (Attr) w3cNode;
attrmap.put(attr.getName(), attr.getValue());
}
}
return attrmap;
}
/**
* Checks whether the content of the current XML element should be trimmed. This method checks whether a
* {@code xml:space} attribute is present and evaluates its value. See
* <a href="https://www.w3.org/TR/REC-xml/#sec-white-space"> http://www.w3.org/TR/REC-xml/#sec-white-space</a> for more
* details.
*
* @param element the current XML element
* @param currentTrim the current trim flag
* @return a flag whether the content of this element should be trimmed
*/
private static boolean shouldTrim(final Element element, final boolean currentTrim) {
final Attr attr = element.getAttributeNode(ATTR_SPACE);
if (attr == null) {
return currentTrim;
}
return !VALUE_PRESERVE.equals(attr.getValue());
}
/** Stores the name of the root element. */
private String rootElementName;
/** Stores the public ID from the DOCTYPE. */
private String publicID;
/** Stores the system ID from the DOCTYPE. */
private String systemID;
/** Stores the document builder that should be used for loading. */
private DocumentBuilder documentBuilder;
/** Stores a flag whether DTD or Schema validation should be performed. */
private boolean validating;
/** Stores a flag whether DTD or Schema validation is used. */
private boolean schemaValidation;
/** The EntityResolver to use. */
private EntityResolver entityResolver = new DefaultEntityResolver();
/** The current file locator. */
private FileLocator locator;
/**
* Creates a new instance of {@code XMLConfiguration}.
*/
public XMLConfiguration() {
initLogger(new ConfigurationLogger(XMLConfiguration.class));
}
/**
* Creates a new instance of {@code XMLConfiguration} and copies the content of the passed in configuration into this
* object. Note that only the data of the passed in configuration will be copied. If, for instance, the other
* configuration is a {@code XMLConfiguration}, too, things like comments or processing instructions will be lost.
*
* @param c the configuration to copy.
* @since 1.4
*/
public XMLConfiguration(final HierarchicalConfiguration<ImmutableNode> c) {
super(c);
rootElementName = c != null ? c.getRootElementName() : null;
initLogger(new ConfigurationLogger(XMLConfiguration.class));
}
/**
* Helper method for building the internal storage hierarchy. The XML elements are transformed into node objects.
*
* @param node a builder for the current node.
* @param refValue stores the text value of the element.
* @param element the current XML element.
* @param elemRefs a map for assigning references objects to nodes; can be <strong>null</strong>, then reference objects are irrelevant.
* @param trim a flag whether the text content of elements should be trimmed; this controls the whitespace handling.
* @param level the current level in the hierarchy.
* @return a map with all attribute values extracted for the current node; this map also contains the value of the trim flag for this node under the key
* {@value #ATTR_SPACE}.
*/
private Map<String, String> constructHierarchy(final ImmutableNode.Builder node, final MutableObject<String> refValue, final Element element,
final Map<ImmutableNode, Object> elemRefs, final boolean trim, final int level) {
final boolean trimFlag = shouldTrim(element, trim);
final Map<String, String> attributes = processAttributes(element);
attributes.put(ATTR_SPACE_INTERNAL, String.valueOf(trimFlag));
final StringBuilder buffer = new StringBuilder();
final NodeList list = element.getChildNodes();
boolean hasChildren = false;
for (int i = 0; i < list.getLength(); i++) {
final Node w3cNode = list.item(i);
if (w3cNode instanceof Element) {
final Element child = (Element) w3cNode;
final ImmutableNode.Builder childNode = new ImmutableNode.Builder();
childNode.name(child.getTagName());
final MutableObject<String> refChildValue = new MutableObject<>();
final Map<String, String> attrmap = constructHierarchy(childNode, refChildValue, child, elemRefs, trimFlag, level + 1);
final boolean childTrim = Boolean.parseBoolean(attrmap.remove(ATTR_SPACE_INTERNAL));
childNode.addAttributes(attrmap);
final ImmutableNode newChild = createChildNodeWithValue(node, childNode, child, refChildValue.get(), childTrim, attrmap, elemRefs);
if (elemRefs != null && !elemRefs.containsKey(newChild)) {
elemRefs.put(newChild, child);
}
hasChildren = true;
} else if (w3cNode instanceof Text) {
final Text data = (Text) w3cNode;
buffer.append(data.getData());
}
}
boolean childrenFlag = false;
if (hasChildren || trimFlag) {
childrenFlag = hasChildren || attributes.size() > 1;
}
final String text = determineValue(buffer.toString(), childrenFlag, trimFlag);
if (!text.isEmpty() || !childrenFlag && level != 0) {
refValue.setValue(text);
}
return attributes;
}
/**
* Creates a new child node, assigns its value, and adds it to its parent. This method also deals with elements whose value is a list. In this case multiple
* child elements must be added. The return value is the first child node which was added.
*
* @param parent the builder for the parent element.
* @param child the builder for the child element.
* @param elem the associated XML element.
* @param value the value of the child element.
* @param trim flag whether texts of elements should be trimmed.
* @param attrmap a map with the attributes of the current node.
* @param elemRefs a map for assigning references objects to nodes; can be <strong>null</strong>, then reference objects are irrelevant.
* @return the first child node added to the parent.
*/
private ImmutableNode createChildNodeWithValue(final ImmutableNode.Builder parent, final ImmutableNode.Builder child, final Element elem,
final String value, final boolean trim, final Map<String, String> attrmap, final Map<ImmutableNode, Object> elemRefs) {
final ImmutableNode addedChildNode;
final Collection<String> values;
if (value != null) {
values = getListDelimiterHandler().split(value, trim);
} else {
values = Collections.emptyList();
}
if (values.size() > 1) {
final Map<ImmutableNode, Object> refs = isSingleElementList(elem) ? elemRefs : null;
final Iterator<String> it = values.iterator();
// Create new node for the original child's first value
child.value(it.next());
addedChildNode = child.create();
parent.addChild(addedChildNode);
XMLListReference.assignListReference(refs, addedChildNode, elem);
// add multiple new children
while (it.hasNext()) {
final ImmutableNode.Builder c = new ImmutableNode.Builder();
c.name(addedChildNode.getNodeName());
c.value(it.next());
c.addAttributes(attrmap);
final ImmutableNode newChild = c.create();
parent.addChild(newChild);
XMLListReference.assignListReference(refs, newChild, null);
}
} else {
if (values.size() == 1) {
// we will have to replace the value because it might
// contain escaped delimiters
child.value(values.iterator().next());
}
addedChildNode = child.create();
parent.addChild(addedChildNode);
}
return addedChildNode;
}
/**
* Creates a DOM document from the internal tree of configuration nodes.
*
* @return the new document.
* @throws ConfigurationException if an error occurs.
*/
private Document createDocument() throws ConfigurationException {
final ReferenceNodeHandler handler = getReferenceHandler();
final XMLDocumentHelper docHelper = (XMLDocumentHelper) handler.getReference(handler.getRootNode());
final XMLDocumentHelper newHelper = docHelper == null ? XMLDocumentHelper.forNewDocument(getRootElementName()) : docHelper.createCopy();
final XMLBuilderVisitor builder = new XMLBuilderVisitor(newHelper, getListDelimiterHandler());
builder.handleRemovedNodes(handler);
builder.processDocument(handler);
initRootElementText(newHelper.getDocument(), getModel().getNodeHandler().getRootNode().getValue());
return newHelper.getDocument();
}
/**
* Creates the {@code DocumentBuilder} to be used for loading files. This implementation checks whether a specific
* {@code DocumentBuilder} has been set. If this is the case, this one is used. Otherwise a default builder is created.
* Depending on the value of the validating flag this builder will be a validating or a non validating
* {@code DocumentBuilder}.
*
* @return the {@code DocumentBuilder} for loading configuration files.
* @throws ParserConfigurationException if an error occurs.
* @since 1.2
*/
protected DocumentBuilder createDocumentBuilder() throws ParserConfigurationException {
if (getDocumentBuilder() != null) {
return getDocumentBuilder();
}
final DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
if (isValidating()) {
factory.setValidating(true);
if (isSchemaValidation()) {
factory.setNamespaceAware(true);
factory.setAttribute(JAXP_SCHEMA_LANGUAGE, W3C_XML_SCHEMA);
}
}
final DocumentBuilder result = factory.newDocumentBuilder();
result.setEntityResolver(this.entityResolver);
if (isValidating()) {
// register an error handler which detects validation errors
result.setErrorHandler(new DefaultHandler() {
@Override
public void error(final SAXParseException ex) throws SAXException {
throw ex;
}
});
}
return result;
}
/**
* Creates and initializes the transformer used for save operations. This base implementation initializes all of the
* default settings like indentation mode and the DOCTYPE. Derived classes may overload this method if they have
* specific needs.
*
* @return the transformer to use for a save operation.
* @throws ConfigurationException if an error occurs.
* @since 1.3
*/
protected Transformer createTransformer() throws ConfigurationException {
final Transformer transformer = XMLDocumentHelper.createTransformer();
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
transformer.setOutputProperty(INDENT_AMOUNT_PROPERTY, Integer.toString(DEFAULT_INDENT_SIZE));
if (locator != null && locator.getEncoding() != null) {
transformer.setOutputProperty(OutputKeys.ENCODING, locator.getEncoding());
}
if (publicID != null) {
transformer.setOutputProperty(OutputKeys.DOCTYPE_PUBLIC, publicID);
}
if (systemID != null) {
transformer.setOutputProperty(OutputKeys.DOCTYPE_SYSTEM, systemID);
}
return transformer;
}
/**
* Gets the XML document this configuration was loaded from. The return value is <strong>null</strong> if this configuration
* was not loaded from a XML document.
*
* @return the XML document this configuration was loaded from.
*/
public Document getDocument() {
final XMLDocumentHelper docHelper = getDocumentHelper();
return docHelper != null ? docHelper.getDocument() : null;
}
/**
* Gets the {@code DocumentBuilder} object that is used for loading documents. If no specific builder has been set,
* this method returns <strong>null</strong>.
*
* @return the {@code DocumentBuilder} for loading new documents.
* @since 1.2
*/
public DocumentBuilder getDocumentBuilder() {
return documentBuilder;
}
/**
* Gets the helper object for managing the underlying document.
*
* @return the {@code XMLDocumentHelper}.
*/
private XMLDocumentHelper getDocumentHelper() {
final ReferenceNodeHandler handler = getReferenceHandler();
return (XMLDocumentHelper) handler.getReference(handler.getRootNode());
}
/**
* Gets the EntityResolver.
*
* @return The EntityResolver.
* @since 1.7
*/
public EntityResolver getEntityResolver() {
return this.entityResolver;
}
/**
* Gets the public ID of the DOCTYPE declaration from the loaded XML document. This is <strong>null</strong> if no document has
* been loaded yet or if the document does not contain a DOCTYPE declaration with a public ID.
*
* @return the public ID.
* @since 1.3
*/
public String getPublicID() {
return syncReadValue(publicID, false);
}
/**
* Gets the extended node handler with support for references.
*
* @return the {@code ReferenceNodeHandler}.
*/
private ReferenceNodeHandler getReferenceHandler() {
return getSubConfigurationParentModel().getReferenceNodeHandler();
}
/**
* Gets the name of the root element. If this configuration was loaded from a XML document, the name of this
* document's root element is returned. Otherwise it is possible to set a name for the root element that will be used
* when this configuration is stored.
*
* @return the name of the root element.
*/
@Override
protected String getRootElementNameInternal() {
final Document doc = getDocument();
if (doc == null) {
return rootElementName == null ? DEFAULT_ROOT_NAME : rootElementName;
}
return doc.getDocumentElement().getNodeName();
}
/**
* Gets the system ID of the DOCTYPE declaration from the loaded XML document. This is <strong>null</strong> if no document has
* been loaded yet or if the document does not contain a DOCTYPE declaration with a system ID.
*
* @return the system ID.
* @since 1.3
*/
public String getSystemID() {
return syncReadValue(systemID, false);
}
/**
* {@inheritDoc} Stores the passed in locator for the upcoming IO operation.
*/
@Override
public void initFileLocator(final FileLocator loc) {
locator = loc;
}
/**
* Initializes this configuration from an XML document.
*
* @param docHelper the helper object with the document to be parsed.
* @param elemRefs a flag whether references to the XML elements should be set.
*/
private void initProperties(final XMLDocumentHelper docHelper, final boolean elemRefs) {
setPublicID(docHelper.getSourcePublicID());
setSystemID(docHelper.getSourceSystemID());
initProperties(docHelper, elemRefs, docHelper.getDocument().getDocumentElement());
}
private void initProperties(final XMLDocumentHelper docHelper, final boolean elemRefs, final Element element) {
final ImmutableNode.Builder rootBuilder = new ImmutableNode.Builder();
final MutableObject<String> rootValue = new MutableObject<>();
final Map<ImmutableNode, Object> elemRefMap = elemRefs ? new HashMap<>() : null;
final Map<String, String> attributes = constructHierarchy(rootBuilder, rootValue, element, elemRefMap, true, 0);
attributes.remove(ATTR_SPACE_INTERNAL);
final ImmutableNode top = rootBuilder.value(rootValue.get()).addAttributes(attributes).create();
getSubConfigurationParentModel().mergeRoot(top, element.getTagName(), elemRefMap, elemRefs ? docHelper : null, this);
}
/**
* Sets the text of the root element of a newly created XML Document.
*
* @param doc the document.
* @param value the new text to be set.
*/
private void initRootElementText(final Document doc, final Object value) {
final Element elem = doc.getDocumentElement();
final NodeList children = elem.getChildNodes();
// Remove all existing text nodes
for (int i = 0; i < children.getLength(); i++) {
final Node nd = children.item(i);
if (nd.getNodeType() == Node.TEXT_NODE) {
elem.removeChild(nd);
}
}
if (value != null) {
// Add a new text node
elem.appendChild(doc.createTextNode(String.valueOf(value)));
}
}
/**
* Returns the value of the schemaValidation flag.
*
* @return the schemaValidation flag.
* @since 1.7
*/
public boolean isSchemaValidation() {
return schemaValidation;
}
/**
* Returns the value of the validating flag.
*
* @return the validating flag.
* @since 1.2
*/
public boolean isValidating() {
return validating;
}
/**
* Loads a configuration file from the specified input source.
*
* @param source the input source.
* @throws ConfigurationException if an error occurs.
*/
private void load(final InputSource source) throws ConfigurationException {
if (locator == null) {
throw new ConfigurationException(
"Load operation not properly initialized! Do not call read(InputStream) directly, but use a FileHandler to load a configuration.");
}
try {
final URL sourceURL = locator.getSourceURL();
if (sourceURL != null) {
source.setSystemId(sourceURL.toString());
}
final DocumentBuilder builder = createDocumentBuilder();
final Document newDocument = builder.parse(source);
final Document oldDocument = getDocument();
initProperties(XMLDocumentHelper.forSourceDocument(newDocument), oldDocument == null);
} catch (final SAXParseException spe) {
throw new ConfigurationException(spe, "Error parsing system ID %s", source.getSystemId());
} catch (final Exception e) {
getLogger().debug("Unable to load the configuration: " + e);
throw new ConfigurationException("Unable to load the configuration", e);
}
}
/**
* Loads the configuration from the given XML DOM Element.
* <p>
* This method can be used to initialize the configuration from an XML element in a document that has already been parsed. This is especially useful if the
* configuration is only a part of a larger XML document.
* </p>
*
* @param element the input element.
* @throws ConfigurationException if an error occurs.
* @since 2.14.0
*/
public void read(final Element element) throws ConfigurationException {
try {
initProperties(getDocumentHelper(), getDocument() == null, element);
} catch (final Exception e) {
getLogger().debug("Unable to load the configuration: " + e);
throw new ConfigurationException(e, "Unable to load the configuration %s", element);
}
}
/**
* Loads the configuration from the given input stream. This is analogous to {@link #read(Reader)}, but data is read
* from a stream. Note that this method will be called most time when reading an XML configuration source. By reading
* XML documents directly from an input stream, the file's encoding can be correctly dealt with.
*
* @param in the input stream.
* @throws ConfigurationException if an error occurs.
* @throws IOException if an IO error occurs.
*/
@Override
public void read(final InputStream in) throws ConfigurationException, IOException {
load(new InputSource(in));
}
/**
* Loads the configuration from the given reader. Note that the {@code clear()} method is not called, so the properties
* contained in the loaded file will be added to the current set of properties.
*
* @param in the reader.
* @throws ConfigurationException if an error occurs.
* @throws IOException if an IO error occurs.
*/
@Override
public void read(final Reader in) throws ConfigurationException, IOException {
load(new InputSource(in));
}
/**
* Sets the {@code DocumentBuilder} object to be used for loading documents. This method makes it possible to specify
* the exact document builder. So an application can create a builder, configure it for its special needs, and then pass
* it to this method.
*
* @param documentBuilder the document builder to be used; if undefined, a default builder will be used.
* @since 1.2
*/
public void setDocumentBuilder(final DocumentBuilder documentBuilder) {
this.documentBuilder = documentBuilder;
}
/**
* Sets a new EntityResolver. Setting this will cause RegisterEntityId to have no effect.
*
* @param resolver The EntityResolver to use.
* @since 1.7
*/
public void setEntityResolver(final EntityResolver resolver) {
this.entityResolver = resolver;
}
/**
* Sets the public ID of the DOCTYPE declaration. When this configuration is saved, a DOCTYPE declaration will be
* constructed that contains this public ID.
*
* @param publicID the public ID.
* @since 1.3
*/
public void setPublicID(final String publicID) {
syncWrite(() -> this.publicID = publicID, false);
}
/**
* Sets the name of the root element. This name is used when this configuration object is stored in an XML file. Note
* that setting the name of the root element works only if this configuration has been newly created. If the
* configuration was loaded from an XML file, the name cannot be changed and an {@code UnsupportedOperationException}
* exception is thrown. Whether this configuration has been loaded from an XML document or not can be found out using
* the {@code getDocument()} method.
*
* @param name the name of the root element.
*/
public void setRootElementName(final String name) {
beginRead(true);
try {
if (getDocument() != null) {
throw new UnsupportedOperationException("The name of the root element cannot be changed when loaded from an XML document!");
}
rootElementName = name;
} finally {
endRead();
}
}
/**
* Sets the value of the schemaValidation flag. This flag determines whether DTD or Schema validation should be used.
* This flag is evaluated only if no custom {@code DocumentBuilder} was set. If set to true the XML document must
* contain a schemaLocation definition that provides resolvable hints to the required schemas.
*
* @param schemaValidation the validating flag.
* @since 1.7
*/
public void setSchemaValidation(final boolean schemaValidation) {
this.schemaValidation = schemaValidation;
if (schemaValidation) {
this.validating = true;
}
}
/**
* Sets the system ID of the DOCTYPE declaration. When this configuration is saved, a DOCTYPE declaration will be
* constructed that contains this system ID.
*
* @param systemID the system ID.
* @since 1.3
*/
public void setSystemID(final String systemID) {
syncWrite(() -> this.systemID = systemID, false);
}
/**
* Sets the value of the validating flag. This flag determines whether DTD/Schema validation should be performed when
* loading XML documents. This flag is evaluated only if no custom {@code DocumentBuilder} was set.
*
* @param validating the validating flag.
* @since 1.2
*/
public void setValidating(final boolean validating) {
if (!schemaValidation) {
this.validating = validating;
}
}
/**
* Validate the document against the Schema.
*
* @throws ConfigurationException if the validation fails.
*/
public void validate() throws ConfigurationException {
syncWrite(() -> {
try {
final StringWriter writer = new StringWriter();
final Result result = new StreamResult(writer);
XMLDocumentHelper.transform(createTransformer(), new DOMSource(createDocument()), result);
final Reader reader = new StringReader(writer.getBuffer().toString());
createDocumentBuilder().parse(new InputSource(reader));
} catch (final SAXException | IOException | ParserConfigurationException pce) {
throw new ConfigurationException("Validation failed", pce);
}
}, false);
}
/**
* Saves the configuration to the specified writer.
*
* @param writer the writer used to save the configuration.
* @throws ConfigurationException if an error occurs.
* @throws IOException if an IO error occurs.
*/
@Override
public void write(final Writer writer) throws ConfigurationException, IOException {
write(writer, createTransformer());
}
/**
* Saves the configuration to the specified writer.
*
* @param writer the writer used to save the configuration.
* @param transformer How to transform this configuration.
* @throws ConfigurationException if an error occurs.
* @since 2.7.0
*/
public void write(final Writer writer, final Transformer transformer) throws ConfigurationException {
final Source source = new DOMSource(createDocument());
final Result result = new StreamResult(writer);
XMLDocumentHelper.transform(transformer, source, result);
}
}