/*
* Copyright (c) 2008-2017, Hazelcast, Inc. All Rights Reserved.
*
* Licensed 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 com.hazelcast.config;
import com.hazelcast.logging.ILogger;
import com.hazelcast.logging.Logger;
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 javax.xml.namespace.NamespaceContext;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathFactory;
import java.io.InputStream;
import java.net.URL;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Properties;
import java.util.Set;
import static com.hazelcast.config.XmlElements.IMPORT;
import static java.lang.String.format;
/**
* Contains logic for replacing system variables in the XML file and importing XML files from different locations.
*/
public abstract class AbstractConfigBuilder extends AbstractXmlConfigHelper {
protected enum ConfigType {
SERVER("hazelcast"),
CLIENT("hazelcast-client"),
JET("hazelcast-jet");
final String name;
ConfigType(String name) {
this.name = name;
}
}
private static final ILogger LOGGER = Logger.getLogger(AbstractConfigBuilder.class);
private final Set<String> currentlyImportedFiles = new HashSet<String>();
private final XPath xpath;
public AbstractConfigBuilder() {
XPathFactory fac = XPathFactory.newInstance();
this.xpath = fac.newXPath();
xpath.setNamespaceContext(new NamespaceContext() {
@Override
public String getNamespaceURI(String prefix) {
return "hz".equals(prefix) ? xmlns : null;
}
@Override
public String getPrefix(String namespaceURI) {
return null;
}
@Override
public Iterator getPrefixes(String namespaceURI) {
return null;
}
});
}
protected void process(Node root) throws Exception {
traverseChildrenAndReplaceVariables(root);
replaceImportElementsWithActualFileContents(root);
}
private void replaceImportElementsWithActualFileContents(Node root) throws Exception {
Document document = root.getOwnerDocument();
NodeList misplacedImports = (NodeList) xpath.evaluate(
format("//hz:%s/parent::*[not(self::hz:%s)]", IMPORT.name, getXmlType().name), document, XPathConstants.NODESET);
if (misplacedImports.getLength() > 0) {
throw new InvalidConfigurationException("<import> element can appear only in the top level of the XML");
}
NodeList importTags = (NodeList) xpath.evaluate(
format("/hz:%s/hz:%s", getXmlType().name, IMPORT.name), document, XPathConstants.NODESET);
for (Node node : asElementIterable(importTags)) {
loadAndReplaceImportElement(root, node);
}
}
private void loadAndReplaceImportElement(Node root, Node node) throws Exception {
NamedNodeMap attributes = node.getAttributes();
Node resourceAttribute = attributes.getNamedItem("resource");
String resource = resourceAttribute.getTextContent();
URL url = ConfigLoader.locateConfig(resource);
if (url == null) {
throw new InvalidConfigurationException("Failed to load resource: " + resource);
}
if (!currentlyImportedFiles.add(url.getPath())) {
throw new InvalidConfigurationException("Cyclic loading of resource " + url.getPath() + " is detected!");
}
Document doc = parse(url.openStream());
Element importedRoot = doc.getDocumentElement();
traverseChildrenAndReplaceVariables(importedRoot);
replaceImportElementsWithActualFileContents(importedRoot);
for (Node fromImportedDoc : childElements(importedRoot)) {
Node importedNode = root.getOwnerDocument().importNode(fromImportedDoc, true);
root.insertBefore(importedNode, node);
}
root.removeChild(node);
}
/**
* Reads XML from InputStream and parses.
*
* @param inputStream {@link InputStream} to read from
* @return Document after parsing XML
* @throws Exception if the XML configuration cannot be parsed or is invalid
*/
protected abstract Document parse(InputStream inputStream) throws Exception;
/**
* @return system properties
*/
protected abstract Properties getProperties();
/**
* @return ConfigType of current config class as enum value.
*/
@Override
protected abstract ConfigType getXmlType();
private void traverseChildrenAndReplaceVariables(Node root) {
NamedNodeMap attributes = root.getAttributes();
if (attributes != null) {
for (int k = 0; k < attributes.getLength(); k++) {
Node attribute = attributes.item(k);
replaceVariables(attribute);
}
}
if (root.getNodeValue() != null) {
replaceVariables(root);
}
final NodeList childNodes = root.getChildNodes();
for (int k = 0; k < childNodes.getLength(); k++) {
Node child = childNodes.item(k);
traverseChildrenAndReplaceVariables(child);
}
}
private void replaceVariables(Node node) {
String value = node.getNodeValue();
StringBuilder sb = new StringBuilder(value);
int endIndex = -1;
int startIndex = sb.indexOf("${");
while (startIndex > -1) {
endIndex = sb.indexOf("}", startIndex);
if (endIndex == -1) {
LOGGER.warning("Bad variable syntax. Could not find a closing curly bracket '}' on node: " + node.getLocalName());
break;
}
String variable = sb.substring(startIndex + 2, endIndex);
String variableReplacement = getProperties().getProperty(variable);
if (variableReplacement != null) {
sb.replace(startIndex, endIndex + 1, variableReplacement);
endIndex = startIndex + variableReplacement.length();
} else {
LOGGER.warning("Could not find a value for property '" + variable + "' on node: " + node.getLocalName());
}
startIndex = sb.indexOf("${", endIndex);
}
node.setNodeValue(sb.toString());
}
}