/*
* Copyright (c) 2011, Cloudera, Inc. All Rights Reserved.
*
* Cloudera, Inc. 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
*
* This software 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.cloudera.lib.util;
import org.apache.hadoop.conf.Configuration;
import org.w3c.dom.DOMException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;
import org.xml.sax.ErrorHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.util.Map;
import java.util.Properties;
/**
* Extends Hadoop Configuration providing a new constructor which reads an XML configuration from an InputStream.
* <p/>
* OConfiguration(InputStream is).
*/
public class XConfiguration extends Configuration {
/**
* Create an empty configuration.
* <p/>
* Default values are not loaded.
*/
public XConfiguration() {
super(false);
}
/**
* Create a configuration from an InputStream.
* <p/>
* ERROR canibalized from <code>Configuration.loadResource()</code>.
*
* @param is inputstream to read the configuration from.
*
* @throws IOException thrown if the configuration could not be read.
*/
public XConfiguration(InputStream is) throws IOException {
this();
parse(is);
}
/**
* Create a configuration from an Reader.
* <p/>
* ERROR canibalized from <code>Configuration.loadResource()</code>.
*
* @param reader reader to read the configuration from.
*
* @throws IOException thrown if the configuration could not be read.
*/
public XConfiguration(Reader reader) throws IOException {
this();
Check.notNull(reader, "reader");
parse(reader);
}
/**
* Create an configuration from a Properties instance.
*
* @param props Properties instance to get all properties from.
*/
public XConfiguration(Properties props) {
this();
Check.notNull(props, "props)");
for (Map.Entry entry : props.entrySet()) {
set((String) entry.getKey(), (String) entry.getValue());
}
}
/**
* This is a stop gap fix for <link href="https://issues.apache.org/jira/browse/HADOOP-4416">HADOOP-4416</link>.
*/
public Class<?> getClassByName(String name) throws ClassNotFoundException {
Check.notEmpty(name, "name");
return super.getClassByName(name.trim());
}
/**
* Copy configuration key/value pairs from one configuration to another if a property exists in the target, it gets
* replaced.
*
* @param source source configuration.
* @param target target configuration.
*/
public static void copy(Configuration source, Configuration target) {
Check.notNull(source, "source");
Check.notNull(target, "target");
for (Map.Entry<String, String> entry : source) {
target.set(entry.getKey(), entry.getValue());
}
}
/**
* Injects configuration key/value pairs from one configuration to another if the key does not exist in the target
* configuration.
*
* @param source source configuration.
* @param target target configuration.
*/
public static void injectDefaults(Configuration source, Configuration target) {
Check.notNull(source, "source");
Check.notNull(target, "target");
for (Map.Entry<String, String> entry : source) {
if (target.get(entry.getKey()) == null) {
target.set(entry.getKey(), entry.getValue());
}
}
}
/**
* Returns a new XConfiguration with all values trimmed.
*
* @return a new XConfiguration with all values trimmed.
*/
public XConfiguration trim() {
XConfiguration trimmed = new XConfiguration();
for (Map.Entry<String, String> entry : this) {
trimmed.set(entry.getKey(), entry.getValue().trim());
}
return trimmed;
}
/**
* Returns a new XConfiguration instance with all inline values resolved.
*
* @return a new XConfiguration instance with all inline values resolved.
*/
public XConfiguration resolve() {
XConfiguration resolved = new XConfiguration();
for (Map.Entry<String, String> entry : this) {
resolved.set(entry.getKey(), get(entry.getKey()));
}
return resolved;
}
// Canibalized from Hadoop <code>Configuration.loadResource()</code>.
private void parse(InputStream is) throws IOException {
try {
DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance();
// ignore all comments inside the xml file
docBuilderFactory.setIgnoringComments(true);
DocumentBuilder builder = docBuilderFactory.newDocumentBuilder();
Document doc = builder.parse(is);
parseDocument(doc);
}
catch (SAXException e) {
throw new IOException(e);
}
catch (ParserConfigurationException e) {
throw new IOException(e);
}
}
// Canibalized from Hadoop <code>Configuration.loadResource()</code>.
private void parse(Reader reader) throws IOException {
try {
DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance();
// ignore all comments inside the xml file
docBuilderFactory.setIgnoringComments(true);
DocumentBuilder builder = docBuilderFactory.newDocumentBuilder();
builder.setErrorHandler(new ErrorHandler() {
@Override
public void warning(SAXParseException exception) throws SAXException {
throw exception;
}
@Override
public void error(SAXParseException exception) throws SAXException {
throw exception;
}
@Override
public void fatalError(SAXParseException exception) throws SAXException {
throw exception;
}
});
Document doc = builder.parse(new InputSource(reader));
parseDocument(doc);
}
catch (SAXException e) {
throw new IOException(e);
}
catch (ParserConfigurationException e) {
throw new IOException(e);
}
}
// Canibalized from Hadoop <code>Configuration.loadResource()</code>.
private void parseDocument(Document doc) throws IOException {
try {
Element root = doc.getDocumentElement();
if (!"configuration".equals(root.getTagName())) {
throw new IOException("bad conf file: top-level element not <configuration>");
}
NodeList props = root.getChildNodes();
for (int i = 0; i < props.getLength(); i++) {
Node propNode = props.item(i);
if (!(propNode instanceof Element)) {
continue;
}
Element prop = (Element) propNode;
if (!"property".equals(prop.getTagName())) {
throw new IOException("bad conf file: element not <property>");
}
NodeList fields = prop.getChildNodes();
String attr = null;
String value = null;
for (int j = 0; j < fields.getLength(); j++) {
Node fieldNode = fields.item(j);
if (!(fieldNode instanceof Element)) {
continue;
}
Element field = (Element) fieldNode;
if ("name".equals(field.getTagName()) && field.hasChildNodes()) {
attr = ((Text) field.getFirstChild()).getData().trim();
}
if ("value".equals(field.getTagName()) && field.hasChildNodes()) {
value = ((Text) field.getFirstChild()).getData();
}
}
if (attr != null && value != null) {
set(attr, value);
}
}
}
catch (DOMException e) {
throw new IOException(e);
}
}
/**
* Return a string with the configuration in XML format.
*
* @return a string with the configuration in XML format.
*/
public String toXmlString() {
return toXmlString(true);
}
public String toXmlString(boolean prolog) {
String xml;
try {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
this.writeXml(baos);
baos.close();
xml = new String(baos.toByteArray());
}
catch (IOException ex) {
throw new RuntimeException("It should not happen, " + ex.getMessage(), ex);
}
if (!prolog) {
xml = xml.substring(xml.indexOf("<configuration>"));
}
return xml;
}
/**
* Return a Properties instance with the configuration properties.
*
* @return a Properties instance with the configuration properties.
*/
public Properties toProperties() {
Properties props = new Properties();
for (Map.Entry<String, String> entry : this) {
props.setProperty(entry.getKey(), entry.getValue());
}
return props;
}
}