| /** |
| * 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.hadoop.hdfs.tools.offlineEditsViewer; |
| |
| import java.io.IOException; |
| import java.io.OutputStream; |
| |
| import org.apache.hadoop.hdfs.util.XMLUtils; |
| import org.apache.hadoop.hdfs.server.namenode.FSEditLogOp; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.xml.sax.ContentHandler; |
| import org.xml.sax.SAXException; |
| import org.xml.sax.helpers.AttributesImpl; |
| |
| import org.apache.xml.serialize.OutputFormat; |
| import org.apache.xml.serialize.XMLSerializer; |
| |
| /** |
| * An XmlEditsVisitor walks over an EditLog structure and writes out |
| * an equivalent XML document that contains the EditLog's components. |
| */ |
| @InterfaceAudience.Private |
| @InterfaceStability.Unstable |
| public class XmlEditsVisitor implements OfflineEditsVisitor { |
| private final OutputStream out; |
| private ContentHandler contentHandler; |
| |
| /** |
| * Create a processor that writes to the file named and may or may not |
| * also output to the screen, as specified. |
| * |
| * @param filename Name of file to write output to |
| * @param printToScreen Mirror output to screen? |
| */ |
| public XmlEditsVisitor(OutputStream out) |
| throws IOException { |
| this.out = out; |
| OutputFormat outFormat = new OutputFormat("XML", "UTF-8", true); |
| outFormat.setIndenting(true); |
| outFormat.setIndent(2); |
| outFormat.setDoctype(null, null); |
| XMLSerializer serializer = new XMLSerializer(out, outFormat); |
| contentHandler = serializer.asContentHandler(); |
| try { |
| contentHandler.startDocument(); |
| contentHandler.startElement("", "", "EDITS", new AttributesImpl()); |
| } catch (SAXException e) { |
| throw new IOException("SAX error: " + e.getMessage()); |
| } |
| } |
| |
| /** |
| * Start visitor (initialization) |
| */ |
| @Override |
| public void start(int version) throws IOException { |
| try { |
| contentHandler.startElement("", "", "EDITS_VERSION", new AttributesImpl()); |
| StringBuilder bld = new StringBuilder(); |
| bld.append(version); |
| addString(bld.toString()); |
| contentHandler.endElement("", "", "EDITS_VERSION"); |
| } |
| catch (SAXException e) { |
| throw new IOException("SAX error: " + e.getMessage()); |
| } |
| } |
| |
| public void addString(String str) throws SAXException { |
| int slen = str.length(); |
| char arr[] = new char[slen]; |
| str.getChars(0, slen, arr, 0); |
| contentHandler.characters(arr, 0, slen); |
| } |
| |
| /** |
| * Finish visitor |
| */ |
| @Override |
| public void close(Throwable error) throws IOException { |
| try { |
| contentHandler.endElement("", "", "EDITS"); |
| if (error != null) { |
| String msg = error.getMessage(); |
| XMLUtils.addSaxString(contentHandler, "ERROR", |
| (msg == null) ? "null" : msg); |
| } |
| contentHandler.endDocument(); |
| } |
| catch (SAXException e) { |
| throw new IOException("SAX error: " + e.getMessage()); |
| } |
| out.close(); |
| } |
| |
| @Override |
| public void visitOp(FSEditLogOp op) throws IOException { |
| try { |
| op.outputToXml(contentHandler); |
| } |
| catch (SAXException e) { |
| throw new IOException("SAX error: " + e.getMessage()); |
| } |
| } |
| } |