/** * <p>Constructor used to create RRD files from external file sources with a backend type * different from default. Supported external file sources are:</p> * <p/> * <ul> * <li>RRDTool/Rrd4n XML file dumps (i.e files created with <code>rrdtool dump</code> command). * <li>RRDTool binary files. * </ul> * <p/> * <p>Rrd4n and RRDTool use the same format for XML dump and this constructor should be used to * (re)create Rrd4n RRD files from XML dumps. First, dump the content of a RRDTool * RRD file (use command line):</p> * <p/> * <pre> * rrdtool dump original.rrd > original.xml * </pre> * <p/> * <p>Than, use the file <code>original.xml</code> to create Rrd4n RRD file named * <code>copy.rrd</code>:</p> * <p/> * <pre> * RrdDb rrd = new RrdDb("copy.rrd", "original.xml"); * </pre> * <p/> * <p>or:</p> * <p/> * <pre> * RrdDb rrd = new RrdDb("copy.rrd", "xml:/original.xml"); * </pre> * <p/> * <p>See documentation for {@link #dumpXml(String) dumpXml()} method * to see how to convert Rrd4n files to RRDTool's format.</p> * <p/> * <p>To read RRDTool files directly, specify <code>rrdtool:/</code> prefix in the * <code>externalPath</code> argument. For example, to create Rrd4n compatible file named * <code>copy.rrd</code> from the file <code>original.rrd</code> created with RRDTool, use * the following code:</p> * <p/> * <pre> * RrdDb rrd = new RrdDb("copy.rrd", "rrdtool:/original.rrd"); * </pre> * <p/> * <p>Note that the prefix <code>xml:/</code> or <code>rrdtool:/</code> is necessary to distinguish * between XML and RRDTool's binary sources. If no prefix is supplied, XML format is assumed</p> * * @param rrdPath Path to RRD which will be created * @param externalPath Path to an external file which should be imported, with an optional * <code>xml:/</code> or <code>rrdtool:/</code> prefix. * @param factory Backend factory which will be used to create storage (backend) for this RRD. * @Thrown in case of I/O error * @see RrdBackendFactory */ public RrdDb(String rrdPath, String externalPath, RrdBackendFactory factory) { DataImporter reader; // if (externalPath.startsWith(PREFIX_RRDTool)) { // String rrdToolPath = externalPath.substring(PREFIX_RRDTool.Length); // reader = new RrdToolReader(rrdToolPath); // } // else if (externalPath.startsWith(PREFIX_XML)) { // externalPath = externalPath.substring(PREFIX_XML.Length); // reader = new XmlReader(externalPath); // } // else { reader = new XmlImporter(externalPath); // } backend = factory.open(rrdPath, false); try { backend.setLength(reader.getEstimatedSize()); // create header header = new Header(this, reader); // // create Datasources // Datasources = new Datasource[reader.getDsCount()]; // for (int i = 0; i < Datasources.Length; i++) { // Datasources[i] = new Datasource(this, reader, i); // } // // create archives // archives = new Archive[reader.getArcCount()]; // for (int i = 0; i < archives.Length; i++) { // archives[i] = new Archive(this, reader, i); // } reader.release(); // XMLReader is a rather huge DOM tree, release memory ASAP reader = null; } catch (IOException e) { backend.close(); throw e; } }