[Jrobin-commits] src/jrobin/core FetchData.java,NONE,1.1

[<sa...@us...>]

Update of /cvsroot/jrobin/src/jrobin/core
In directory sc8-pr-cvs1:/tmp/cvs-serv27580/jrobin/core

Added Files:
	FetchData.java 
Log Message:
FetchData class, use it to replace previous fetching mechanism...

--- NEW FILE: FetchData.java ---
/* ============================================================
 * JRobin : Pure java implementation of RRDTool's functionality
 * ============================================================
 *
 * Project Info:  http://www.sourceforge.net/projects/jrobin
 * Project Lead:  Sasa Markovic (sa...@eu...);
 *
 * (C) Copyright 2003, by Sasa Markovic.
 *
 * This library is free software; you can redistribute it and/or modify it under the terms
 * of the GNU Lesser General Public License as published by the Free Software Foundation;
 * either version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with this
 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 */

package jrobin.core;

import java.io.IOException;

/**
 * Class used to represent data fetched from the RRD file.
 * Object of this class is created when the method
 * {@link jrobin.core.FetchRequest#fetchData() fetchData()} is
 * called on a {@link jrobin.core.FetchRequest FetchRequest} object.<p>
 *
 * Data returned from the RRD file is, simply, just one big table filled with
 * timestamps and corresponding datasource values.
 * Use {@link #getRowCount() getRowCount()} method to count the number
 * of returned timestamps (table rows).<p>
 *
 * The first table column is filled with timestamps. Time intervals
 * between consecutive timestamps are guaranteed to be equal. Use
 * {@link #getTimestamps() getTimestamps()} method to get an array of
 * timestamps returned.<p>
 *
 * Remaining columns are filled with datasource values for the whole timestamp range,
 * on a column-per-datasource basis. Use {@link #getColumnCount() getColumnCount()} to find
 * the number of datasources and {@link #getValues(int) getValues(i)} method to obtain
 * all values for the i-th datasource. Returned datasource values correspond to
 * the values returned with {@link #getTimestamps() getTimestamps()} method.<p>
 */
public class FetchData {
	private FetchRequest request;
	private Archive matchingArchive;
	private String[] dsNames;
	private long[] timestamps;
	private double[][] values;

	FetchData(Archive matchingArchive, FetchRequest request) throws IOException {
		this.matchingArchive = matchingArchive;
		this.dsNames = matchingArchive.getParentDb().getDsNames();
		this.request = request;
	}

	void setTimestamps(long[] timestamps) {
		this.timestamps = timestamps;
	}

	void setValues(double[][] values) {
		this.values = values;
	}

	/**
	 * Returns the number of rows fetched from the underlying RRD file.
	 * Each row represents datasource values for the specific timestamp.
	 * @return Number of rows.
	 */
    public int getRowCount() {
		return timestamps.length;
	}

    /**
	 * Returns the number of columns fetched from the underlying RRD file.
	 * This number is always equal to the number of datasources defined
	 * in the RRD file. Each column represents values of a single datasource.
	 * @return Number of columns (datasources).
	 */
	public int getColumnCount() {
		return dsNames.length;
	}

	/**
	 * Returns the number of rows fetched from the underlying RRD file.
	 * Each row represents datasource values for the specific timestamp.
	 * @param rowIndex Row index.
	 * @return FetchPoint object which represents datasource values for the
	 * specific timestamp.
	 */
	public FetchPoint getRow(int rowIndex) {
		int numCols = getColumnCount();
		FetchPoint point = new FetchPoint(timestamps[rowIndex], getColumnCount());
		for(int dsIndex = 0; dsIndex < numCols; dsIndex++) {
			point.setValue(dsIndex, values[dsIndex][rowIndex]);
		}
		return point;
	}

	/**
	 * Returns an array of timestamps covering the whole range specified in the
	 * {@link FetchRequest FetchReguest} object.
	 * @return Array of equidistant timestamps.
	 */
	public long[] getTimestamps() {
		return timestamps;
	}

	/**
	 * Returns all archived values for a single datasource.
	 * Returned values correspond to timestamps
	 * returned with {@link #getTimestamps() getTimestamps()} method.
	 * @param dsIndex Datasource index.
	 * @return Array of single datasource values.
	 */
	public double[] getValues(int dsIndex) {
		return values[dsIndex];
	}

	/**
	 * Returns all archived values for a single datasource.
	 * Returned values correspond to timestamps
	 * returned with {@link #getTimestamps() getTimestamps()} method.
	 * @param dsName Datasource name.
	 * @return Array of single datasource values.
	 * @throws RrdException Thrown if no matching datasource name is found.
	 */
	public double[] getValues(String dsName) throws RrdException {
		for(int dsIndex = 0; dsIndex < getColumnCount(); dsIndex++) {
			if(dsName.equals(dsNames[dsIndex])) {
				return getValues(dsIndex);
			}
		}
		throw new RrdException("Datasource [" + dsName + "] not found");
	}

	/**
	 * Returns {@link FetchRequest FetchRequest} object used to create this FetchData object.
	 * @return Fetch request object.
	 */
	public FetchRequest getRequest() {
		return request;
	}

    /**
	 * Returns the first timestamp in this FetchData object.
	 * @return The smallest timestamp.
	 */
	public long getFirstTimestamp() {
		return timestamps[0];
	}

	/**
	 * Returns the last timestamp in this FecthData object.
	 * @return The biggest timestamp.
	 */
	public long getLastTimestamp() {
		return timestamps[timestamps.length - 1];
	}

	/**
	 * Returns Archive object which is determined to be the best match for the
	 * timestamps specified in the fetch request. All datasource values are obtained
	 * from round robin archives belonging to this archive.
	 * @return Matching archive.
	 */
	public Archive getMatchingArchive() {
		return matchingArchive;
	}

	/**
	 * Returns array of datasource names found in the underlying RRD file.
	 * @return Array of datasource names.
	 */
	public String[] getDsNames() {
		return dsNames;
	}

	/**
	 * Dumps the content of the whole FetchData object to stdout. Useful for debugging.
	 */
	public void dump() {
		for(int i = 0; i < getRowCount(); i++) {
			System.out.println(getRow(i).dump());
		}
	}

}