package org.rrd4j.core;
import java.io.IOException;
import java.util.StringTokenizer;
import java.util.Arrays;
/**
* <p>Class to represent data source values for the given timestamp. Objects of this
* class are never created directly (no public constructor is provided). To learn more how
* to update RRDs, see RRDTool's
* <a href="../../../../man/rrdupdate.html" target="man">rrdupdate man page</a>.</p>
* <p>To update a RRD with Rrd4j use the following procedure:</p>
* <ol>
* <li>Obtain empty Sample object by calling method {@link org.rrd4j.core.RrdDb#createSample(long)
* createSample()} on respective {@link RrdDb RrdDb} object.
* <li>Adjust Sample timestamp if necessary (see {@link #setTime(long) setTime()} method).
* <li>Supply data source values (see {@link #setValue(String, double) setValue()}).
* <li>Call Sample's {@link #update() update()} method.
* </ol>
* <p>Newly created Sample object contains all data source values set to 'unknown'.
* You should specify only 'known' data source values. However, if you want to specify
* 'unknown' values too, use <code>Double.NaN</code>.</p>
*
* @author Sasa Markovic
*/
public class Sample {
private final RrdDb parentDb;
private long time;
private final String[] dsNames;
private final double[] values;
Sample(RrdDb parentDb, long time) throws IOException {
this.parentDb = parentDb;
this.time = time;
this.dsNames = parentDb.getDsNames();
values = new double[dsNames.length];
clearValues();
}
private void clearValues() {
Arrays.fill(values, Double.NaN);
}
/**
* Sets single data source value in the sample.
*
* @param dsName Data source name.
* @param value Data source value.
* @return This <code>Sample</code> object
* @throws java.lang.IllegalArgumentException Thrown if invalid data source name is supplied.
*/
public Sample setValue(String dsName, double value) {
for (int i = 0; i < values.length; i++) {
if (dsNames[i].equals(dsName)) {
values[i] = value;
return this;
}
}
throw new IllegalArgumentException("Datasource " + dsName + " not found");
}
/**
* Sets single datasource value using data source index. Data sources are indexed by
* the order specified during RRD creation (zero-based).
*
* @param i Data source index
* @param value Data source values
* @return This <code>Sample</code> object
* @throws java.lang.IllegalArgumentException Thrown if data source index is invalid.
*/
public Sample setValue(int i, double value) {
if (i < values.length) {
values[i] = value;
return this;
}
throw new IllegalArgumentException("Sample datasource index " + i + " out of bounds");
}
/**
* Sets some (possibly all) data source values in bulk. Data source values are
* assigned in the order of their definition inside the RRD.
*
* @param values Data source values.
* @return This <code>Sample</code> object
* @throws java.lang.IllegalArgumentException Thrown if the number of supplied values is zero or greater
* than the number of data sources defined in the RRD.
*/
public Sample setValues(double... values) {
if (values.length <= this.values.length) {
System.arraycopy(values, 0, this.values, 0, values.length);
return this;
}
throw new IllegalArgumentException("Invalid number of values specified (found " +
values.length + ", only " + dsNames.length + " allowed)");
}
/**
* Returns all current data source values in the sample.
*
* @return Data source values.
*/
public double[] getValues() {
return values;
}
/**
* Returns sample timestamp (in seconds, without milliseconds).
*
* @return Sample timestamp.
*/
public long getTime() {
return time;
}
/**
* Sets sample timestamp. Timestamp should be defined in seconds (without milliseconds).
*
* @param time New sample timestamp.
* @return This <code>Sample</code> object
*/
public Sample setTime(long time) {
this.time = time;
return this;
}
/**
* Returns an array of all data source names. If you try to set value for the data source
* name not in this array, an exception is thrown.
*
* @return Acceptable data source names.
*/
public String[] getDsNames() {
return dsNames;
}
/**
* <p>Sets sample timestamp and data source values in a fashion similar to RRDTool.
* Argument string should be composed in the following way:
* <code>timestamp:value1:value2:...:valueN</code>.</p>
* <p>You don't have to supply all datasource values. Unspecified values will be treated
* as unknowns. To specify unknown value in the argument string, use letter 'U'.</p>
*
* @param timeAndValues <p>String made by concatenating sample timestamp with corresponding
* data source values delmited with colons. For example:</p>
*
* <pre>
* 1005234132:12.2:35.6:U:24.5
* NOW:12.2:35.6:U:24.5
* </pre>
* <p>'N' stands for the current timestamp (can be replaced with 'NOW')<p>
* Method will throw an exception if timestamp is invalid (cannot be parsed as Long, and is not 'N'
* or 'NOW'). Datasource value which cannot be parsed as 'double' will be silently set to NaN.</p>
* @return This <code>Sample</code> object
* @throws java.lang.IllegalArgumentException Thrown if too many datasource values are supplied
*/
public Sample set(String timeAndValues) {
StringTokenizer tokenizer = new StringTokenizer(timeAndValues, ":", false);
int n = tokenizer.countTokens();
if (n > values.length + 1) {
throw new IllegalArgumentException("Invalid number of values specified (found " +
values.length + ", " + dsNames.length + " allowed)");
}
String timeToken = tokenizer.nextToken();
try {
time = Long.parseLong(timeToken);
}
catch (NumberFormatException nfe) {
if ("N".equalsIgnoreCase(timeToken) || "NOW".equalsIgnoreCase(timeToken)) {
time = Util.getTime();
}
else {
throw new IllegalArgumentException("Invalid sample timestamp: " + timeToken);
}
}
for (int i = 0; tokenizer.hasMoreTokens(); i++) {
try {
values[i] = Double.parseDouble(tokenizer.nextToken());
}
catch (NumberFormatException nfe) {
// NOP, value is already set to NaN
}
}
return this;
}
/**
* Stores sample in the corresponding RRD. If the update operation succeeds,
* all datasource values in the sample will be set to Double.NaN (unknown) values.
*
* @throws java.io.IOException Thrown in case of I/O error.
*/
public void update() throws IOException {
parentDb.store(this);
clearValues();
}
/**
* Creates sample with the timestamp and data source values supplied
* in the argument string and stores sample in the corresponding RRD.
* This method is just a shortcut for:
* <pre>
* set(timeAndValues);
* update();
* </pre>
*
* @param timeAndValues String made by concatenating sample timestamp with corresponding
* data source values delmited with colons. For example:<br>
* <code>1005234132:12.2:35.6:U:24.5</code><br>
* <code>NOW:12.2:35.6:U:24.5</code>
* @throws java.io.IOException Thrown in case of I/O error.
*/
public void setAndUpdate(String timeAndValues) throws IOException {
set(timeAndValues);
update();
}
/**
* Dumps sample content using the syntax of RRDTool's update command.
*
* @return Sample dump.
*/
public String dump() {
StringBuilder buffer = new StringBuilder("update \"");
buffer.append(parentDb.getRrdBackend().getPath()).append("\" ").append(time);
for (double value : values) {
buffer.append(':');
buffer.append(Util.formatDouble(value, "U", false));
}
return buffer.toString();
}
String getRrdToolCommand() {
return dump();
}
}