/*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* Memory.java
* Copyright (C) 2005-2012 University of Waikato, Hamilton, New Zealand
*
*/
package weka.core;
import java.lang.management.ManagementFactory;
import java.lang.management.MemoryMXBean;
import java.lang.management.MemoryUsage;
import javax.swing.JCheckBox;
import javax.swing.JOptionPane;
/**
* A little helper class for Memory management. The memory management can be
* disabled by using the setEnabled(boolean) method.
*
* @author FracPete (fracpete at waikato dot ac dot nz)
* @version $Revision: 9493 $
* @see #setEnabled(boolean)
*/
public class Memory implements RevisionHandler {
/** whether memory management is enabled */
protected static boolean m_Enabled = true;
/** whether a GUI is present */
protected boolean m_UseGUI = false;
/** the managed bean to use */
protected static MemoryMXBean m_MemoryMXBean = ManagementFactory
.getMemoryMXBean();
/** the last MemoryUsage object obtained */
protected MemoryUsage m_MemoryUsage = null;
/**
* initializes the memory management without GUI support
*/
public Memory() {
this(false);
}
/**
* initializes the memory management
*
* @param useGUI whether a GUI is present
*/
public Memory(boolean useGUI) {
m_UseGUI = useGUI;
}
/**
* returns whether the memory management is enabled
*
* @return true if enabled
*/
public boolean isEnabled() {
return m_Enabled;
}
/**
* sets whether the memory management is enabled
*
* @param value true if the management should be enabled
*/
public void setEnabled(boolean value) {
m_Enabled = value;
}
/**
* whether to display a dialog in case of a problem (= TRUE) or just print on
* stderr (= FALSE)
*
* @return true if the GUI is used
*/
public boolean getUseGUI() {
return m_UseGUI;
}
/**
* returns the initial size of the JVM heap, obtains a fresh MemoryUsage
* object to do so.
*
* @return the initial size in bytes
*/
public long getInitial() {
m_MemoryUsage = m_MemoryMXBean.getHeapMemoryUsage();
return m_MemoryUsage.getInit();
}
/**
* returns the currently used size of the JVM heap, obtains a fresh
* MemoryUsage object to do so.
*
* @return the used size in bytes
*/
public long getCurrent() {
m_MemoryUsage = m_MemoryMXBean.getHeapMemoryUsage();
return m_MemoryUsage.getUsed();
}
/**
* returns the maximum size of the JVM heap, obtains a fresh MemoryUsage
* object to do so.
*
* @return the maximum size in bytes
*/
public long getMax() {
m_MemoryUsage = m_MemoryMXBean.getHeapMemoryUsage();
return m_MemoryUsage.getMax();
}
/**
* checks if there's still enough memory left by checking whether there is
* still a 50MB margin between getUsed() and getMax(). if ENABLED is true,
* then false is returned always. updates the MemoryUsage variable before
* checking.
*
* @return true if out of memory (only if management enabled, otherwise always
* false)
*/
public boolean isOutOfMemory() {
m_MemoryUsage = m_MemoryMXBean.getHeapMemoryUsage();
if (isEnabled()) {
return ((m_MemoryUsage.getMax() - m_MemoryUsage.getUsed()) < 52428800);
} else
return false;
}
/**
* Checks to see if memory is running low. Low is defined as available memory
* less than 20% of max memory.
*
* @return true if memory is running low
*/
public boolean memoryIsLow() {
m_MemoryUsage = m_MemoryMXBean.getHeapMemoryUsage();
if (isEnabled()) {
long lowThreshold = (long) (0.2 * m_MemoryUsage.getMax());
// min threshold of 100Mb
if (lowThreshold < 104857600) {
lowThreshold = 104857600;
}
long avail = m_MemoryUsage.getMax() - m_MemoryUsage.getUsed();
return (avail < lowThreshold);
} else {
return false;
}
}
/**
* returns the amount of bytes as MB
*
* @return the MB amount
*/
public static double toMegaByte(long bytes) {
return (bytes / (double) (1024 * 1024));
}
/**
* prints an error message if OutOfMemory (and if GUI is present a dialog),
* otherwise nothing happens. isOutOfMemory() has to be called beforehand,
* since it sets all the memory parameters.
*
* @see #isOutOfMemory()
* @see #m_Enabled
*/
public void showOutOfMemory() {
if (!isEnabled() || (m_MemoryUsage == null))
return;
System.gc();
String msg = "Not enough memory (less than 50MB left on heap). Please load a smaller "
+ "dataset or use a larger heap size.\n"
+ "- initial heap size: "
+ Utils.doubleToString(toMegaByte(m_MemoryUsage.getInit()), 1)
+ "MB\n"
+ "- current memory (heap) used: "
+ Utils.doubleToString(toMegaByte(m_MemoryUsage.getUsed()), 1)
+ "MB\n"
+ "- max. memory (heap) available: "
+ Utils.doubleToString(toMegaByte(m_MemoryUsage.getMax()), 1)
+ "MB\n"
+ "\n"
+ "Note:\n"
+ "The Java heap size can be specified with the -Xmx option.\n"
+ "E.g., to use 128MB as heap size, the command line looks like this:\n"
+ " java -Xmx128m -classpath ...\n"
+ "This does NOT work in the SimpleCLI, the above java command refers\n"
+ "to the one with which Weka is started. See the Weka FAQ on the web\n"
+ "for further info.";
System.err.println(msg);
if (getUseGUI())
JOptionPane.showMessageDialog(null, msg, "OutOfMemory",
JOptionPane.WARNING_MESSAGE);
}
/**
* Prints a warning message if memoryIsLow (and if GUI is present a dialog).
*
* @return true if user opts to continue, disabled or GUI is not present.
*/
public boolean showMemoryIsLow() {
if (!isEnabled() || (m_MemoryUsage == null))
return true;
String msg = "Warning: memory is running low - available heap space is less than "
+ "20% of maximum or 100MB (whichever is greater)\n\n"
+ "- initial heap size: "
+ Utils.doubleToString(toMegaByte(m_MemoryUsage.getInit()), 1)
+ "MB\n"
+ "- current memory (heap) used: "
+ Utils.doubleToString(toMegaByte(m_MemoryUsage.getUsed()), 1)
+ "MB\n"
+ "- max. memory (heap) available: "
+ Utils.doubleToString(toMegaByte(m_MemoryUsage.getMax()), 1)
+ "MB\n\n"
+ "Consider deleting some results before continuing.\nCheck the Weka FAQ "
+ "on the web for suggestions on how to save memory.\n"
+ "Note that Weka will shut down when less than 50MB remain."
+ "\nDo you wish to continue regardless?\n\n";
System.err.println(msg);
/* if (getUseGUI()) {
if (!Utils.getDontShowDialog("weka.core.Memory.LowMemoryWarning")) {
JCheckBox dontShow = new JCheckBox("Do not show this message again");
Object[] stuff = new Object[2];
stuff[0] = msg;
stuff[1] = dontShow;
int result = JOptionPane.showConfirmDialog(null, stuff, "Memory",
JOptionPane.YES_NO_OPTION);
if (dontShow.isSelected()) {
try {
Utils.setDontShowDialog("weka.core.Memory.LowMemoryWarning");
} catch (Exception ex) {
// quietly ignore
}
}
return (result == JOptionPane.YES_OPTION);
}
}
*/
return true;
}
/**
* stops all the current threads, to make a restart possible
*/
public void stopThreads() {
int i;
Thread[] thGroup;
Thread t;
thGroup = new Thread[Thread.activeCount()];
Thread.enumerate(thGroup);
for (i = 0; i < thGroup.length; i++) {
t = thGroup[i];
if (t != null) {
if (t != Thread.currentThread()) {
if (t.getName().startsWith("Thread"))
t.stop();
else if (t.getName().startsWith("AWT-EventQueue"))
t.stop();
}
}
}
thGroup = null;
System.gc();
}
/**
* Returns the revision string.
*
* @return the revision
*/
@Override
public String getRevision() {
return RevisionUtils.extract("$Revision: 9493 $");
}
/**
* prints only some statistics
*
* @param args the commandline arguments - ignored
*/
public static void main(String[] args) {
Memory mem = new Memory();
System.out.println("Initial memory: "
+ Utils.doubleToString(Memory.toMegaByte(mem.getInitial()), 1) + "MB"
+ " (" + mem.getInitial() + ")");
System.out.println("Max memory: "
+ Utils.doubleToString(Memory.toMegaByte(mem.getMax()), 1) + "MB"
+ " (" + mem.getMax() + ")");
}
}