| /* MemoryPoolMXBean.java - Interface for a memory pool bean |
| Copyright (C) 2006 Free Software Foundation |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath 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 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
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| exception statement from your version. */ |
| |
| package java.lang.management; |
| |
| /** |
| * <p> |
| * Provides access to information about one of the memory |
| * resources or pools used by the virtual machine. Instances |
| * of this bean are obtained by calling |
| * {@link ManagementFactory#getMemoryPoolMXBeans()}. One |
| * bean is returned for each memory pool provided. |
| * </p> |
| * <p> |
| * The memory pool bean allows the usage of the pool to be |
| * monitored. The bean can provide statistics on the current |
| * and peak usage of the pool, and on the threshold levels the |
| * pool uses. |
| * </p> |
| * <p> |
| * {@link getUsage()} returns an approximation of the current |
| * usage of the pool. Calls to this method are expected to be |
| * generally quick to perform; if the call is expensive, the |
| * documentation of the bean should specify so. For memory |
| * pool beans that represent the memory used by garbage |
| * collectors, the usage level includes both referenced and |
| * unreferenced objects. |
| * </p> |
| * <p> |
| * {@link getPeakUsage()} and {@link resetPeakUsage()} enable |
| * the retrieval of the peak usage level and setting it to the |
| * current usage level, respectively. Initially, the peak usage |
| * level is relative to the start of the virtual machine. |
| * </p> |
| * <p> |
| * Memory pools may also include optional support for usage thresholds. |
| * The usage threshold is a particular level of memory usage. When this |
| * value is crossed (the current memory usage becomes equal to or greater |
| * than this threshold level), the usage threshold count is increased. |
| * This feature is designed for monitoring the trend in memory usage. |
| * Support for a collection usage threshold is also provided, for |
| * particular garbage collectors. This is used to monitor the amount |
| * of memory left uncollected after a garbage collection cycle. There |
| * is no need to make special garbage collection runs to support this; |
| * the level following collection just needs to be monitored. |
| * </p> |
| * |
| * @author Andrew John Hughes (gnu_andrew@member.fsf.org) |
| * @since 1.5 |
| */ |
| public interface MemoryPoolMXBean |
| { |
| |
| /** |
| * Returns memory usage statistics after a best-effort attempt |
| * has been made to remove unused objects from the pool. This |
| * method is designed for use by the pools of garbage collectors, |
| * in order to monitor the amount of memory used after collections. |
| * It will return <code>null</code> if such functionality is |
| * unsupported by the memory pool represented by this bean. |
| * |
| * @return the memory usage of the memory pool after the most |
| * recent garbage collection cycle, or <code>null</code> |
| * if this operation is not supported. |
| */ |
| MemoryUsage getCollectionUsage(); |
| |
| /** |
| * Returns the collection usage threshold level in bytes. This |
| * value is initially zero. |
| * |
| * @return the collection usage threshold in bytes. |
| * @throws UnsupportedOperationException if the collection usage |
| * threshold is not supported. |
| * @see #getCollectionUsageThresholdCount() |
| * @see #isCollectionUsageThresholdExceeded() |
| * @see #isCollectionUsageThresholdSupported() |
| * @see #setCollectionUsageThreshold(long) |
| */ |
| long getCollectionUsageThreshold(); |
| |
| /** |
| * Returns the number of times the usage level has matched or |
| * exceeded the collection usage threshold. |
| * |
| * @return the number of times the usage level has matched |
| * or exceeded the collection usage threshold. |
| * @throws UnsupportedOperationException if the collection usage |
| * threshold is not supported. |
| * @see #getCollectionUsageThreshold() |
| * @see #isCollectionUsageThresholdExceeded() |
| * @see #isCollectionUsageThresholdSupported() |
| * @see #setCollectionUsageThreshold(long) |
| */ |
| long getCollectionUsageThresholdCount(); |
| |
| /** |
| * Returns the names of the memory managers associated with this |
| * pool. Each pool has at least one memory manager. |
| * |
| * @return an array containing the name of each memory manager |
| * responsible for this pool. |
| */ |
| String[] getMemoryManagerNames(); |
| |
| /** |
| * Returns the name of the memory pool. |
| * |
| * @return the memory pool name. |
| */ |
| String getName(); |
| |
| /** |
| * Returns memory usage statistics for the peak memory usage |
| * of the pool. The peak is the maximum memory usage occurring |
| * since the virtual machine was started or since the peak |
| * was reset by {@link #resetPeakUsage()}. The return value |
| * may be <code>null</code> if this pool is no longer valid. |
| * |
| * @return the memory usage of the memory pool at its peak, |
| * or <code>null</code> if this pool is no longer valid. |
| */ |
| MemoryUsage getPeakUsage(); |
| |
| /** |
| * Returns the type of memory used by this pool. This can be |
| * either heap or non-heap memory. |
| * |
| * @return the type of this pool. |
| */ |
| String getType(); |
| |
| /** |
| * Returns memory usage statistics for the current memory usage |
| * of the pool. The return value may be <code>null</code> if |
| * this pool is no longer valid. Obtaining these values is |
| * expected to be a relatively quick operation; if this will |
| * instead be an expensive operation to perform, the documentation |
| * of the implementating bean should specify that this is the |
| * case. The values are intended to be an estimate for monitoring |
| * purposes. |
| * |
| * @return the memory usage of the memory pool at present, |
| * or <code>null</code> if this pool is no longer valid. |
| */ |
| MemoryUsage getUsage(); |
| |
| /** |
| * Returns the usage threshold level in bytes. This |
| * value is initially defined by the virtual machine. |
| * |
| * @return the usage threshold in bytes. |
| * @throws UnsupportedOperationException if the usage threshold |
| * is not supported. |
| * @see #getUsageThresholdCount() |
| * @see #isUsageThresholdExceeded() |
| * @see #isUsageThresholdSupported() |
| * @see #setUsageThreshold(long) |
| */ |
| long getUsageThreshold(); |
| |
| /** |
| * Returns the number of times the usage level has matched or |
| * exceeded the usage threshold. |
| * |
| * @return the number of times the usage level has matched |
| * or exceeded the usage threshold. |
| * @throws UnsupportedOperationException if the usage threshold |
| * is not supported. |
| * @see #getUsageThreshold() |
| * @see #isUsageThresholdExceeded() |
| * @see #isUsageThresholdSupported() |
| * @see #setUsageThreshold(long) |
| */ |
| long getUsageThresholdCount(); |
| |
| /** |
| * Returns true if the collection usage level is equal to |
| * or greater than the collection usage threshold. |
| * |
| * @return true if the collection usage threshold has been |
| * matched or exceeded. |
| * @throws UnsupportedOperationException if the collection usage |
| * threshold is not supported. |
| * @see #getCollectionUsageThreshold() |
| * @see #getCollectionUsageThresholdCount() |
| * @see #isCollectionUsageThresholdSupported() |
| * @see #setCollectionUsageThreshold(long) |
| */ |
| boolean isCollectionUsageThresholdExceeded(); |
| |
| /** |
| * Returns true if this memory pool supports a collection usage |
| * level threshold. |
| * |
| * @return true if a collection usage level threshold is supported. |
| * @see #getCollectionUsageThreshold() |
| * @see #getCollectionUsageThresholdCount() |
| * @see #isCollectionUsageThresholdExceeded() |
| * @see #setCollectionUsageThreshold(long) |
| */ |
| boolean isCollectionUsageThresholdSupported(); |
| |
| /** |
| * Returns true if the usage level is equal to |
| * or greater than the usage threshold. |
| * |
| * @return true if the usage threshold has been |
| * matched or exceeded. |
| * @throws UnsupportedOperationException if the usage threshold |
| * is not supported. |
| * @see #getUsageThreshold() |
| * @see #getUsageThresholdCount() |
| * @see #isUsageThresholdSupported() |
| * @see #setUsageThreshold(long) |
| */ |
| boolean isUsageThresholdExceeded(); |
| |
| /** |
| * Returns true if this memory pool supports a usage level threshold. |
| * |
| * @return true if a usage level threshold is supported. |
| * @see #getUsageThreshold() |
| * @see #getUsageThresholdCount() |
| * @see #isUsageThresholdExceeded() |
| * @see #setUsageThreshold(long) |
| */ |
| boolean isUsageThresholdSupported(); |
| |
| /** |
| * Returns true if this memory pool is still valid. A memory pool |
| * becomes invalid when it is removed by the virtual machine and |
| * no longer used. |
| * |
| * @return true if this memory pool is valid. |
| */ |
| boolean isValid(); |
| |
| /** |
| * Resets the peak memory usage level to the current memory usage |
| * level. |
| * |
| * @throws SecurityException if a security manager exists and |
| * denies ManagementPermission("control"). |
| */ |
| void resetPeakUsage(); |
| |
| /** |
| * Sets the collection threshold usage level to the given value. |
| * A value of zero disables the collection threshold. |
| * |
| * @param threshold the new threshold level. |
| * @throws IllegalArgumentException if the threshold hold level |
| * is negative. |
| * @throws UnsupportedOperationException if the collection usage |
| * threshold is not supported. |
| * @throws SecurityException if a security manager exists and |
| * denies ManagementPermission("control"). |
| * @see #getCollectionUsageThreshold() |
| * @see #getCollectionUsageThresholdCount() |
| * @see #isCollectionUsageThresholdExceeded() |
| * @see #isCollectionUsageThresholdSupported() |
| */ |
| void setCollectionUsageThreshold(long threshold); |
| |
| /** |
| * Sets the threshold usage level to the given value. A value of |
| * zero disables the threshold. |
| * |
| * @param threshold the new threshold level. |
| * @throws IllegalArgumentException if the threshold hold level |
| * is negative. |
| * @throws UnsupportedOperationException if the usage threshold |
| * is not supported. |
| * @throws SecurityException if a security manager exists and |
| * denies ManagementPermission("control"). |
| * @see #getUsageThreshold() |
| * @see #getUsageThresholdCount() |
| * @see #isUsageThresholdExceeded() |
| * @see #isUsageThresholdSupported() |
| */ |
| void setUsageThreshold(long threshold); |
| |
| } |
