com.hazelcast.memory.MemoryStats Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2017, Hazelcast, Inc. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hazelcast.memory;
/**
* Memory statistics for the JVM which current HazelcastInstance belongs to.
*
* Shows total physical/free OS memory, max/committed/used/free heap memory
* and max/committed/used/free native memory.
*
* @see com.hazelcast.memory.GarbageCollectorStats
*/
public interface MemoryStats {
/**
* Returns total physical memory available in OS.
*
* @return total physical memory in bytes.
*/
long getTotalPhysical();
/**
* Returns free physical memory available in OS.
*
* Some operating systems have cached memory regions in which they store hot cached resources like files.
* Cached memory is used for allocations when required. So although this cached region is
* assumed as free, operating systems generally report this region as used not free.
*
* @return free physical memory in bytes.
*/
long getFreePhysical();
/**
* Returns the maximum amount of memory that the JVM will attempt to use in bytes.
*
* @return the maximum amount of memory in bytes.
* @see Runtime#maxMemory()
*/
long getMaxHeap();
/**
* Returns the amount of memory in bytes that is committed for
* the Java virtual machine to use.
*
* @return the amount of committed memory in bytes.
* @see Runtime#totalMemory()
* @see java.lang.management.MemoryUsage#getCommitted()
*/
long getCommittedHeap();
/**
* Returns the amount of used memory in the JVM in bytes.
*
* @return the amount of used memory in bytes
* @see java.lang.management.MemoryUsage#getUsed()
*/
long getUsedHeap();
/**
* Returns the amount of free memory in the JVM in bytes.
*
* @return the amount of free memory in bytes
* @see Runtime#freeMemory()
*/
long getFreeHeap();
/**
* Returns the maximum amount of native memory that current HazelcastInstance
* will attempt to use in bytes.
*
* @return the maximum amount of native memory in bytes.
*/
long getMaxNative();
/**
* Returns the amount of native memory in bytes that is committed for
* current HazelcastInstance to use.
*
* @return the amount of committed native memory in bytes.
*/
long getCommittedNative();
/**
* Returns the amount of used native memory in current HazelcastInstance in bytes.
*
* @return the amount of used native memory in bytes
*/
long getUsedNative();
/**
* Returns the amount of free native memory in current HazelcastInstance in bytes.
*
* @return the amount of free native memory in bytes
*/
long getFreeNative();
/**
* Returns the amount of native memory reserved for metadata. This memory
* is separate and not accounted for by the {@code ...NativeMemory} statistics.
*/
long getMaxMetadata();
/**
* @return amount of used metadata memory
*/
long getUsedMetadata();
/**
* Returns the garbage collector statistics for the JVM
*
* @return GC statistics
*/
GarbageCollectorStats getGCStats();
}