Package org.openstreetmap.josm.tools

Class MemoryManager

java.lang.Object

org.openstreetmap.josm.tools.MemoryManager

public class MemoryManager
extends java.lang.Object

This class allows all components of JOSM to register reclaimable amounts to memory.

It can be used to hold imagery caches or other data that can be reconstructed form disk/web if required.

Reclaimable storage implementations may be added in the future.

Since:

10588

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private class	MemoryManager.ManualFreeMemoryHandle<T>
static interface	MemoryManager.MemoryHandle<T>	A memory area managed by the MemoryManager.
static class	MemoryManager.NotEnoughMemoryException	This exception is thrown if there is not enough memory for allocating the given object.

Field Summary

Fields

Modifier and Type	Field	Description
private java.util.ArrayList<MemoryManager.MemoryHandle<?>>	activeHandles
private static MemoryManager	INSTANCE
private static long	JOSM_CORE_FOOTPRINT	assumed minimum JOSM memory footprint

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	MemoryManager()

Method Summary

Modifier and Type	Method	Description
<T> MemoryManager.MemoryHandle<T>	allocateMemory(java.lang.String name, long maxBytes, java.util.function.Supplier<T> factory)	Allocates a basic, fixed memory size.
long	getAvailableMemory()	Gets the memory that is considered free.
static MemoryManager	getInstance()	Get the global memory manager instance.
long	getMaxMemory()	Gets the maximum amount of memory available for use in this manager.
boolean	isAvailable(long maxBytes)	Check if that memory is available
protected java.util.List<MemoryManager.MemoryHandle<?>>	resetState()	Reset the state of this manager to the default state.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

JOSM_CORE_FOOTPRINT

private static final long JOSM_CORE_FOOTPRINT

assumed minimum JOSM memory footprint

See Also:

Constant Field Values

INSTANCE

private static final MemoryManager INSTANCE

activeHandles

private final java.util.ArrayList<MemoryManager.MemoryHandle<?>> activeHandles

Constructor Detail

MemoryManager

protected MemoryManager()

Method Detail

allocateMemory

public <T> MemoryManager.MemoryHandle<T> allocateMemory(java.lang.String name,
                                                        long maxBytes,
                                                        java.util.function.Supplier<T> factory)
                                                 throws MemoryManager.NotEnoughMemoryException

Allocates a basic, fixed memory size.

If there is enough free memory, the factory is used to procude one element which is then returned as memory handle.

You should invoke MemoryManager.MemoryHandle.free() if you do not need that handle any more.

Type Parameters:

T - The content type of the memory-

Parameters:

name - A name for the memory area. Only used for debugging.

maxBytes - The maximum amount of bytes the content may have

factory - The factory to use to procude the content if there is sufficient memory.

Returns:

A memory handle to the content.

Throws:

MemoryManager.NotEnoughMemoryException - If there is not enough memory to allocate.

isAvailable

public boolean isAvailable(long maxBytes)

Check if that memory is available

Parameters:

maxBytes - The memory to check for

Returns:

true if that memory is available.

getMaxMemory

public long getMaxMemory()

Gets the maximum amount of memory available for use in this manager.

Returns:

The maximum amount of memory.

getAvailableMemory

public long getAvailableMemory()

Gets the memory that is considered free.

Returns:

The memory that can be used for new allocations.

getInstance

public static MemoryManager getInstance()

Get the global memory manager instance.

Returns:

The memory manager.

resetState

protected java.util.List<MemoryManager.MemoryHandle<?>> resetState()

Reset the state of this manager to the default state.

Returns:

true if there were entries that have been reset.