Package com.day.cq.dam.commons.util

Class MemoryUtil

java.lang.Object

com.day.cq.dam.commons.util.MemoryUtil

public class MemoryUtil
extends java.lang.Object

This class offers some useful memory management functions for asset/image processing

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	MemoryUtil.Callback<T>	Callback throwing IOException and returning some (image) object for tryUntilEnoughMemory(com.day.cq.dam.api.Asset, int, com.day.cq.dam.commons.util.MemoryUtil.Callback)

Field Summary

Fields

Modifier and Type	Field	Description
static long	MIN_CQ_MEMORY_REQUIREMENT	We assume about 100 megs as minimal cq requirement...

Constructor Summary

Constructors

Constructor	Description
MemoryUtil()

Method Summary

Modifier and Type	Method	Description
static long	getExpectedImageMemory(Asset asset)	Calculates the expected image memory consumption.
static boolean	hasEnoughMemory(Asset asset)	Checks if enough memory is available for the asset/image processing Note: it works for images only!
static boolean	hasEnoughSystemMemory(Asset asset)	Checks if the available max.
static long	suggestMaxHeapSize(Asset asset)	Suggests the minimal max.
static <T> T	tryUntilEnoughMemory(Asset asset, int maxTrials, MemoryUtil.Callback<T> callback)	Tries to execute the callback until no memory exception occurs anymore.
static <T> T	tryUntilEnoughMemory(Asset asset, MemoryUtil.Callback<T> callback)	Tries to execute the callback until no memory exception occurs anymore.

Methods inherited from class java.lang.Object

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

Field Detail

MIN_CQ_MEMORY_REQUIREMENT

public static long MIN_CQ_MEMORY_REQUIREMENT

We assume about 100 megs as minimal cq requirement...

Constructor Detail

MemoryUtil

public MemoryUtil()

Method Detail

tryUntilEnoughMemory

public static <T> T tryUntilEnoughMemory(Asset asset,
                                         MemoryUtil.Callback<T> callback)

Tries to execute the callback until no memory exception occurs anymore. Will first check if the asset can be loaded with the given JVM memory settings at all, then go into a loop catching "not enough memory" exceptions and retry until loading worked or a maximum number of retries is reached (100). If it fails, null will be returned.

Type Parameters:

T - return type (image object etc.)

Parameters:

asset - asset to load Java 2D image from

callback - method that actually loads an image involving Java 2D memory, return value will be passed through and returned by this method

Returns:

the value returned by the callback if successful, or null if memory limits prevented loading within a certain number of trials

tryUntilEnoughMemory

public static <T> T tryUntilEnoughMemory(Asset asset,
                                         int maxTrials,
                                         MemoryUtil.Callback<T> callback)

Tries to execute the callback until no memory exception occurs anymore. Will first check if the asset can be loaded with the given JVM memory settings at all, then go into a loop catching "not enough memory" exceptions and retry until loading worked or the given maximum number of retries is reached. If it fails, null will be returned.

Type Parameters:

T - return type (image object etc.)

Parameters:

asset - asset to load Java 2D image from

maxTrials - maximum number of trials, must be > 0

callback - method that actually loads an image involving Java 2D memory, return value will be passed through and returned by this method

Returns:

the value returned by the callback if successful, or null if memory limits prevented loading within a certain number of trials

hasEnoughSystemMemory

public static boolean hasEnoughSystemMemory(Asset asset)

Checks if the available max. memory is enough to process the image

Parameters:

asset - asset to check

Returns:

true either if the check succeeds or the check cannot be performed (no image data available e.g. the asset is not an image) otherwise false

getExpectedImageMemory

public static long getExpectedImageMemory(Asset asset)

Calculates the expected image memory consumption. Bytes required by each pixel are calculated from metadata fields like photoshop:ColorMode or tiff:SamplesPerPixel. If this information can be derived from metadata then it is defaulted to 4.

Parameters:

asset - asset to check

Returns:

the calculated amount or -1 in case the expected memory cannot be calculated

hasEnoughMemory

public static boolean hasEnoughMemory(Asset asset)

Checks if enough memory is available for the asset/image processing Note: it works for images only!

Parameters:

asset - asset to check

Returns:

true either if the check succeeds or the check cannot be performed (no image data available e.g. the asset is not an image) otherwise false

suggestMaxHeapSize

public static long suggestMaxHeapSize(Asset asset)

Suggests the minimal max. heap size

Parameters:

asset - asset to check

Returns:

minimal max. heap size