Module openj9.sharedclasses

Package com.ibm.oti.shared

Class SharedClassCacheInfo

java.lang.Object

com.ibm.oti.shared.SharedClassCacheInfo

public class SharedClassCacheInfo
extends Object

SharedClassCacheInfo stores information about a shared class cache and provides methods to retrieve that information.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	ADDRESS_MODE_32	Specifies a 32-bit cache.
static final int	ADDRESS_MODE_64	Specifies a 64-bit cache.
static final int	COMPRESSED_REFS	Specifies a compressedRefs cache.
static final int	COMPRESSED_REFS_UNKNOWN	The compressedRefs mode is unknown for the cache.
static final int	JVMLEVEL_JAVA5	Specifies a Java 5 cache.
static final int	JVMLEVEL_JAVA6	Specifies a Java 6 cache.
static final int	JVMLEVEL_JAVA7	Specifies a Java 7 cache.
static final int	JVMLEVEL_JAVA8	Specifies a Java 8 cache.
static final int	JVMLEVEL_JAVA9	Specifies a Java 9 cache.
static final int	NON_COMPRESSED_REFS	Specifies a non-compressedRefs cache.

Method Summary

Modifier and Type	Method	Description
int	getCacheAddressMode()	Gets the address mode for the shared class cache.
int	getCacheCompressedRefsMode()	Get the compressedRefs mode for the shared class cache.
long	getCacheFreeBytes()	Gets the amount of free bytes in the shared class cache.
int	getCacheJVMLevel()	Gets the JVM level for the shared class cache.
int	getCacheLayer()	Get the layer number for the shared class cache.
String	getCacheName()	Gets the cache name for the shared class cache.
long	getCacheSize()	Gets total usable shared class cache size.
long	getCacheSoftMaxBytes()	Get the soft limit for available space in the cache in bytes.
int	getCacheType()	Check the type of the shared class cache.
Date	getLastDetach()	Gets the time when the shared class cache was last detached.
int	getOSsemid()	Gets the OS semaphore ID associated with the shared class cache.
int	getOSshmid()	Gets the OS shared memory ID associated with the shared class cache.
boolean	isCacheCompatible()	Checks the compatibility of the shared class cache with this JVM.
boolean	isCacheCorrupt()	Checks if the shared class cache is corrupt.
boolean	isCachePersistent()	Deprecated. Use getCacheType() instead.

Methods declared in class java.lang.Object

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

Field Details

JVMLEVEL_JAVA5

public static final int JVMLEVEL_JAVA5

Specifies a Java 5 cache.

See Also:

• Constant Field Values

JVMLEVEL_JAVA6

public static final int JVMLEVEL_JAVA6

Specifies a Java 6 cache.

See Also:

• Constant Field Values

JVMLEVEL_JAVA7

public static final int JVMLEVEL_JAVA7

Specifies a Java 7 cache.

See Also:

• Constant Field Values

JVMLEVEL_JAVA8

public static final int JVMLEVEL_JAVA8

Specifies a Java 8 cache.

See Also:

• Constant Field Values

JVMLEVEL_JAVA9

public static final int JVMLEVEL_JAVA9

Specifies a Java 9 cache.

See Also:

• Constant Field Values

ADDRESS_MODE_32

public static final int ADDRESS_MODE_32

Specifies a 32-bit cache.

See Also:

• Constant Field Values

ADDRESS_MODE_64

public static final int ADDRESS_MODE_64

Specifies a 64-bit cache.

See Also:

• Constant Field Values

COMPRESSED_REFS

public static final int COMPRESSED_REFS

Specifies a compressedRefs cache.

See Also:

• Constant Field Values

NON_COMPRESSED_REFS

public static final int NON_COMPRESSED_REFS

Specifies a non-compressedRefs cache.

See Also:

• Constant Field Values

COMPRESSED_REFS_UNKNOWN

public static final int COMPRESSED_REFS_UNKNOWN

The compressedRefs mode is unknown for the cache.

See Also:

• Constant Field Values

Method Details

getCacheName

public String getCacheName()

Gets the cache name for the shared class cache.

Returns:

Name of the shared class cache.

isCacheCompatible

public boolean isCacheCompatible()

Checks the compatibility of the shared class cache with this JVM.

Returns:

true if cache is compatible with this JVM, false otherwise.

isCachePersistent

@Deprecated
public boolean isCachePersistent()

Deprecated.

Use getCacheType() instead.

Checks if the shared class cache is persistent.

Returns:

true if cache is persistent, false otherwise.

getCacheType

public int getCacheType()

Check the type of the shared class cache.

Returns:

Either SharedClassUtilities.PERSISTENT, SharedClassUtilities.NONPERSISTENT or SharedClassUtilities.SNAPSHOT

getOSshmid

public int getOSshmid()

Gets the OS shared memory ID associated with the shared class cache.

Returns:

A valid value if cache is non-persistent and shared memory id is available, else -1.

getOSsemid

public int getOSsemid()

Gets the OS semaphore ID associated with the shared class cache.

Returns:

A valid value if cache is non-persistent and semaphore id is available, else -1.

getLastDetach

public Date getLastDetach()

Gets the time when the shared class cache was last detached.

Returns:

Date, or null if last detach time is not available.

getCacheJVMLevel

public int getCacheJVMLevel()

Gets the JVM level for the shared class cache. Starting from Java 10, the JVM LEVEL equals to the java version number on which the share class cache is created.

Returns:

A JVMLEVEL constant.

getCacheAddressMode

public int getCacheAddressMode()

Gets the address mode for the shared class cache.

Returns:

Either ADDRESS_MODE_32 or ADDRESS_MODE_64

isCacheCorrupt

public boolean isCacheCorrupt()

Checks if the shared class cache is corrupt.

Returns:

true if the cache is corrupt, false otherwise.

getCacheSize

public long getCacheSize()

Gets total usable shared class cache size. Returns -1 if cache is incompatible.

Returns:

Number of usable bytes in cache.

getCacheFreeBytes

public long getCacheFreeBytes()

Gets the amount of free bytes in the shared class cache. Returns -1 if cache is incompatible.

Returns:

long

getCacheSoftMaxBytes

public long getCacheSoftMaxBytes()

Get the soft limit for available space in the cache in bytes. Returns -1 if cache is incompatible or cache size if it is not set.

Returns:

long

getCacheCompressedRefsMode

public int getCacheCompressedRefsMode()

Get the compressedRefs mode for the shared class cache.

Returns:

Either COMPRESSED_REFS or NON_COMPRESSED_REFS or COMPRESSED_REFS_UNKNOWN

getCacheLayer

public int getCacheLayer()

Get the layer number for the shared class cache.

Returns:

The shared cache layer number or -1 if the shared cache does not have a layer number