Package org.eclipse.mat.internal.collectionextract

Class EmptyCollectionExtractor

java.lang.Object

org.eclipse.mat.internal.collectionextract.EmptyCollectionExtractor

All Implemented Interfaces:

ICollectionExtractor

Direct Known Subclasses:

EmptyMapExtractor

public class EmptyCollectionExtractor
extends Object
implements ICollectionExtractor

Known-empty collections

Constructor Summary

Constructors

Constructor	Description
EmptyCollectionExtractor()

Method Summary

Modifier and Type	Method	Description
IObjectArray	extractEntries(IObject coll)	Extracts the array containing the collection content
int[]	extractEntryIds(IObject coll)	Returns the object ids (int) for all objects which are contained in the collection
Integer	getCapacity(IObject coll)	Return the capacity of the collection, if applicable
Double	getFillRatio(IObject coll)	Calculate the fill ratio of a collection
Integer	getNumberOfNotNullElements(IObject collection)	Returns the number of non-null elements in the collection.
Integer	getSize(IObject coll)	Extract the size of the collection.
boolean	hasCapacity()	Check if the collection has capacity, e.g.
boolean	hasExtractableArray()	Return true if the collection array based and the array can be extracted from the heap dump
boolean	hasExtractableContents()	Check if the collection has extractable contents
boolean	hasFillRatio()	Check if fill ratio for the collection can be calculated, i.e.
boolean	hasSize()	Check if the size of the collection can be extracted.

Methods inherited from class java.lang.Object

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

Constructor Details

EmptyCollectionExtractor

public EmptyCollectionExtractor()

Method Details

hasSize

public boolean hasSize()

Description copied from interface: ICollectionExtractor

Check if the size of the collection can be extracted.

Specified by:

hasSize in interface ICollectionExtractor

Returns:

true if ICollectionExtractor.getSize(IObject) could be called

See Also:

• ICollectionExtractor.getSize(IObject)

getSize

public Integer getSize(IObject coll)
                throws SnapshotException

Description copied from interface: ICollectionExtractor

Extract the size of the collection.

Specified by:

getSize in interface ICollectionExtractor

Parameters:

coll - - the collection to find the size of

Returns:

the size, or null if not available

Throws:

SnapshotException - if there is a problem retrieving data from the snapshot

See Also:

• ICollectionExtractor.hasSize()

hasCapacity

public boolean hasCapacity()

Description copied from interface: ICollectionExtractor

Check if the collection has capacity, e.g. ArrayList

Specified by:

hasCapacity in interface ICollectionExtractor

Returns:

true if ICollectionExtractor.getCapacity(IObject) could be called

See Also:

• ICollectionExtractor.getCapacity(IObject)

getCapacity

public Integer getCapacity(IObject coll)
                    throws SnapshotException

Description copied from interface: ICollectionExtractor

Return the capacity of the collection, if applicable

Specified by:

getCapacity in interface ICollectionExtractor

Parameters:

coll - - the collection to find the capacity of

Returns:

the capacity in bytes, or null if unavailable

Throws:

SnapshotException - if there is a problem retrieving data from the snapshot

See Also:

• ICollectionExtractor.hasCapacity()

hasExtractableContents

public boolean hasExtractableContents()

Description copied from interface: ICollectionExtractor

Check if the collection has extractable contents

Specified by:

hasExtractableContents in interface ICollectionExtractor

Returns:

true if ICollectionExtractor.extractEntryIds(IObject) could be called

See Also:

• ICollectionExtractor.extractEntryIds(IObject)

extractEntryIds

public int[] extractEntryIds(IObject coll)
                      throws SnapshotException

Description copied from interface: ICollectionExtractor

Returns the object ids (int) for all objects which are contained in the collection

Specified by:

extractEntryIds in interface ICollectionExtractor

Parameters:

coll - - the collection to find the objects it holds

Returns:

an array of ints which are the object ids.

Throws:

SnapshotException - if there is a problem retrieving data from the snapshot

See Also:

• ICollectionExtractor.hasExtractableContents()

hasExtractableArray

public boolean hasExtractableArray()

Description copied from interface: ICollectionExtractor

Return true if the collection array based and the array can be extracted from the heap dump

Specified by:

hasExtractableArray in interface ICollectionExtractor

Returns:

true if ICollectionExtractor.extractEntries(IObject) could be called

See Also:

• ICollectionExtractor.extractEntries(IObject)

extractEntries

public IObjectArray extractEntries(IObject coll)
                            throws SnapshotException

Description copied from interface: ICollectionExtractor

Extracts the array containing the collection content

Specified by:

extractEntries in interface ICollectionExtractor

Parameters:

coll - - the collection to find the object array holding its contents

Returns:

the backing array for the collection

Throws:

SnapshotException - if there is a problem retrieving data from the snapshot

See Also:

• ICollectionExtractor.hasExtractableArray()

getNumberOfNotNullElements

public Integer getNumberOfNotNullElements(IObject collection)
                                   throws SnapshotException

Description copied from interface: ICollectionExtractor

Returns the number of non-null elements in the collection. Requires hasExtractableContents or hasExtractableArray

Specified by:

getNumberOfNotNullElements in interface ICollectionExtractor

Parameters:

collection - - the collection to find the number of non-null content objects

Returns:

the number of non-null elements, or null if not available

Throws:

SnapshotException

See Also:

• ICollectionExtractor.hasExtractableContents()
• ICollectionExtractor.hasExtractableArray()

hasFillRatio

public boolean hasFillRatio()

Description copied from interface: ICollectionExtractor

Check if fill ratio for the collection can be calculated, i.e. if it has some predefined capacity and actual size.

Specified by:

hasFillRatio in interface ICollectionExtractor

Returns:

true if ICollectionExtractor.getFillRatio(IObject) could be called

See Also:

• ICollectionExtractor.getFillRatio(IObject)

getFillRatio

public Double getFillRatio(IObject coll)
                    throws SnapshotException

Description copied from interface: ICollectionExtractor

Calculate the fill ratio of a collection

Specified by:

getFillRatio in interface ICollectionExtractor

Parameters:

coll - - the collection to find the fill ratio of

Returns:

the fill ratio, between 0.0 and 1.0, or null if unavailable

Throws:

SnapshotException - if there is a problem retrieving data from the snapshot

See Also:

• ICollectionExtractor.hasFillRatio()