Module openj9.dtfj

Package com.ibm.j9ddr.tools.store

Class J9DDRStructureStore

java.lang.Object

com.ibm.j9ddr.tools.store.J9DDRStructureStore

public class J9DDRStructureStore
extends Object

Field Summary

Fields

Modifier and Type	Field	Description
static final String	DEFAULT_SUPERSET_FILE_NAME

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	J9DDRStructureStore()
	J9DDRStructureStore(String databaseDirectory, String supersetFileName)	Create and open the database on the databaseDirectory.

Method Summary

Modifier and Type	Method	Description
void	add(StructureKey key, String structureFileName, boolean inService)	Add newBlob to the database associated to key.
ImageInputStream	get(StructureKey key)
InputStream	getSuperset()	Return a blob that is contains structures and fields that are a superset of all blobs stored in the database.
String	getSuperSetFileName()
boolean	remove(StructureKey key)	Remove the element key from the database.
void	updateSuperset()

Methods declared in class java.lang.Object

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

Field Details

DEFAULT_SUPERSET_FILE_NAME

public static final String DEFAULT_SUPERSET_FILE_NAME

See Also:

• Constant Field Values

Constructor Details

J9DDRStructureStore

protected J9DDRStructureStore()

J9DDRStructureStore

public J9DDRStructureStore(String databaseDirectory,
 String supersetFileName)
                    throws IOException

Create and open the database on the databaseDirectory. Store the current contents of the receiver in the database. Throw an IOException if the directory already exists and does not contain a valid database.

Parameters:

backingDirectory - - Full path to directory

Throws:

IOException - if backingDirectory does not exist or can not be accessed

Method Details

add

public void add(StructureKey key,
 String structureFileName,
 boolean inService)
         throws IOException,
StructureMismatchError

Add newBlob to the database associated to key. If key exists and the associated blob is identical to newBlob no action is taken and no exception is thrown. If key exists but the associated blob is not identical to newBlob throw StructureMismatchError. This is to detect the situation where the structure has changed for a DDR enabled VM but the VM's DDR DDRStructKey has not been changed. If an identical blob with a different key already exists in the database the key is added with a reference to the existing blob. This will save space but will be transparent to the user. QUESTION: Do we want to store a time stamp with the key? On the order of 5000 keys will be added to the database annually. Ideally a partitioning scheme for DDRStructKey name space can be devised such that new keys need only be stored when structure data changes. Parameters may not be null

Parameters:

key - - Key identifying the VM the structure belongs to.

structureFileName - - Full path to a structure file

inService - - True if the structure is for an in-service (non-DDR enabled VM), false otherwise

Throws:

StructureMismatchError - - If key exists in the database but refers to a blob that is NOT identical to blob.

IOException - - If there is a problem storing the blob

updateSuperset

public void updateSuperset()
                    throws IOException

Throws:

IOException

remove

public boolean remove(StructureKey key)
               throws IOException

Remove the element key from the database. Naturally the blob data itself is only removed once all keys that refer to it have been removed

Parameters:

key -

Returns:

true if the key was found and removed or did not exist, false otherwise

Throws:

IOException - - if there was a problem removing the blob

get

public ImageInputStream get(StructureKey key)
                     throws IOException

Parameters:

key -

Returns:

An InputStream open and positioned at the start of the J9DDR structure the blob associated with key. null if key is not contained in the database

Throws:

IOException - - if there is a problem retrieving the blob

getSuperset

public InputStream getSuperset()
                        throws FileNotFoundException

Return a blob that is contains structures and fields that are a superset of all blobs stored in the database. Field offsets are ignored for this operation and the field offsets returned in the blob have no meaning. Only the structure and field names are useful. This API is used for the DDR Structure and Pointer Java code generator

Returns:

an ImageInputStream opened and positioned at the start of a J9DDR structure blob

Throws:

FileNotFoundException

getSuperSetFileName

public String getSuperSetFileName()