com.sun.squawk
Class ObjectMemoryLoader

java.lang.Object
  com.sun.squawk.ObjectMemoryLoader

Direct Known Subclasses:

FlashObjectMemoryLoader

public class ObjectMemoryLoader
extends Object

This class facilitates loading a serialized object graph from a URI and relocating it.

Author:

Doug Simon

Field Summary

protected com.sun.squawk.ObjectMemoryReader

reader The validating reader used to read the components of an object memory from an input stream.

Constructor Summary

protected

ObjectMemoryLoader(com.sun.squawk.ObjectMemoryReader reader, boolean loadIntoReadOnlyMemory) Constructor.

Method Summary

protected int	getHash(byte[] arr) Calculates the hash of an array of bytes.
static int	hash(byte[] arr)
static ObjectMemoryFile	load(DataInputStream dis, String uri, boolean loadIntoReadOnlyMemory) Loads an object memory from a given input stream.
static ObjectMemoryFile	loadHeader(DataInputStream dis, String uri) Loads the header of an object memory file from a given input stream.
protected byte[]	loadMemory(int size) Loads the 'memory' component of the object memory from the input stream.
protected BitSet	loadOopMap(int size) Loads the 'oopmap' component of the object memory from the input stream.
protected Address	relocateMemory(ObjectMemory parent, byte[] buffer, BitSet oopMap) Relocates the memory.
protected void	skipMemoryPadding(String parentURI, int memorySize) Skips the padding that precedes the 'memory' item to ensure that it is word aligned with respect to the start of the object memory file.

Methods inherited from class java.lang.Object

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

Field Detail

reader

protected final com.sun.squawk.ObjectMemoryReader reader

The validating reader used to read the components of an object memory from an input stream.

Constructor Detail

ObjectMemoryLoader

protected ObjectMemoryLoader(com.sun.squawk.ObjectMemoryReader reader,
                             boolean loadIntoReadOnlyMemory)

Constructor.

Parameters:

reader -

loadIntoReadOnlyMemory -

Method Detail

getHash

protected int getHash(byte[] arr)

Calculates the hash of an array of bytes.

Parameters:

arr - the byte array to hash

Returns:

the hash of arr

hash

public static int hash(byte[] arr)

loadHeader

public static ObjectMemoryFile loadHeader(DataInputStream dis,
                                          String uri)

Loads the header of an object memory file from a given input stream.

Parameters:

dis - the data input stream from which to read

uri - a URI identifying the object memory being loaded

Returns:

the ObjectMemoryFile instance encapsulating only the header information in the stream (i.e. the ObjectMemoryFile.objectMemory field is null)

load

public static ObjectMemoryFile load(DataInputStream dis,
                                    String uri,
                                    boolean loadIntoReadOnlyMemory)

Loads an object memory from a given input stream. If the URI describing the source of the input stream corresponds to the URI of an object memory already present in the system, then that object memory is returned instead.

Parameters:

dis - the data input stream from which to read

uri - a URI identifying the object memory being loaded

loadIntoReadOnlyMemory - specifies if the object memory should be put into read-only memory

Returns:

the ObjectMemoryFile instance encapsulating the loaded/resolved object memory

skipMemoryPadding

protected void skipMemoryPadding(String parentURI,
                                 int memorySize)

Skips the padding that precedes the 'memory' item to ensure that it is word aligned with respect to the start of the object memory file.

Parameters:

parentURI - the value of the 'parent_uri' item in the object memory file

memorySize - the value of the 'size' item in the object memory file

loadOopMap

protected BitSet loadOopMap(int size)

Loads the 'oopmap' component of the object memory from the input stream.

Parameters:

size - the size of memory as specified by the 'size' element of the objct memory

Returns:

the bit set encapsulating the oop map

loadMemory

protected byte[] loadMemory(int size)

Loads the 'memory' component of the object memory from the input stream.

Parameters:

size - the size of memory as specified by the 'size' element of the objct memory

Returns:

the contents of the 'memory' component

relocateMemory

protected Address relocateMemory(ObjectMemory parent,
                                 byte[] buffer,
                                 BitSet oopMap)

Relocates the memory.

Parameters:

parent - the loaded/resolved parent object memory

buffer - the contents of the 'memory' component

oopMap - the bit set encapsulating the 'oopmap' component

Returns:

the address of the relocated memory buffer