org.eclipse.jgit.lib
Class ObjectLoader

java.lang.Object
  org.eclipse.jgit.lib.ObjectLoader

Direct Known Subclasses:

ObjectLoader.SmallObject

public abstract class ObjectLoader
extends Object

Base class for a set of loaders for different representations of Git objects. New loaders are constructed for every object.

Nested Class Summary

static class

ObjectLoader.SmallObject Simple loader around the cached byte array.

Constructor Summary

ObjectLoader()

Method Summary

void	copyTo(OutputStream out) Copy this object to the output stream.
byte[]	getBytes() Obtain a copy of the bytes of this object.
byte[]	getBytes(int sizeLimit) Obtain a copy of the bytes of this object.
abstract byte[]	getCachedBytes() Obtain a reference to the (possibly cached) bytes of this object.
byte[]	getCachedBytes(int sizeLimit) Obtain a reference to the (possibly cached) bytes of this object.
abstract long	getSize()
abstract int	getType()
boolean	isLarge()
abstract ObjectStream	openStream() Obtain an input stream to read this object's data.

Methods inherited from class java.lang.Object

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

Constructor Detail

ObjectLoader

public ObjectLoader()

Method Detail

getType

public abstract int getType()

Returns:

Git in pack object type, see Constants.

getSize

public abstract long getSize()

Returns:

size of object in bytes

isLarge

public boolean isLarge()

Returns:

true if this object is too large to obtain as a byte array. Objects over a certain threshold should be accessed only by their openStream() to prevent overflowing the JVM heap.

getBytes

public final byte[] getBytes()
                      throws LargeObjectException

Obtain a copy of the bytes of this object.

Unlike getCachedBytes() this method returns an array that might be modified by the caller.

Returns:

the bytes of this object.

Throws:

LargeObjectException - if the object won't fit into a byte array, because isLarge() returns true. Callers should use openStream() instead to access the contents.

getBytes

public final byte[] getBytes(int sizeLimit)
                      throws LargeObjectException,
                             MissingObjectException,
                             IOException

Obtain a copy of the bytes of this object. If the object size is less than or equal to sizeLimit this method will provide it as a byte array, even if isLarge() is true. This utility is useful for application code that absolutely must have the object as a single contiguous byte array in memory. Unlike getCachedBytes(int) this method returns an array that might be modified by the caller.

Parameters:

sizeLimit - maximum number of bytes to return. If the object is larger than this limit, LargeObjectException will be thrown.

Returns:

the bytes of this object.

Throws:

LargeObjectException - if the object is bigger than sizeLimit, or if OutOfMemoryError occurs during allocation of the result array. Callers should use openStream() instead to access the contents.

MissingObjectException - the object is large, and it no longer exists.

IOException - the object store cannot be accessed.

getCachedBytes

public abstract byte[] getCachedBytes()
                               throws LargeObjectException

Obtain a reference to the (possibly cached) bytes of this object.

This method offers direct access to the internal caches, potentially saving on data copies between the internal cache and higher level code. Callers who receive this reference must not modify its contents. Changes (if made) will affect the cache but not the repository itself.

Returns:

the cached bytes of this object. Do not modify it.

Throws:

LargeObjectException - if the object won't fit into a byte array, because isLarge() returns true. Callers should use openStream() instead to access the contents.

getCachedBytes

public byte[] getCachedBytes(int sizeLimit)
                      throws LargeObjectException,
                             MissingObjectException,
                             IOException

Obtain a reference to the (possibly cached) bytes of this object. If the object size is less than or equal to sizeLimit this method will provide it as a byte array, even if isLarge() is true. This utility is useful for application code that absolutely must have the object as a single contiguous byte array in memory. This method offers direct access to the internal caches, potentially saving on data copies between the internal cache and higher level code. Callers who receive this reference must not modify its contents. Changes (if made) will affect the cache but not the repository itself.

Parameters:

sizeLimit - maximum number of bytes to return. If the object size is larger than this limit and isLarge() is true, LargeObjectException will be thrown.

Returns:

the cached bytes of this object. Do not modify it.

Throws:

LargeObjectException - if the object is bigger than sizeLimit, or if OutOfMemoryError occurs during allocation of the result array. Callers should use openStream() instead to access the contents.

MissingObjectException - the object is large, and it no longer exists.

IOException - the object store cannot be accessed.

openStream

public abstract ObjectStream openStream()
                                 throws MissingObjectException,
                                        IOException

Obtain an input stream to read this object's data.

Returns:

a stream of this object's data. Caller must close the stream when through with it. The returned stream is buffered with a reasonable buffer size.

Throws:

MissingObjectException - the object no longer exists.

IOException - the object store cannot be accessed.

copyTo

public void copyTo(OutputStream out)
            throws MissingObjectException,
                   IOException

Copy this object to the output stream.

For some object store implementations, this method may be more efficient than reading from openStream() into a temporary byte array, then writing to the destination stream.

The default implementation of this method is to copy with a temporary byte array for large objects, or to pass through the cached byte array for small objects.

Parameters:

out - stream to receive the complete copy of this object's data. Caller is responsible for flushing or closing this stream after this method returns.

Throws:

MissingObjectException - the object no longer exists.

IOException - the object store cannot be accessed, or the stream cannot be written to.