com.google.appengine.api.blobstore
Class BlobInfoFactory

java.lang.Object
  com.google.appengine.api.blobstore.BlobInfoFactory

public class BlobInfoFactory
extends java.lang.Object

BlobInfoFactory provides a trivial interface for retrieving BlobInfo metadata.

BlobInfo metadata is stored in read-only __BlobInfo__ entities in the datastore. This class provides an easy way to access these entities. For more complex queries, you can use the datastore directly.

Field Summary

static java.lang.String	CONTENT_TYPE
static java.lang.String	CREATION
static java.lang.String	FILENAME
static java.lang.String	KIND
static java.lang.String	SIZE

Constructor Summary

BlobInfoFactory()
Creates a BlobInfoFactory that uses the default implementation of DatastoreService.

BlobInfoFactory(DatastoreService datastoreService)
Creates a BlobInfoFactory with the specified implementation of DatastoreService.

Method Summary

BlobInfo	createBlobInfo(Entity entity) Creates a BlobInfo by extracting content from the specified Entity.
BlobInfo	loadBlobInfo(BlobKey blobKey) Loads the BlobInfo metadata for blobKey.
java.util.Iterator<BlobInfo>	queryBlobInfos() Queries for BlobInfo instances, beginning with the BlobKey that appears first in lexicographic order.
java.util.Iterator<BlobInfo>	queryBlobInfosAfter(BlobKey previousBlob) Queries for BlobInfo instances, beginning at the blob following previousBlob in lexicographic order.

Methods inherited from class java.lang.Object

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

Field Detail

KIND

public static final java.lang.String KIND

See Also:

Constant Field Values

CONTENT_TYPE

public static final java.lang.String CONTENT_TYPE

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Constant Field Values

CREATION

public static final java.lang.String CREATION

See Also:

Constant Field Values

FILENAME

public static final java.lang.String FILENAME

See Also:

Constant Field Values

SIZE

public static final java.lang.String SIZE

See Also:

Constant Field Values

Constructor Detail

BlobInfoFactory

public BlobInfoFactory()

Creates a BlobInfoFactory that uses the default implementation of DatastoreService.

BlobInfoFactory

public BlobInfoFactory(DatastoreService datastoreService)

Creates a BlobInfoFactory with the specified implementation of DatastoreService.

Method Detail

loadBlobInfo

public BlobInfo loadBlobInfo(BlobKey blobKey)

Loads the BlobInfo metadata for blobKey. Returns null if no matching blob is found.

queryBlobInfos

public java.util.Iterator<BlobInfo> queryBlobInfos()

Queries for BlobInfo instances, beginning with the BlobKey that appears first in lexicographic order.

queryBlobInfosAfter

public java.util.Iterator<BlobInfo> queryBlobInfosAfter(BlobKey previousBlob)

Queries for BlobInfo instances, beginning at the blob following previousBlob in lexicographic order. If previousBlob is null, the first blob will be returned.

This is useful for displaying discrete pages of blobs.

createBlobInfo

public BlobInfo createBlobInfo(Entity entity)

Creates a BlobInfo by extracting content from the specified Entity.