Java Reference
In-Depth Information
Repeat the previous step to create Java classes called
ImageObject.java
,
ImageSource.java
, and
PMF.java
. Each of these has a specific purpose in the
application:
The
ImageObject
class defines the attributes that you'll store for
each image you upload in the App Engine data store.
•
The
ImageSource
servlet renders your images back to the browser
after retrieving them from the data store.
•
The
ImageTransform
servlet does the processing of the POST
request and stores the files in the data store.
•
The
PMF class
is a
PersistanceManager
class similar to the one
discussed in Chapter 7.
•
Writing the ImageObject Class
Starting with the
ImageObject
class, copy the code from Listing 8-6 to
ImageObject.java
.
This code defines three fields in the data store where you can pass through information
about your image requests.
The first,
id
, is the primary key of type Long.
•
The second,
name
, will store the name of the image file in a string. In
this case, this will be the file name.
•
The third,
ImageObject
, is of type
com.google.appengine.
api.datastore.Blob
. This field will contain a byte array of your
image's source file.
•
Listing 8-6. ImageObject.java
package com.kyleroche.gaeservices;
import java.util.Date;
import javax.jdo.annotations.IdGeneratorStrategy;
import javax.jdo.annotations.IdentityType;
import javax.jdo.annotations.PersistenceCapable;
import javax.jdo.annotations.Persistent;
import javax.jdo.annotations.PrimaryKey;
