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<h1>Code Usage</h1>
<h3 id="how-to-use-it-">How to use it ?</h3>
<h4 id="define-a-non-volatile-class">Define a Non-Volatile class:</h4>
<p>```java
/**
* a durable class should be abstract, implement Durable interface and marked with @DurableEntity annotation
*/
@DurableEntity
public abstract class Person<e> implements Durable, Comparable&lt;Person<e>&gt; {
E element; // Generic Type</e></e></p>
<pre><code> /**
* callback for this durable object creation
*/
@Override
public void initializeAfterCreate() {
System.out.println("Initializing After Created");
}
/**
* callback for this durable object recovery
*/
@Override
public void initializeAfterRestore() {
System.out.println("Initializing After Restored");
}
/**
* setup generic info manually to avoid performance penalty
*/
@Override
public void setupGenericInfo(EntityFactoryProxy[] efproxies, GenericField.GType[] gftypes) {
}
@Test
public void testOutput() throws RetrieveDurableEntityError {
System.out.printf("Person %s, Age: %d ( %s ) \n", getName(), getAge(),
null == getMother()? "No Recorded Mother" : "Has Recorded Mother");
}
public int compareTo(Person&lt;E&gt; anotherPerson) {
int ret = 0;
if (0 == ret) ret = getAge().compareTo(anotherPerson.getAge());
if (0 == ret) ret = getName().compareTo(anotherPerson.getName());
return ret;
}
/**
* Getters and Setters for non-volatile fields marked with @DurableGetter and @DurableSetter
*/
@DurableGetter(Id = 1L)
abstract public Short getAge();
@DurableSetter
abstract public void setAge(Short age);
@DurableGetter(Id = 2L)
abstract public String getName() throws RetrieveDurableEntityError;
@DurableSetter
abstract public void setName(String name, boolean destroy) throws OutOfPersistentMemory, RetrieveDurableEntityError;
@DurableGetter(Id = 3L)
abstract public Person&lt;E&gt; getMother() throws RetrieveDurableEntityError;
@DurableSetter
abstract public void setMother(Person&lt;E&gt; mother, boolean destroy) throws RetrieveDurableEntityError;
@DurableGetter(Id = 4L)
abstract public Person&lt;E&gt; getFather() throws RetrieveDurableEntityError;
@DurableSetter
abstract public void setFather(Person&lt;E&gt; mother, boolean destroy) throws RetrieveDurableEntityError; }
</code></pre>
<p>```</p>
<h4 id="use-a-non-volatile-class">Use a non-volatile class:</h4>
<h5 id="setup-an-allocator-for-non-volatile-object-graphs">Setup an allocator for non-volatile object graphs.</h5>
<p>```java
// create an allocator instance
NonVolatileMemAllocator act = new NonVolatileMemAllocator(1024 * 1024 * 8, “./pobj_person.dat”, true);</p>
<pre><code> // fetch handler store capacity from this non-volatile storage managed by this allocator
KEYCAPACITY = act.handlerCapacity();
....
// close it after use
act.close(); ```
</code></pre>
<h5 id="generate-structured-non-volatile-objects">Generate structured non-volatile objects.</h5>
<p>```java
// create a new non-volatile person object from this specific allocator
person = PersonFactory.create(act);</p>
<pre><code> // set attributes
person.setAge((short)rand.nextInt(50));
person.setName(String.format("Name: [%s]", UUID.randomUUID().toString()), true);
// keep this person on non-volatile handler store
act.setHandler(keyidx, person.getHandler());
for (int deep = 0; deep &lt; rand.nextInt(100); ++deep) {
// create another person as mother
mother = PersonFactory.create(act);
mother.setAge((short)(50 + rand.nextInt(50)));
mother.setName(String.format("Name: [%s]", UUID.randomUUID().toString()), true);
// set the person's mother
person.setMother(mother, true);
person = mother;
}
</code></pre>
<p>```</p>
<h5 id="use-the-non-volatile-objects">Use the non-volatile objects</h5>
<p>```java
for (long i = 0; i &lt; KEYCAPACITY; ++i) {</p>
<pre><code> System.out.printf("----------Key %d--------------\n", i);
// iterate non-volatile handlers from handler store of this specific allocator
val = act.getHandler(i);
if (0L == val) {
break;
}
// restore person objects from this specific allocator
Person&lt;Integer&gt; person = PersonFactory.restore(act, val, true);
while (null != person) {
person.testOutput();
// iterate all mother's ancestors
person = person.getMother();
}
}
</code></pre>
<p>```</p>
<h5 id="perform-the-durable-native-computing-eg-printing-wo-packingunpacking-massive-object-graphs">Perform the durable native computing (e.g. printing) w/o packing/unpacking massive object graphs</h5>
<p><code>java
// fetch print service
GeneralComputingService gcsvr = Utils.getGeneralComputingService("print");
// instantiate a value info for a value matrix
ValueInfo vinfo = new ValueInfo();
// instantiate a object stack
List&lt;long[][]&gt; objstack = new ArrayList&lt;long[][]&gt;();
// fill up with all durable object info in order
objstack.add(firstnv.getNativeFieldInfo());
objstack.add(person.getNativeFieldInfo());
// configure the Id stack for each level of durable objects
long[][] fidinfostack = {{2L, 1L}, {0L, 1L}};
// configure the handler of a value matrix
vinfo.handler = handler;
// set translate table from handler's allocator
vinfo.transtable = m_act.getTranslateTable();
// specify the durable type of value
vinfo.dtype = DurableType.SHORT;
// generate frames for this value matri from both stacks
vinfo.frames = Utils.genNativeParamForm(objstack, fidinfostack);
// form an array of value infos
ValueInfo[] vinfos = {vinfo};
// perform the print operation
gcsvr.perform(vinfos);
</code></p>
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