Examples with VException de.fhg.igd.mongomvcc.VException used on opensource projects

Example 6 with VException

use of de.fhg.igd.mongomvcc.VException in project mongomvcc by igd-geo.

the class MongoDBVBranchTest method createBranchAfterConflict.

/**
	 * Creates another branch after a conflict has happened
	 */
@Test
public void createBranchAfterConflict() {
    VBranch master2 = _db.checkout(VConstants.MASTER);
    putPerson("Max", 3);
    VCollection persons2 = master2.getCollection("persons");
    persons2.insert(_factory.createDocument("name", "Elvis"));
    long masterCid = _master.commit();
    try {
        master2.commit();
        fail("We expect a VException here since the branch's head " + "could not be updated");
    } catch (VException e) {
    //this is what we expect here
    }
    //committing master2 failed, but the commit is still there
    long master2Cid = master2.getHead();
    assertTrue(masterCid != master2Cid);
    _db.createBranch("master2", master2Cid);
    VBranch master = _db.checkout(VConstants.MASTER);
    assertEquals(masterCid, master.getHead());
    master2 = _db.checkout("master2");
    assertEquals(master2Cid, master2.getHead());
}

Example 7 with VException

use of de.fhg.igd.mongomvcc.VException in project mongomvcc by igd-geo.

the class MongoDBVCollectionTest method conflict.

/**
	 * Tests if the database throws an exception if a conflict arises
	 * @throws Exception if everything works as expected
	 */
@Test
public void conflict() throws Exception {
    //obtain collection to get a snapshot of the current database
    _master.getCollection("persons").find();
    assertEquals(0, _master.getCollection("persons").find().size());
    final CountDownLatch latch1 = new CountDownLatch(1);
    final CountDownLatch latch2 = new CountDownLatch(1);
    class ConflictCallable implements Callable<Object> {

        @Override
        public Object call() throws Exception {
            //obtain collection to get a snapshot of the current database
            _master.getCollection("persons").find();
            assertEquals(0, _master.getCollection("persons").find().size());
            latch2.countDown();
            try {
                latch1.await();
            } catch (InterruptedException e) {
                fail();
                throw new RuntimeException(e);
            }
            //insert new person and commit
            putPerson("Peter", 26);
            _master.commit();
            assertEquals(1, _master.getCollection("persons").find().size());
            return null;
        }
    }
    //let other thread make commit based on the same head
    FutureTask<Object> ft1 = new FutureTask<Object>(new ConflictCallable());
    Executor exe = Executors.newCachedThreadPool();
    exe.execute(ft1);
    //wait until other thread has obtained the same branch
    while (!latch2.await(100, TimeUnit.MILLISECONDS)) {
        //check if the other thread threw an exception meanwhile
        if (ft1.isDone()) {
            ft1.get();
        }
    }
    //let other thread commit its result
    latch1.countDown();
    //insert new person and commit
    putPerson("Max", 5);
    //wait for the other thread to exit
    ft1.get();
    //should throw here because of a conflict
    try {
        _master.commit();
    } catch (VException e) {
        //this is what we expect
        return;
    }
    fail("Should have thrown a VException up to now");
}

Example 8 with VException

use of de.fhg.igd.mongomvcc.VException in project mongomvcc by igd-geo.

the class Tree method addBranch.

/**
	 * Adds a named branch. Always waits for the database to fsync before
	 * returning. This guarantees all threads will see the change.
	 * @param name the branch's name
	 * @param headCID the CID of the head commit the branch points to
	 * @throws VException if there already is a branch with the given name or
	 * if the given head CID could not be resolved to an existing commit
	 */
public void addBranch(String name, long headCID) {
    //and then we write
    synchronized (this) {
        //check prerequisites
        if (_branches.findOne(name) != null) {
            throw new VException("A branch with the name " + name + " already exists");
        }
        resolveCommit(headCID);
        //create branch
        DBObject o = new BasicDBObject();
        o.put(MongoDBConstants.ID, name);
        o.put(MongoDBConstants.CID, headCID);
        o.put(ROOT_CID, headCID);
        _branches.insert(o, WriteConcern.FSYNC_SAFE);
    }
}