A failed attempt to log each about-to-be-deleted node and its properties in Neo4j (for a blog post)

neo4j-tx-event-handling-failed.java

@Test(expected = TransactionFailureException.class)
public void attemptLoggingDeletedNodes() {
    GraphDatabaseService database = new TestGraphDatabaseFactory().newImpermanentDatabase();

    database.registerTransactionEventHandler(new TransactionEventHandler.Adapter<Void>() {
        @Override
        public Void beforeCommit(TransactionData data) throws Exception {
            for (Node deletedNode : data.deletedNodes()) {
                StringBuilder message = new StringBuilder("About to delete node ID ")
                        .append(deletedNode.getId())
                        .append(" ");

                for (String key : deletedNode.getPropertyKeys()) {
                    message.append("key=").append(key);
                    message.append("value=").append(deletedNode.getProperty(key));
                }

                System.out.println(message.toString());
            }

            return null;
        }
    });

    Transaction tx = database.beginTx();
    try {
        database.getNodeById(0).setProperty("test key", "test value");
        tx.success();
    } finally {
        tx.finish();
    }

    tx = database.beginTx();
    try {
        database.getNodeById(0).delete();
        tx.success();
    } finally {
        tx.finish();
    }
}