Neo4j3.5学习笔记——中断正在运行的transaction

跟着官网代码学习.jpg–jdk 1.8.0 & neo4j 3.5
https://neo4j.com/docs/java-reference/current/java-embedded/

通过另一个线程终止long-running的transaction。

1：建立一个long-running transaction：在数据库中建立一个无限二进制树。

public String run() throws IOException {
        FileUtils.deleteRecursively(databaseDirectory);

        graphDb = new GraphDatabaseFactory().newEmbeddedDatabase(databaseDirectory);
        RelationshipType relType = RelationshipType.withName("CHILD");
        Queue<Node> nodes = new LinkedList<>();
        int depth = 1;

        try(Transaction tx = graphDb.beginTx()) {
            Node rootNode = graphDb.createNode();
            nodes.add(rootNode);

            Terminator terminator = new Terminator(tx);
            terminator.terminateAfter(5000);

            for(;true;depth++) {
                int nodesToExpand = nodes.size();
                for (int i=0; i<nodesToExpand; ++i) {
                    Node parent = nodes.remove();
                    Node left = graphDb.createNode();
                    Node right = graphDb.createNode();

                    parent.createRelationshipTo(left, relType);
                    parent.createRelationshipTo(right, relType);

                    nodes.add(left);
                    nodes.add(right);
                }
            }
        }
        catch (TransactionTerminatedException ignored) {
            return String.format("Created tree up to depth %s in 5 sec", depth);
        }
        finally {
            graphDb.shutdown();
        }
    }

2：从另一个Thread中断transaction

• 由于transaction是被中断的，实际上并没有对数据进行任何更改，最后结果就像没有执行任何操作一样；
• （官网代码中建立了Terminator类，例中的Terminator{}作为构造器，初始化tx的值；）
• 新Thread先睡millis的长度，然后通过tx.terminate()实现中断。

Executors.newSingleThreadExecutor().submit(new Runnable() {
                @Override
                public void run() {
                    long startTime = System.currentTimeMillis();
                    do {
                        try {
                            Thread.sleep(millis);
                        }
                        catch(InterruptedException ignored) {
                            //terminated while sleeping
                        }
                    }
                    while((System.currentTimeMillis() - startTime) < millis);

                    tx.terminate();
                }
            });

3. 具体代码见： https://github.com/Amy996bbq/Neo4j/blob/master/learn/TerminateTransaction.java