Question

我遇到的问题是，在我将AutoIndex索引设为某个属性之后，我可以添加一个键/值对，并且索引不会显示它在那里。我对neo4j比较陌生，所以我对这个类应该做的概念可能是错误的。测试代码创建一个非永久性图形数据库，用它实例化我的数据服务类，然后创建一个用户。实例化数据服务类时，就是将属性添加到AutoIndex时。你可以在createUser（）函数里面看到，我已经打印出我刚刚创建的用户并且应该在AutoIndex中，但是它打印为null。

这是我正在测试的代码：

@Before
public void setup() throws IOException {
    graphDb = new ImpermanentGraphDatabase();
    Transaction tx = graphDb.beginTx();
    try {
        nA = graphDb.createNode();
        nB = graphDb.createNode();
        packetA = graphDb.createNode();
        packetB = graphDb.createNode();
        dataService = new DataServiceImpl(graphDb);
        tx.success();
    }
    finally
    {
        tx.finish();
    }
}

/****************** Test User Creation Functionality *******************/

@Test
public void createUser() throws ExistsException {
    Transaction tx = graphDb.beginTx();
    try {
        UserWrapper user = (UserWrapper) dataService.createUser(BigInteger.valueOf(1));
        tx.success();
    }
    finally {
        tx.finish();
    }
}

以下是DataServiceImpl中的代码：

/**
 * Node property keys that should be auto-indexed.
 */
private static final Set<String> NODE_KEYS_INDEXABLE = new HashSet<String>(
        Arrays.asList(new String[] { UserWrapper.KEY_IDENTIFIER }));

/**
 * Relationship property keys that should be auto-index.
 */
private static final Set<String> REL_KEYS_INDEXABLE = new HashSet<String>(
        Arrays.asList(new String[] { SentWrapper.TIME_PROP }));

private void initIndices() {
/* Get the auto-indexers */
AutoIndexer<Node> nodeAutoIndexer = this.graphDb.index()
        .getNodeAutoIndexer();

RelationshipAutoIndexer relAutoIndexer = this.graphDb.index()
        .getRelationshipAutoIndexer();

this.updateIndexProperties(nodeAutoIndexer,
        DataServiceImpl.NODE_KEYS_INDEXABLE);

this.nodeIndex = nodeAutoIndexer.getAutoIndex();

this.updateIndexProperties(relAutoIndexer,
        DataServiceImpl.REL_KEYS_INDEXABLE);

this.relIndex = relAutoIndexer.getAutoIndex();
}

/**
 * Sets the indexed properties of an {@link AutoIndexer} to the specified
 * set, removing old properties and adding new ones.
 * 
 * @param autoIndexer
 *            the AutoIndexer to update.
 * @param properties
 *            the properties to be indexed.
 * @return autoIndexer, this given AutoIndexer (useful for chaining calls.)
 */
private <T extends PropertyContainer> AutoIndexer<T> updateIndexProperties(
    AutoIndexer<T> autoIndexer, Set<String> properties) {
Set<String> indexedProps = autoIndexer.getAutoIndexedProperties();
// Remove unneeded properties.
for (String prop : difference(indexedProps, properties)) {
    autoIndexer.stopAutoIndexingProperty(prop);
}

// Add new properties.
for (String prop : difference(properties, indexedProps)) {
    autoIndexer.startAutoIndexingProperty(prop);
}

// Enable the index, if needed.
if (!autoIndexer.isEnabled()) {
    autoIndexer.setEnabled(true);
}

return autoIndexer;
}

public User createUser(BigInteger identifier) throws ExistsException {
    // Verify that user doesn't already exist.
    if (this.nodeIndex.get(UserWrapper.KEY_IDENTIFIER, identifier).getSingle() != null) {
        throw new ExistsException("User with identifier '" + identifier.toString() + "' already exists.");
    }
    // Create new user.
    final Node userNode = graphDb.createNode();
    final User user = new UserWrapper(userNode);
    user.setIdentifier(identifier);

    Node userNode2 = this.nodeIndex.get(UserWrapper.KEY_IDENTIFIER, identifier).getSingle();
    System.out.println(userNode2);

    userParent.getNode().createRelationshipTo(userNode, NodeRelationships.PARENT);

    return user;
}

以下是UserWrapper中的代码：

/**
* Mapping to neo4j key for the identifier property.
*/
//Changed to public in order to test in Test class 
static final String KEY_IDENTIFIER = "identifier";

@Override
public void setIdentifier(BigInteger newIdentity) {
    neo4jNode.setProperty(KEY_IDENTIFIER, newIdentity.toByteArray());
}

Answer 1

你在哪里添加第二个用户？通过运行测试两次？然后ImpermanentGraphDatabase将在第二次运行之前删除所有数据（因为它用于测试）。索引在提交时发生，并在事务期间聚合所有更改，这就是您在tx（userNode2）中看不到它的原因。如果您愿意，可以将此检查添加到测试中（见下文）。

从你的代码中，在你拨打initIndices的地方也看不到它，你能指出一下这个地方吗？还请验证自动索引器是否正确索引正确的属性。

尝试将测试更改为，然后第二次调用应抛出异常：

@Test(expected = ExistsException.class)
public void createUser() throws ExistsException {
    Transaction tx = graphDb.beginTx();
    try {
        UserWrapper user = (UserWrapper) dataService.createUser(BigInteger.valueOf(1));
        tx.success();
    }
    finally {
        tx.finish();
    }
    Node userNode2 = this.graphDb.index().getNodeAutoIndexer().getAutoIndex().get(UserWrapper.KEY_IDENTIFIER, identifier).getSingle();
    assertNotNull(userNode2);

    Transaction tx = graphDb.beginTx();
    try {
        UserWrapper user = (UserWrapper) dataService.createUser(BigInteger.valueOf(1));
        tx.success();
    }
    finally {
        tx.finish();
    }
}

Answer 2

我从迈克尔的回答中间接找到了这个问题的答案。我意识到使用assertNotNull（userNode2）;如果它直接在dataService.createUser（）之后但是如果它在try finally块之后传递则失败。因此，如果我想使用我创建的节点，我需要在创建节点使用它之后创建另一个try finally块。我相信这是因为在调用tx.success（）之前不会将用户添加到索引中，尽管这只是猜测。

neo4j - 属性AutoIndexer不存储值

2 个答案: