Question

我已经在我的项目中编写了一个自定义内置程序，但我真的不知道如何使用它。我写过两节课。在其中一个中有我使用的内置（使用BaseBuiltin），而在另一个中我注册了新的内置（使用BuiltinRegistry）。

我已经尝试使用默认的内置函数，编写在使用Java从Eclipse可读的文本文件中使用它们的规则。在这种情况下，我没有任何问题。我怎样才能使用我建的内置？我应该在某些文件中导入（或包含）某些内容吗？

Answer 1

首先定义Builtin，通常是通过扩展BaseBuiltin，然后使用BuiltinRegistry.theRegistry.register(Builtin)使其可用于基于Jena规则的推理。

完成上述操作后，您需要实际使用引用Builtin的规则才能触发它。

BuiltinRegistry.theRegistry.register( new BaseBuiltin() {
    @Override
    public String getName() {
        return "example";
    }
    @Override
    public void headAction( final Node[] args, final int length, final RuleContext context ) {
        System.out.println("Head Action: "+Arrays.toString(args));
    }
} );

final String exampleRuleString =
    "[mat1: (?s ?p ?o)\n\t-> print(?s ?p ?o),\n\t   example(?s ?p ?o)\n]"+
    "";
System.out.println(exampleRuleString);

/* I tend to use a fairly verbose syntax for parsing out my rules when I construct them
 * from a string. You can read them from whatever other sources.
 */
final List<Rule> rules;
try( final BufferedReader src = new BufferedReader(new InputStreamReader(new ByteArrayInputStream(exampleRuleString.getBytes()))) ) {
    rules = Rule.parseRules(Rule.rulesParserFromReader(src));
}

/* Construct a reasoner and associate the rules with it  */
final GenericRuleReasoner reasoner = (GenericRuleReasoner) GenericRuleReasonerFactory.theInstance().create(null);
reasoner.setRules(rules);

/* Create & Prepare the InfModel. If you don't call prepare, then
 * rule firings and inference may be deferred until you query the
 * model rather than happening at insertion. This can make you think
 * that your Builtin is not working, when it is.
 */
final InfModel infModel = ModelFactory.createInfModel(reasoner, ModelFactory.createDefaultModel());
infModel.prepare();

/* Add a triple to the graph: 
* [] rdf:type rdfs:Class
*/
infModel.createResource(RDFS.Class);

此代码的输出将为：

正向链规则的字符串
调用打印 Builtin
调用示例 Builtin

......这正是我们所看到的：

[mat1: (?s ?p ?o)
    -> print(?s ?p ?o),
       example(?s ?p ?o)
]
-2b47400d:14593fc1564:-7fff rdf:type rdfs:Class 
Head Action: [-2b47400d:14593fc1564:-7fff, http://www.w3.org/1999/02/22-rdf-syntax-ns#type, http://www.w3.org/2000/01/rdf-schema#Class]

一旦我编写了内置函数，我需要做些什么才能让reasoners知道它？

1 个答案: