在 Eclipse 中构建 Drools 4 项目时出现问题

发布于 2024-08-05 01:38:01 字数 194 浏览 8 评论 0原文

我在编译 drools 4 项目时遇到问题。我在规则文件中收到错误，指出

Only a type can be imported. <<MyClassName>> resolves to a package

增量编译器因此无法工作。如何修复这些错误或让 Eclipse 忽略它们？

原文

I'm having trouble compiling a drools 4 project. I'm getting errors in the rules file saying

Only a type can be imported. <<MyClassName>> resolves to a package

The incremental compiler isn't working because of this. How do I fix the errors or get eclipse to ignore them?

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如若梦似彩虹 2024-08-12 01:38:01

从 drools 3.06 迁移到 4.0.7，那么你使用的 eclipse 和 drools 是什么版本？

这可能与类路径问题有关：

使用调试器我意识到 Drools PackageBuilder 尝试从加载类

Thread.currentThread().getContextClassLoader();

此ClassLoader不包含我的代理类！甚至系统类加载器也不包含我的类。

解决方案是：

不必创建普通的 PackageBuilder 和 RuleBase 实例，而是必须使用 PackageBuilderConfiguration 和 RuleBaseConfiguration 创建它们> 两者都配置了当前的classLoader：

ClassLoader classLoader = this.getClass().getClassLoader();

PackageBuilderConfiguration configuration = new PackageBuilderConfiguration();
configuration.setClassLoader(classLoader);

PackageBuilder builder = new PackageBuilder(configuration);

builder.addPackageFromDrl(source);

RuleBaseConfiguration ruleBaseConfiguration = new RuleBaseConfiguration();
ruleBaseConfiguration.setClassLoader(classLoader);

ruleBase = RuleBaseFactory.newRuleBase(ruleBaseConfiguration);
ruleBase.addPackage(builder.getPackage());

This issue was mentioned for a migration from drools 3.06 to 4.0.7, so what version of eclipse and drools are you using?

This might be related to a classpath issue:

Using the debugger I realized that the Drools PackageBuilder tried to load the classes from the

Thread.currentThread().getContextClassLoader();

This ClassLoader does not contain my agent classes! Even the system class loader does not contain my classes.

The solution was:

Instead of creating plain PackageBuilder and RuleBase instances, one has to create them with a PackageBuilderConfiguration and a RuleBaseConfiguration both with the current classLoader configured:

ClassLoader classLoader = this.getClass().getClassLoader();

PackageBuilderConfiguration configuration = new PackageBuilderConfiguration();
configuration.setClassLoader(classLoader);

PackageBuilder builder = new PackageBuilder(configuration);

builder.addPackageFromDrl(source);

RuleBaseConfiguration ruleBaseConfiguration = new RuleBaseConfiguration();
ruleBaseConfiguration.setClassLoader(classLoader);

ruleBase = RuleBaseFactory.newRuleBase(ruleBaseConfiguration);
ruleBase.addPackage(builder.getPackage());

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