java - 如何在简单规则中使用变量?
问题描述
我正在使用easy-rulesJSON descriptor
加载规则,并且我想在 easy rules 中使用变量。例如,我有一组规则,其中定义了规则 ID、名称、描述,如下所示actions
[
{
"id": 1,
"name": "Task using Oracle DB",
"description": "Updated comments to update connector",
"priority": 1,
"condition": "user.getTaskData().getTargetConnectorType().contains(\"Oracle\") || user.getTaskData().getSourceConnectorType().contains(\"Oracle\")",
"actions": [
"user.setRuleDetail([\"impacted_feature\":\"Task using Oracle DB\", \"desc\": \"Updated comments to update connector\", \"impact\":\"low\", \"count\":\"Using \"+user.getTaskDetail().getConnBucketData().get(\"Oracle\")+\" connector type\",\"id\":1, \"extra_detail\":\"{\\\"impacted_connectors\\\":[\\\"Oracle\\\"]}\"]);"
]
}
]
这里有以下两件事吗
-> 使用规则name
,description
内部操作?
...
[
{
"id": 1,
"name": "Task using Oracle DB",
"description": "Updated comments to update connector",
"priority": 1,
"condition": "user.getTaskData().getTargetConnectorType().contains(\"Oracle\") || user.getTaskData().getSourceConnectorType().contains(\"Oracle\")",
"actions": [
"user.setRuleDetail([\"impacted_feature\":\"+name+\", \"desc\": \"+description+\", \"impact\":\"low\", \"count\":\"Using \"+user.getTaskDetail().getConnBucketData().get(\"Oracle\")+\" connector type\",\"id\":1, \"extra_detail\":\"{\\\"impacted_connectors\\\":[\\\"Oracle\\\"]}\"]);"
]
}
]
...
-> 在操作下使用变量?
...
"actions": [
"def name = \"Task using Oracle DB\"",
"def desc = \"Updated comments to update connector\"",
"def connector = \"Oracle\"",
"user.setRuleDetail([\"impacted_feature\":\"+name+\", \"desc\": \"+desc+\", \"impact\":\"low\", \"count\":\"Using \"+user.getTaskDetail().getConnBucketData().get(\"Oracle\")+\" connector type\",\"id\":1, \"extra_detail\":\"{\\\"impacted_connectors\\\":[\\\"Oracle\\\"]}\"]);"
]
...
更新
这里我正在初始化MVELRuleFactory
def computeRules(UserData userData) {
try {
Facts facts = new Facts()
facts.put("user", userData)
MVELRuleFactory ruleFactory = new MVELRuleFactory(new JsonRuleDefinitionReader())
Rules rules = ruleFactory.createRules(new FileReader("conf/rules.json"))
//create a default rules engine and fire rules on known facts
RulesEngine rulesEngine = new DefaultRulesEngine()
rulesEngine.fire(rules, facts)
} catch(FileNotFoundException fnfe) {
_errorLogger.error("Error in #computeRules {}", fnfe)
} catch(Exception e) {
_errorLogger.error("Error in #computeRules {}", e)
}
return userData.getRuleDetail()
}
//UserData POJO
@CompileStatic
class UserData {
String orgKey
TaskData taskData
List<Map> ruleDetail
UserData(String orgKey, TaskData taskData) {
this.orgKey = orgKey
this.taskData = taskData
}
String getOrgKey() {
return orgKey
}
void setOrgKey(String orgKey) {
this.orgKey = orgKey
}
TaskData getTaskData() {
return taskData
}
void setTaskData(TaskData taskData) {
this.taskData = taskData
}
List<Map> getRuleDetail() {
return ruleDetail
}
void setRuleDetail(Map ruleData) {
if (this.ruleDetail == null)
this.ruleDetail = []
this.ruleDetail.add(ruleData)
}
@Override
public String toString() {
return "UserData{" +
"orgKey='" + orgKey + '\'' +
", taskData=" + taskData +
", ruleDetail=" + ruleDetail +
'}';
}
}
解决方案
您基本上是在尝试访问条件/操作中的规则信息,或者换句话说,使条件/操作了解规则。您可以使用规则侦听器来做到这一点,该侦听器将规则作为事实放在规则执行之前,然后将其删除。这是一个简单的例子:
public class MyListener implements RuleListener {
@Override
public void beforeExecute(Rule rule, Facts facts) {
facts.put("rule", rule);
}
@Override
public void onSuccess(Rule rule, Facts facts) {
facts.remove("rule");
}
@Override
public void onFailure(Rule rule, Facts facts, Exception exception) {
facts.remove("rule");
}
// implement other methods if needed
}
这里是如何使用它:给定以下规则描述文件rule-aware-action.json
:
[
{
"name": "rule aware action",
"description": "a rule where the action is aware of the rule",
"condition": "true",
"actions": [
"System.out.println(rule.name);"
]
}
]
以下示例打印rule aware action
:
import java.io.FileReader;
import org.jeasy.rules.api.Facts;
import org.jeasy.rules.api.Rule;
import org.jeasy.rules.api.RuleListener;
import org.jeasy.rules.api.Rules;
import org.jeasy.rules.core.DefaultRulesEngine;
import org.jeasy.rules.mvel.MVELRuleFactory;
import org.jeasy.rules.support.reader.JsonRuleDefinitionReader;
public class RuleAwareActionExample {
public static void main(String[] args) throws Exception {
MVELRuleFactory mvelRuleFactory = new MVELRuleFactory(new JsonRuleDefinitionReader());
Rules rules = mvelRuleFactory.createRules(new FileReader("rule-aware-action.json"));
DefaultRulesEngine rulesEngine = new DefaultRulesEngine();
rulesEngine.registerRuleListener(new MyListener());
Facts facts = new Facts();
rulesEngine.fire(rules, facts);
}
}
这意味着该操作能够访问它所属的规则的名称。该示例显示了如何使操作了解其规则,但它也应该适用于条件。
推荐阅读
- cookies - 完整的 cookie 管理系统,asp.net core 3.1 及以上
- r - 在闪亮的日期范围上不留下选定的日期
- maven - 将 jar 文件部署到本地 nginx maven 存储库失败
- python - 我想显示相关> 0.75的列名
- snowflake-cloud-data-platform - 带有与数据摄取和公开相关的 API 的雪花
- javascript - React Bootstrap:将组件添加到模态体
- python - 在使用 beautifulsoup 进行网络抓取时,我无法使用 soup.findAll() 找到相关数据
- algorithm - 用于比较事物并确定它们有多相似的算法和数据结构?
- r - R - 使用 geom_ribbon 以不同颜色为线条下方/上方的区域着色
- mysql - 尝试修复 mysql 安装后收到 Linux“错误:BrokenCount > 0”?