14.11. DRL 故障排除的错误消息

1: rule "simple rule"
2:   when
3:     exists Person()
4:     exits Student()  // Must be `exists`
5:   then
6: end

[ERR 101] Line 4:4 no viable alternative at input 'exits' in rule "simple rule"

1: package org.drools.examples;
2: rule    // Must be `rule "rule name"` (or `rule rule_name` if no spacing)
3:   when
4:     Object()
5:   then
6:     System.out.println("A RHS");
7: end

[ERR 101] Line 3:2 no viable alternative at input 'when'

1: rule "simple rule"
2:   when
3:     Student( name == "Andy )  // Must be `"Andy"`
4:   then
5: end

[ERR 101] Line 0:-1 no viable alternative at input '<eof>' in rule "simple rule" in pattern Student

1: rule simple_rule
2:   when
3:     $p : Person(
        // Must be a complete rule statement

[ERR 102] Line 0:-1 mismatched input '<eof>' expecting ')' in rule "simple rule" in pattern Person

1: package org.drools.examples;
2:
3: rule "Wrong syntax"
4:   when
5:     not( Car( ( type == "tesla", price == 10000 ) || ( type == "kia", price == 1000 ) ) from $carList )
       // Must use `&&` operators instead of commas `,`
6:   then
7:     System.out.println("OK");
8: end

[ERR 102] Line 5:36 mismatched input ',' expecting ')' in rule "Wrong syntax" in pattern Car
[ERR 101] Line 5:57 no viable alternative at input 'type' in rule "Wrong syntax"
[ERR 102] Line 5:106 mismatched input ')' expecting 'then' in rule "Wrong syntax"

 1: package nesting;
 2:
 3: import org.drools.compiler.Person
 4: import org.drools.compiler.Address
 5:
 6: Some text  // Must be a valid DRL keyword
 7:
 8: rule "test something"
 9:   when
10:     $p: Person( name=="Michael" )
11:   then
12:     $p.name = "other";
13:     System.out.println(p.name);
14: end

[ERR 103] Line 6:0 rule 'rule_key' failed predicate: {(validateIdentifierKey(DroolsSoftKeywords.RULE))}? in rule

1: rule "simple rule"
2:   when
3:     eval( abc(); )  // Must not use semicolon `;`
4:   then
5: end

[ERR 104] Line 3:4 trailing semi-colon not allowed in rule "simple rule"

1: rule "empty condition"
2:   when
3:     None  // Must remove `None` if condition is empty
4:   then
5:      insert( new Person() );
6: end

[ERR 105] Line 2:2 required (...)+ loop did not match anything at input 'WHEN' in rule "empty condition"