Package dev.frostlake.executor

Class JoinPolicyRules

java.lang.Object

dev.frostlake.executor.JoinPolicyRules

public final class JoinPolicyRules
extends Object

What a JOIN POLICY demands of a query's FROM clause: the protected table must be INNER joined to a DIFFERENT table on an equality between their columns.

Live answers three distinct sentences, which is why this returns one rather than a boolean — no join or an OUTER join is the generic violation, a join that cannot satisfy the constraint (a cross join, a comma join, a constant ON) names the unsatisfied constraint, and a self join is called a potential cross-join. All measured.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	NO_JOIN	The generic refusal: nothing was joined, or the join was an outer one.
static final String	SELF_JOIN	The protected table joined to itself.
static final String	UNSATISFIED	A join is there, but cannot satisfy the policy.

Method Summary

Modifier and Type	Method	Description
static String	violation(FrostlakeParser.TableExpressionContext from, String tableName)	The refusal a FROM clause earns for a table under a join policy, or null when it satisfies one.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

NO_JOIN

public static final String NO_JOIN

The generic refusal: nothing was joined, or the join was an outer one.

See Also:

• Constant Field Values

UNSATISFIED

public static final String UNSATISFIED

A join is there, but cannot satisfy the policy.

See Also:

• Constant Field Values

SELF_JOIN

public static final String SELF_JOIN

The protected table joined to itself.

See Also:

• Constant Field Values

Method Details

violation

public static String violation(FrostlakeParser.TableExpressionContext from,
 String tableName)

The refusal a FROM clause earns for a table under a join policy, or null when it satisfies one.

Parameters:

from - the FROM clause of the select that reads the table

tableName - the protected table's name