gudusoft.gsqlparser.pp2.render

Class GuardedAstDelegate

Object

gudusoft.gsqlparser.pp2.render.GuardedAstDelegate

All Implemented Interfaces:

RegionRenderer

public class GuardedAstDelegate
extends Object
implements RegionRenderer

The "fast lane" pp2 renderer: hands an AST_OK region's parser to the existing FormatterFactory.pp(parser, opt) machinery, then runs a TokenEquivalence guard on the result to catch any drift between input and output.

Two failure modes

1. pp() throws — possible because pp's mediators / processors traverse arbitrary AST shapes and may break on edge cases the parser accepts but pp does not yet handle. The throwable is logged via PPLogger.error(Throwable) and the delegate returns null so the engine falls through to the next renderer in the chain.
2. pp() silently drifts — produces output that no longer round-trips back to the original token sequence (a comment dropped, a literal rewritten, etc.). The TokenEquivalence.equalsModuloFormatting(java.lang.String, java.lang.String, gudusoft.gsqlparser.pp2.Pp2FormatOptions) guard from S10 detects this. Failures are logged via PPLogger.info(String) and the delegate returns null.

The guard is plan-mandated insurance against pp drift. Plan §13/R4 names this as the explicit mitigation; the guard converts silent bugs into a recoverable fall-through plus a log line.

Inputs the delegate can rely on

The engine only dispatches AST_OK outcomes to this renderer, so the delegate assumes:

• RegionParseOutcome.getStatus() is AST_OK — defended by an explicit guard returning null otherwise.
• RegionParseOutcome.getParser() is non-null and holds exactly one statement (the S12 contract — verified by ParseRecoveryEngineTest.parseAll_outcomeParserRendersOnlyItsRegion).
• RegionParseOutcome.getParsedSql() is the source slice the parser actually saw (with MSSQL/Sybase GO stripped) — the guard compares pp's output against this slice, not the raw range text.

Plan reference: §5.2, §7.3/S13, §7.4/S13, §10.2, §13/R4.

Constructor Summary

Constructors

Constructor and Description
GuardedAstDelegate(EDbVendor vendor) Construct a delegate for the supplied vendor.

Method Summary

Modifier and Type	Method and Description
long	getGuardFailureCount() Count of regions where pp() returned text that failed the guard.
long	getSuccessCount() Count of regions that passed both the parse and the guard.
long	getThrowableCount() Count of regions where pp() threw.
EDbVendor	getVendor()
RendererId	id() Identifier mirrored on RendererId so Pp2FormatResult.Region.getRendererId() reflects which strategy actually produced the text for the region.
protected String	invokePpFormatter(TGSqlParser parser, GFmtOpt opt) Indirect-call seam so tests can subclass and substitute a deterministic stand-in for FormatterFactory.pp().
String	render(RegionParseOutcome outcome, Pp2TokenStream stream, Pp2FormatOptions opts) Render the outcome's region to its final text.
protected String	renderWith(TGSqlParser parser, String inputSlice, Pp2FormatOptions opts) Render via the supplied parser.

Methods inherited from class Object

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

Constructor Detail

GuardedAstDelegate

public GuardedAstDelegate(EDbVendor vendor)

Construct a delegate for the supplied vendor. The vendor is used by the TokenEquivalence guard to tokenise both the input and the output for the comparison.

Throws:

NullPointerException - if vendor is null

Method Detail

getVendor

public EDbVendor getVendor()

getSuccessCount

public long getSuccessCount()

Count of regions that passed both the parse and the guard.

getThrowableCount

public long getThrowableCount()

Count of regions where pp() threw.

getGuardFailureCount

public long getGuardFailureCount()

Count of regions where pp() returned text that failed the guard.

id

public RendererId id()

Description copied from interface: RegionRenderer

Identifier mirrored on RendererId so Pp2FormatResult.Region.getRendererId() reflects which strategy actually produced the text for the region.

Specified by:

id in interface RegionRenderer

render

public String render(RegionParseOutcome outcome,
                     Pp2TokenStream stream,
                     Pp2FormatOptions opts)

Description copied from interface: RegionRenderer

Render the outcome's region to its final text.

Specified by:

render in interface RegionRenderer

Parameters:

outcome - non-null parse outcome for the region. Implementations may assume RegionParseOutcome.getRange() and RegionParseOutcome.getParsedSql() are non-null. RegionParseOutcome.getParser() is non-null only for AST_OK outcomes.

stream - the engine's full Pp2TokenStream for the whole input script (token-based renderers slice into it via the outcome's range token indices)

opts - non-null pp2 options

Returns:

the formatted text for this region, or null (the only sentinel) to signal fall-through to the next renderer in the chain. An empty string is a valid rendering, not a fall-through.

renderWith

protected String renderWith(TGSqlParser parser,
                            String inputSlice,
                            Pp2FormatOptions opts)

Render via the supplied parser. Exposed protected so tests (in a different package) can drive guard-failure scenarios via a subclass with a stand-in invokePpFormatter(gudusoft.gsqlparser.TGSqlParser, gudusoft.gsqlparser.pp.para.GFmtOpt). Not part of the public API; production callers go through render(gudusoft.gsqlparser.pp2.region.RegionParseOutcome, gudusoft.gsqlparser.pp2.token.Pp2TokenStream, gudusoft.gsqlparser.pp2.Pp2FormatOptions).

invokePpFormatter

protected String invokePpFormatter(TGSqlParser parser,
                                   GFmtOpt opt)

Indirect-call seam so tests can subclass and substitute a deterministic stand-in for FormatterFactory.pp(). Production code always goes through the real formatter. protected so the tests in a different package can override.