From e3ae85f8c1d98e3ac90599e5ceac94eb66c234e1 Mon Sep 17 00:00:00 2001
From: Sanne Grinovero <sanne@hibernate.org>
Date: Fri, 12 Oct 2018 22:06:12 +0100
Subject: [PATCH] HHH-13028 Make ASTPrinter caches use less memory

---
 .../hql/internal/ast/util/ASTPrinter.java     | 11 +++++-----
 .../hql/internal/ast/util/ASTUtil.java        | 21 +++++++++++++------
 2 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/hibernate-core/src/main/java/org/hibernate/hql/internal/ast/util/ASTPrinter.java b/hibernate-core/src/main/java/org/hibernate/hql/internal/ast/util/ASTPrinter.java
index fb32e58f4a..a9ed6538ca 100644
--- a/hibernate-core/src/main/java/org/hibernate/hql/internal/ast/util/ASTPrinter.java
+++ b/hibernate-core/src/main/java/org/hibernate/hql/internal/ast/util/ASTPrinter.java
@@ -25,9 +25,11 @@ import antlr.collections.AST;
  * @author Joshua Davis
  * @author Steve Ebersole
  */
-public class ASTPrinter {
+public final class ASTPrinter {
 
-	private final Map<Integer,String> tokenTypeNameCache;
+	// This is a map: array index is the ANTLR Token ID, array value is the name of that token.
+	// There might be gaps in the array (null values) but it's generally quite compact.
+	private final String[] tokenTypeNameCache;
 
 	/**
 	 * Constructs a printer. Package protected: use the constants from {TokenPrinters}
@@ -88,10 +90,9 @@ public class ASTPrinter {
 	 *         or just the integer as a string if none exists.
 	 */
 	public String getTokenTypeName(int type) {
-		final Integer typeInteger = type;
-		String value = tokenTypeNameCache.get( typeInteger );
+		String value = tokenTypeNameCache[type];
 		if ( value == null ) {
-			value = typeInteger.toString();
+			value = Integer.toString( type );
 		}
 		return value;
 	}
diff --git a/hibernate-core/src/main/java/org/hibernate/hql/internal/ast/util/ASTUtil.java b/hibernate-core/src/main/java/org/hibernate/hql/internal/ast/util/ASTUtil.java
index 15e5af195a..3da4f0af12 100644
--- a/hibernate-core/src/main/java/org/hibernate/hql/internal/ast/util/ASTUtil.java
+++ b/hibernate-core/src/main/java/org/hibernate/hql/internal/ast/util/ASTUtil.java
@@ -13,6 +13,8 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.hibernate.HibernateError;
+
 import antlr.ASTFactory;
 import antlr.collections.AST;
 import antlr.collections.impl.ASTArray;
@@ -387,21 +389,28 @@ public final class ASTUtil {
 	 *
 	 * @param tokenTypeInterface The *TokenTypes interface (or implementor of said interface).
 	 *
-	 * @return The generated map.
+	 * @return A compact map int -> tokenName in array format
 	 */
-	public static Map<Integer,String> generateTokenNameCache(Class tokenTypeInterface) {
+	public static String[] generateTokenNameCache(Class tokenTypeInterface) {
 		final Field[] fields = tokenTypeInterface.getFields();
-		Map cache = new HashMap( (int) ( fields.length * .75 ) + 1 );
+		//We try to guess the right size from what we know ANTLR will do;
+		//"guessing" is safe as the three interfaces this is used on are static,
+		//and this is all run at boot so at worst would fail fast.
+		final String[] names = new String[ fields.length + 2 ];
 		for ( final Field field : fields ) {
 			if ( Modifier.isStatic( field.getModifiers() ) ) {
+				int idx = 0;
 				try {
-					cache.put( Integer.valueOf( field.getInt( null ) ), field.getName() );
+					idx = field.getInt( null );
 				}
-				catch (Throwable ignore) {
+				catch (IllegalAccessException e) {
+					throw new HibernateError( "Initialization error", e );
 				}
+				String fieldName = field.getName();
+				names[idx] = fieldName;
 			}
 		}
-		return cache;
+		return names;
 	}
 
 	/**