Use ArrayList instead of LinkedList for known size

Issue: SPR-16378

Author: jhoeller

spring-jdbc/src/main/java/org/springframework/jdbc/core/SqlParameter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,6 +16,7 @@
 
 package org.springframework.jdbc.core;
 
+import java.util.ArrayList;
 import java.util.LinkedList;
 import java.util.List;
 
@@ -24,7 +25,7 @@
 /**
  * Object to represent a SQL parameter definition.
  *
- * <p>Parameters may be anonymous, in which case "name" is {@code null}.
+ * <p>Parameters may be anonymous in which case "name" is {@code null}.
  * However, all parameters must define a SQL type according to {@link java.sql.Types}.
  *
  * @author Rod Johnson
@@ -34,16 +35,16 @@
  */
 public class SqlParameter {
 
-	/** The name of the parameter, if any */
+	// The name of the parameter, if any
 	private String name;
 
-	/** SQL type constant from {@code java.sql.Types} */
+	// SQL type constant from {@code java.sql.Types}
 	private final int sqlType;
 
-	/** Used for types that are user-named like: STRUCT, DISTINCT, JAVA_OBJECT, named array types */
+	// Used for types that are user-named like: STRUCT, DISTINCT, JAVA_OBJECT, named array types
 	private String typeName;
 
-	/** The scale to apply in case of a NUMERIC or DECIMAL type, if any */
+	// The scale to apply in case of a NUMERIC or DECIMAL type, if any
 	private Integer scale;
 
 
@@ -177,12 +178,16 @@ public boolean isResultsParameter() {
 	 * to a List of SqlParameter objects as used in this package.
 	 */
 	public static List<SqlParameter> sqlTypesToAnonymousParameterList(int... types) {
-		List<SqlParameter> result = new LinkedList<SqlParameter>();
+		List<SqlParameter> result;
 		if (types != null) {
+			result = new ArrayList<SqlParameter>(types.length);
 			for (int type : types) {
 				result.add(new SqlParameter(type));
 			}
 		}
+		else {
+			result = new LinkedList<SqlParameter>();
+		}
 		return result;
 	}
 

spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/NamedParameterUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,7 +20,6 @@
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.Iterator;
-import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -232,7 +231,6 @@ private static int skipCommentsAndQuotes(char[] statement, int position) {
 					// character sequence ending comment or quote not found
 					return statement.length;
 				}
-
 			}
 		}
 		return position;
@@ -257,8 +255,11 @@ private static int skipCommentsAndQuotes(char[] statement, int position) {
 	 */
 	public static String substituteNamedParameters(ParsedSql parsedSql, SqlParameterSource paramSource) {
 		String originalSql = parsedSql.getOriginalSql();
-		StringBuilder actualSql = new StringBuilder();
 		List<String> paramNames = parsedSql.getParameterNames();
+		if (paramNames.isEmpty()) {
+			return originalSql;
+		}
+		StringBuilder actualSql = new StringBuilder(originalSql.length());
 		int lastIndex = 0;
 		for (int i = 0; i < paramNames.size(); i++) {
 			String paramName = paramNames.get(i);
@@ -282,26 +283,26 @@ public static String substituteNamedParameters(ParsedSql parsedSql, SqlParameter
 						Object entryItem = entryIter.next();
 						if (entryItem instanceof Object[]) {
 							Object[] expressionList = (Object[]) entryItem;
-							actualSql.append("(");
+							actualSql.append('(');
 							for (int m = 0; m < expressionList.length; m++) {
 								if (m > 0) {
 									actualSql.append(", ");
 								}
-								actualSql.append("?");
+								actualSql.append('?');
 							}
-							actualSql.append(")");
+							actualSql.append(')');
 						}
 						else {
-							actualSql.append("?");
+							actualSql.append('?');
 						}
 					}
 				}
 				else {
-					actualSql.append("?");
+					actualSql.append('?');
 				}
 			}
 			else {
-				actualSql.append("?");
+				actualSql.append('?');
 			}
 			lastIndex = endIndex;
 		}
@@ -416,9 +417,10 @@ public static int[] buildSqlTypeArray(ParsedSql parsedSql, SqlParameterSource pa
 	 */
 	public static List<SqlParameter> buildSqlParameterList(ParsedSql parsedSql, SqlParameterSource paramSource) {
 		List<String> paramNames = parsedSql.getParameterNames();
-		List<SqlParameter> params = new LinkedList<SqlParameter>();
+		List<SqlParameter> params = new ArrayList<SqlParameter>(paramNames.size());
 		for (String paramName : paramNames) {
-			params.add(new SqlParameter(paramName, paramSource.getSqlType(paramName), paramSource.getTypeName(paramName)));
+			params.add(new SqlParameter(
+					paramName, paramSource.getSqlType(paramName), paramSource.getTypeName(paramName)));
 		}
 		return params;
 	}