DATAGRAPH-1228 - Cleanup Neo4jQueryPlaceholderSupplier.

The PlaceholderSupplier interface has been deleted as it suggest public API where there is none (and where not even a possible injection point exists). Furthermore the index attribute has been removed from the implementation, as the index is supplied externally anyway.

spring-data-neo4j/src/main/java/org/springframework/data/neo4j/repository/query/spel/Neo4jQueryPlaceholderSupplier.java

@@ -15,21 +15,18 @@
  */
 package org.springframework.data.neo4j.repository.query.spel;
 
-public class Neo4jQueryPlaceholderSupplier implements PlaceholderSupplier {
+/**
+ * @author Gerrit Meier
+ * @author Michael J. Simons
+ */
+final class Neo4jQueryPlaceholderSupplier {
 
 	private static final String PLACEHOLDER = "spel_expr";
-	private int index = 0;
-
-	@Override
-	public String nextPlaceholder() {
-		return parameterName(index++);
-	}
 
 	public String parameterName(int index) {
 		return PLACEHOLDER + index;
 	}
 
-	@Override
 	public String decoratePlaceholder(String placeholder) {
 		return "$" + placeholder;
 	}

spring-data-neo4j/src/main/java/org/springframework/data/neo4j/repository/query/spel/PlaceholderSupplier.java

@@ -1,22 +0,0 @@
-/*
- * Copyright 2011-2020 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.
- * You may obtain a copy of the License at
- *
- *      https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.springframework.data.neo4j.repository.query.spel;
-
-interface PlaceholderSupplier {
-	String nextPlaceholder();
-
-	String decoratePlaceholder(String placeholder);
-}