DATAJPA-71 - Tweaked AbstractQueryCreator to be more flexible.

AbstractQueryCreator is now more lenient. We're now allowing instantiation without a ParameterAccessor for implementations that don't want to do parameter binding during query creation. We additionally provide a createQuery(Sort) now to allow handing in a dynamic Sort parameter taken from a query method to apply sorting even in case we don't bind parameters directly.

Added a method to Parameters to discover whether we potentially sort dynamically which simply tests for a Sort or Pageable parameter in the method signature.

spring-data-commons-core/src/main/java/org/springframework/data/repository/query/Parameters.java

@@ -183,6 +183,17 @@ public final class Parameters implements Iterable<Parameter> {
 
 		return sortIndex != -1;
 	}
+	
+	
+	/**
+	 * Returns whether we potentially find a {@link Sort} parameter in the parameters.
+	 * 
+	 * @return
+	 */
+	public boolean potentiallySortsDynamically() {
+		
+		return hasSortParameter() || hasPageableParameter();
+	}
 
 
 	/**

spring-data-commons-core/src/main/java/org/springframework/data/repository/query/parser/AbstractQueryCreator.java

@@ -23,11 +23,9 @@ import org.springframework.data.repository.query.ParametersParameterAccessor;
 import org.springframework.data.repository.query.parser.PartTree.OrPart;
 import org.springframework.util.Assert;
 
-
 /**
- * Base class for query creators that create criteria based queries from a
- * {@link PartTree}.
- *
+ * Base class for query creators that create criteria based queries from a {@link PartTree}.
+ * 
  * @param T the actual query type to be created
  * @param S the intermediate criteria type
  * @author Oliver Gierke
@@ -43,43 +41,62 @@ public abstract class AbstractQueryCreator<T, S> {
 	 * via a {@link Sort} parameter.
 	 * 
 	 * @param tree must not be {@literal null}.
-	 * @param parameters
+	 * @param parameters can be {@literal null}.
 	 */
 	public AbstractQueryCreator(PartTree tree, ParameterAccessor parameters) {
 
 		Assert.notNull(tree);
-		Assert.notNull(parameters);
 
 		this.tree = tree;
 		this.parameters = parameters;
 	}
 
+	/**
+	 * Creates a new {@link AbstractQueryCreator} for the given {@link PartTree}. This will cause {@literal null} be
+	 * handed for the {@link Iterator} in the callback methods.
+	 * 
+	 * @param tree must not be {@literal null}.
+	 */
+	public AbstractQueryCreator(PartTree tree) {
+
+		this(tree, null);
+	}
 
 	/**
 	 * Creates the actual query object.
-	 *
+	 * 
 	 * @return
 	 */
 	public T createQuery() {
 
-		Sort treeSort = tree.getSort();
-		Sort sort = treeSort != null ? treeSort : parameters.getSort();
+		Sort dynamicSort = parameters != null ? parameters.getSort() : null;
+		return createQuery(dynamicSort);
+	}
+	
+	/**
+	 * Creates the actual query object applying the given {@link Sort} parameter. Use this method in case you haven't
+	 * provided a {@link ParameterAccessor} in the first place but want to apply dynamic sorting nevertheless.
+	 * 
+	 * @param sort
+	 * @return
+	 */
+	public T createQuery(Sort sort) {
 
-		return complete(createCriteria(tree), sort);
+		Sort sortToUse = sort != null ? sort : tree.getSort();
+		return complete(createCriteria(tree), sortToUse);
 	}
 
-
 	/**
-	 * Actual query building logic. Traverses the {@link PartTree} and invokes
-	 * callback methods to delegate actual criteria creation and concatenation.
-	 *
+	 * Actual query building logic. Traverses the {@link PartTree} and invokes callback methods to delegate actual
+	 * criteria creation and concatenation.
+	 * 
 	 * @param tree
 	 * @return
 	 */
 	private S createCriteria(PartTree tree) {
 
 		S base = null;
-		Iterator<Object> iterator = parameters.iterator();
+		Iterator<Object> iterator = parameters == null ? null : parameters.iterator();
 
 		for (OrPart node : tree) {
 
@@ -87,9 +104,7 @@ public abstract class AbstractQueryCreator<T, S> {
 
 			for (Part part : node) {
 
-				criteria =
-						criteria == null ? create(part, iterator) : and(part,
-								criteria, iterator);
+				criteria = criteria == null ? create(part, iterator) : and(part, criteria, iterator);
 			}
 
 			base = base == null ? criteria : or(base, criteria);
@@ -98,43 +113,37 @@ public abstract class AbstractQueryCreator<T, S> {
 		return base;
 	}
 
-
 	/**
 	 * Creates a new atomic instance of the criteria object.
-	 *
+	 * 
 	 * @param part
 	 * @param iterator
 	 * @return
 	 */
 	protected abstract S create(Part part, Iterator<Object> iterator);
 
-
 	/**
-	 * Creates a new criteria object from the given part and and-concatenates it
-	 * to the given base criteria.
-	 *
+	 * Creates a new criteria object from the given part and and-concatenates it to the given base criteria.
+	 * 
 	 * @param part
-	 * @param base		 will never be {@literal null}.
+	 * @param base will never be {@literal null}.
 	 * @param iterator
 	 * @return
 	 */
 	protected abstract S and(Part part, S base, Iterator<Object> iterator);
 
-
 	/**
 	 * Or-concatenates the given base criteria to the given new criteria.
-	 *
+	 * 
 	 * @param base
 	 * @param criteria
 	 * @return
 	 */
 	protected abstract S or(S base, S criteria);
 
-
 	/**
-	 * Actually creates the query object applying the given criteria object and
-	 * {@link Sort} definition.
-	 *
+	 * Actually creates the query object applying the given criteria object and {@link Sort} definition.
+	 * 
 	 * @param criteria
 	 * @param sort
 	 * @return