#282 - Polishing.

Move query derivation infrastructure to Spring Data Relational. Adapt to newly introduced ValueFunction for deferred value mapping. Use query derivation in integration tests.

Tweak javadoc, add since and author tags, reformat code.

Related ticket: https://jira.spring.io/browse/DATAJDBC-514
Original pull request: #295.

Author: mp911de

Diff for: src/main/java/org/springframework/data/r2dbc/query/QueryMapper.java

@@ -34,19 +34,23 @@
 import org.springframework.data.r2dbc.dialect.MutableBindings;
 import org.springframework.data.r2dbc.dialect.R2dbcDialect;
 import org.springframework.data.r2dbc.mapping.SettableValue;
+import org.springframework.data.relational.core.dialect.Escaper;
 import org.springframework.data.relational.core.mapping.RelationalPersistentEntity;
 import org.springframework.data.relational.core.mapping.RelationalPersistentProperty;
 import org.springframework.data.relational.core.query.CriteriaDefinition;
 import org.springframework.data.relational.core.query.CriteriaDefinition.Comparator;
+import org.springframework.data.relational.core.query.ValueFunction;
 import org.springframework.data.relational.core.sql.*;
 import org.springframework.data.util.ClassTypeInformation;
+import org.springframework.data.util.Pair;
 import org.springframework.data.util.TypeInformation;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 
 /**
- * Maps {@link Criteria} and {@link Sort} objects considering mapping metadata and dialect-specific conversion.
+ * Maps {@link CriteriaDefinition} and {@link Sort} objects considering mapping metadata and dialect-specific
+ * conversion.
  *
  * @author Mark Paluch
  * @author Roman Chigvintsev
@@ -344,7 +348,13 @@ private Condition mapCondition(CriteriaDefinition criteria, MutableBindings bind
 
 			mappedValue = convertValue(settableValue.getValue(), propertyField.getTypeHint());
 			typeHint = getTypeHint(mappedValue, actualType.getType(), settableValue);
+		} else if (criteria.getValue() instanceof ValueFunction) {
 
+			ValueFunction<Object> valueFunction = (ValueFunction<Object>) criteria.getValue();
+			Object value = valueFunction.apply(getEscaper(criteria.getComparator()));
+
+			mappedValue = convertValue(value, propertyField.getTypeHint());
+			typeHint = actualType.getType();
 		} else {
 
 			mappedValue = convertValue(criteria.getValue(), propertyField.getTypeHint());
@@ -354,6 +364,15 @@ private Condition mapCondition(CriteriaDefinition criteria, MutableBindings bind
 		return createCondition(column, mappedValue, typeHint, bindings, criteria.getComparator(), criteria.isIgnoreCase());
 	}
 
+	private Escaper getEscaper(Comparator comparator) {
+
+		if (comparator == Comparator.LIKE || comparator == Comparator.NOT_LIKE) {
+			return dialect.getLikeEscaper();
+		}
+
+		return Escaper.DEFAULT;
+	}
+
 	/**
 	 * Potentially convert the {@link SettableValue}.
 	 *
@@ -376,6 +395,21 @@ protected Object convertValue(@Nullable Object value, TypeInformation<?> typeInf
 			return null;
 		}
 
+		if (value instanceof Pair) {
+
+			Pair<Object, Object> pair = (Pair<Object, Object>) value;
+
+			Object first = convertValue(pair.getFirst(),
+					typeInformation.getActualType() != null ? typeInformation.getRequiredActualType()
+							: ClassTypeInformation.OBJECT);
+
+			Object second = convertValue(pair.getSecond(),
+					typeInformation.getActualType() != null ? typeInformation.getRequiredActualType()
+							: ClassTypeInformation.OBJECT);
+
+			return Pair.of(first, second);
+		}
+
 		if (value instanceof Iterable) {
 
 			List<Object> mapped = new ArrayList<>();
@@ -456,6 +490,19 @@ private Condition createCondition(Column column, @Nullable Object mappedValue, C
 			return condition;
 		}
 
+		if (comparator == Comparator.BETWEEN || comparator == Comparator.NOT_BETWEEN) {
+
+			Pair<Object, Object> pair = (Pair<Object, Object>) mappedValue;
+
+			Expression begin = bind(pair.getFirst(), valueType, bindings,
+					bindings.nextMarker(column.getName().getReference()), ignoreCase);
+			Expression end = bind(mappedValue, valueType, bindings, bindings.nextMarker(column.getName().getReference()),
+					ignoreCase);
+
+			return comparator == Comparator.BETWEEN ? Conditions.between(columnExpression, begin, end)
+					: Conditions.notBetween(columnExpression, begin, end);
+		}
+
 		BindMarker bindMarker = bindings.nextMarker(column.getName().getReference());
 
 		switch (comparator) {
@@ -505,6 +552,10 @@ Field createPropertyField(@Nullable RelationalPersistentEntity<?> entity, SqlIde
 		return entity == null ? new Field(key) : new MetadataBackedField(key, entity, mappingContext);
 	}
 
+	Class<?> getTypeHint(@Nullable Object mappedValue, Class<?> propertyType) {
+		return propertyType;
+	}
+
 	Class<?> getTypeHint(@Nullable Object mappedValue, Class<?> propertyType, SettableValue settableValue) {
 
 		if (mappedValue == null || propertyType.equals(Object.class)) {

Diff for: src/main/java/org/springframework/data/r2dbc/query/UpdateMapper.java

@@ -26,7 +26,9 @@
 import org.springframework.data.r2dbc.dialect.MutableBindings;
 import org.springframework.data.r2dbc.dialect.R2dbcDialect;
 import org.springframework.data.r2dbc.mapping.SettableValue;
+import org.springframework.data.relational.core.dialect.Escaper;
 import org.springframework.data.relational.core.mapping.RelationalPersistentEntity;
+import org.springframework.data.relational.core.query.ValueFunction;
 import org.springframework.data.relational.core.sql.AssignValue;
 import org.springframework.data.relational.core.sql.Assignment;
 import org.springframework.data.relational.core.sql.Assignments;
@@ -134,6 +136,17 @@ private Assignment getAssignment(SqlIdentifier columnName, Object value, Mutable
 			mappedValue = convertValue(settableValue.getValue(), propertyField.getTypeHint());
 			typeHint = getTypeHint(mappedValue, actualType.getType(), settableValue);
 
+		} else if (value instanceof ValueFunction) {
+
+			ValueFunction<Object> valueFunction = (ValueFunction<Object>) value;
+
+			mappedValue = convertValue(valueFunction.apply(Escaper.DEFAULT), propertyField.getTypeHint());
+
+			if (mappedValue == null) {
+				return Assignments.value(column, SQL.nullLiteral());
+			}
+
+			typeHint = actualType.getType();
 		} else {
 
 			mappedValue = convertValue(value, propertyField.getTypeHint());