DATACASS-395 - Refactor to immutable converters.

Mutable ResultSet to List/Array converters are now immutable.

spring-cql/src/main/java/org/springframework/cassandra/core/converter/AbstractResultSetConverter.java

@@ -39,23 +39,33 @@ import com.datastax.driver.core.ResultSet;
  * {@link IllegalArgumentException}.
  *
  * @author Matthew T. Adams
+ * @author Mark Paluch
  * @param <T>
  */
 public abstract class AbstractResultSetConverter<T> implements Converter<ResultSet, T> {
 
+	private final static ResultSetToListConverter converter = new ResultSetToListConverter();
+
 	/**
 	 * Converts the given value to this converter's type or throws {@link IllegalArgumentException}.
 	 */
 	protected abstract T doConvertSingleValue(Object object);
 
+	/**
+	 * @return the target type.
+	 */
 	protected abstract Class<?> getType();
 
-	protected ResultSetToListConverter converter = new ResultSetToListConverter();
-
+	/**
+	 * @return surrogate value if the {@link ResultSet} is {@literal null}.
+	 */
 	protected T getNullResultSetValue() {
 		return null;
 	}
 
+	/**
+	 * @return surrogate value if the {@link ResultSet} is {@link ResultSet#isExhausted() exhausted}.
+	 */
 	protected T getExhaustedResultSetValue() {
 		return null;
 	}
@@ -100,8 +110,8 @@ public abstract class AbstractResultSetConverter<T> implements Converter<ResultS
 		return null;
 	}
 
-	protected void doThrow(String string) {
+	void doThrow(String string) {
 		throw new IllegalArgumentException(
-				String.format("can't convert %s to desired type [%s]", string, getType().getName()));
+				String.format("Cannot convert %s to desired type [%s]", string, getType().getName()));
 	}
 }

spring-cql/src/main/java/org/springframework/cassandra/core/converter/ResultSetToArrayConverter.java

@@ -31,7 +31,7 @@ import com.datastax.driver.core.Row;
  */
 public class ResultSetToArrayConverter implements Converter<ResultSet, Object[]> {
 
-	protected Converter<Row, Object[]> rowConverter;
+	private final Converter<Row, Object[]> rowConverter;
 
 	/**
 	 * Create a new {@link ResultSetToArrayConverter} given a row {@link Converter}.
@@ -39,24 +39,9 @@ public class ResultSetToArrayConverter implements Converter<ResultSet, Object[]>
 	 * @param rowConverter must not be {@literal null}.
 	 */
 	public ResultSetToArrayConverter(Converter<Row, Object[]> rowConverter) {
-		setRowConverter(rowConverter);
-	}
-
-	/**
-	 * @return the row {@link Converter}.
-	 */
-	public Converter<Row, Object[]> getRowConverter() {
-		return rowConverter;
-	}
-
-	/**
-	 * Set the row {@link Converter}.
-	 *
-	 * @param rowConverter must not be {@literal null}.
-	 */
-	public void setRowConverter(Converter<Row, Object[]> rowConverter) {
 
 		Assert.notNull(rowConverter, "Converter must not be null");
+
 		this.rowConverter = rowConverter;
 	}
 

spring-cql/src/main/java/org/springframework/cassandra/core/converter/ResultSetToListConverter.java

@@ -32,7 +32,7 @@ import com.datastax.driver.core.Row;
  */
 public class ResultSetToListConverter implements Converter<ResultSet, List<Map<String, Object>>> {
 
-	private Converter<Row, Map<String, Object>> rowConverter;
+	private final Converter<Row, Map<String, Object>> rowConverter;
 
 	/**
 	 * Create a new {@link ResultSetToListConverter} using a default {@link RowToMapConverter}.
@@ -47,22 +47,6 @@ public class ResultSetToListConverter implements Converter<ResultSet, List<Map<S
 	 * @param rowConverter must not be {@literal null}.
 	 */
 	public ResultSetToListConverter(Converter<Row, Map<String, Object>> rowConverter) {
-		setRowConverter(rowConverter);
-	}
-
-	/**
-	 * @return the row to map {@link Converter}.
-	 */
-	public Converter<Row, Map<String, Object>> getRowConverter() {
-		return rowConverter;
-	}
-
-	/**
-	 * Set the the row to map {@link Converter}.
-	 *
-	 * @param rowConverter must not be {@literal null}.
-	 */
-	public void setRowConverter(Converter<Row, Map<String, Object>> rowConverter) {
 
 		Assert.notNull(rowConverter, "Converter must not be null");