Add converters for simple type projections

src/main/java/org/springframework/data/r2dbc/repository/query/RowDataConverter.java

@@ -0,0 +1,220 @@
+/*
+ * Copyright 2019 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
+ *
+ *      http://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.r2dbc.repository.query;
+
+import io.r2dbc.spi.Row;
+import org.springframework.core.convert.converter.Converter;
+import org.springframework.core.convert.converter.ConverterFactory;
+import org.springframework.data.r2dbc.repository.query.RowDataConverter.RowToNumberConverterFactory.RowToOffsetDateTimeConverter;
+import org.springframework.data.r2dbc.repository.query.RowDataConverter.RowToNumberConverterFactory.RowToStringConverter;
+import org.springframework.data.r2dbc.repository.query.RowDataConverter.RowToNumberConverterFactory.RowToUuidConverter;
+import org.springframework.data.r2dbc.repository.query.RowDataConverter.RowToNumberConverterFactory.RowToZonedDateTimeConverter;
+import org.springframework.util.Assert;
+import org.springframework.util.NumberUtils;
+
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.LocalTime;
+import java.time.OffsetDateTime;
+import java.time.ZonedDateTime;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.UUID;
+
+/**
+ * Base class for row data converter.
+ *
+ * @author Hebert Coelho
+ */
+abstract class RowDataConverter {
+    private RowDataConverter() {
+    }
+
+    /**
+     * @return A list of the registered converters
+     */
+    static Collection<Object> getConvertersToRegister() {
+        List<Object> converters = new ArrayList<>();
+
+        converters.add(RowToBooleanConverter.INSTANCE);
+        converters.add(RowToLocalDateConverter.INSTANCE);
+        converters.add(RowToLocalDateTimeConverter.INSTANCE);
+        converters.add(RowToLocalTimeConverter.INSTANCE);
+        converters.add(RowToOffsetDateTimeConverter.INSTANCE);
+        converters.add(RowToStringConverter.INSTANCE);
+        converters.add(RowToUuidConverter.INSTANCE);
+        converters.add(RowToZonedDateTimeConverter.INSTANCE);
+
+        return converters;
+    }
+
+    /**
+     * Simple singleton to convert {@link Row}s to their {@link Boolean} representation.
+     *
+     * @author Hebert Coelho
+     */
+    public enum RowToBooleanConverter implements Converter<Row, Boolean> {
+        INSTANCE;
+
+        @Override
+        public Boolean convert(Row row) {
+            return row.get(0, Boolean.class);
+        }
+    }
+
+    /**
+     * Simple singleton to convert {@link Row}s to their {@link LocalDate} representation.
+     *
+     * @author Hebert Coelho
+     */
+    public enum RowToLocalDateConverter implements Converter<Row, LocalDate> {
+        INSTANCE;
+
+        @Override
+        public LocalDate convert(Row row) {
+            return row.get(0, LocalDate.class);
+        }
+    }
+
+    /**
+     * Simple singleton to convert {@link Row}s to their {@link LocalDateTime} representation.
+     *
+     * @author Hebert Coelho
+     */
+    public enum RowToLocalDateTimeConverter implements Converter<Row, LocalDateTime> {
+        INSTANCE;
+
+        @Override
+        public LocalDateTime convert(Row row) {
+            return row.get(0, LocalDateTime.class);
+        }
+    }
+
+    /**
+     * Simple singleton to convert {@link Row}s to their {@link LocalTime} representation.
+     *
+     * @author Hebert Coelho
+     */
+    public enum RowToLocalTimeConverter implements Converter<Row, LocalTime> {
+        INSTANCE;
+
+        @Override
+        public LocalTime convert(Row row) {
+            return row.get(0, LocalTime.class);
+        }
+    }
+
+    /**
+     * Singleton converter factory to convert the first column of a {@link Row} to a {@link Number}.
+     * <p>
+     * Support Number classes including Byte, Short, Integer, Float, Double, Long, BigInteger, BigDecimal. This class
+     * delegates to {@link NumberUtils#convertNumberToTargetClass(Number, Class)} to perform the conversion.
+     *
+     * @see Byte
+     * @see Short
+     * @see Integer
+     * @see Long
+     * @see java.math.BigInteger
+     * @see Float
+     * @see Double
+     * @see java.math.BigDecimal
+     *
+     * @author Hebert Coelho
+     */
+    public enum RowToNumberConverterFactory implements ConverterFactory<Row, Number> {
+        INSTANCE;
+
+        @Override
+        public <T extends Number> Converter<Row, T> getConverter(Class<T> targetType) {
+            Assert.notNull(targetType, "Target type must not be null");
+            return new RowToNumber<>(targetType);
+        }
+
+        private static final class RowToNumber<T extends Number> implements Converter<Row, T> {
+            private final Class<T> targetType;
+
+            RowToNumber(Class<T> targetType) {
+                this.targetType = targetType;
+            }
+
+            @Override
+            public T convert(Row source) {
+
+                Object object = source.get(0, targetType);
+
+                return (object != null ? NumberUtils.convertNumberToTargetClass((Number) object, this.targetType) : null);
+            }
+        }
+
+        /**
+         * Simple singleton to convert {@link Row}s to their {@link OffsetDateTime} representation.
+         *
+         * @author Hebert Coelho
+         */
+        public enum RowToOffsetDateTimeConverter implements Converter<Row, OffsetDateTime> {
+            INSTANCE;
+
+            @Override
+            public OffsetDateTime convert(Row row) {
+                return row.get(0, OffsetDateTime.class);
+            }
+        }
+
+        /**
+         * Simple singleton to convert {@link Row}s to their {@link String} representation.
+         *
+         * @author Hebert Coelho
+         */
+        public enum RowToStringConverter implements Converter<Row, String> {
+            INSTANCE;
+
+            @Override
+            public String convert(Row row) {
+                return row.get(0, String.class);
+            }
+        }
+
+        /**
+         * Simple singleton to convert {@link Row}s to their {@link UUID} representation.
+         *
+         * @author Hebert Coelho
+         */
+        public enum RowToUuidConverter implements Converter<Row, UUID> {
+            INSTANCE;
+
+            @Override
+            public UUID convert(Row row) {
+                return row.get(0, UUID.class);
+            }
+        }
+
+        /**
+         * Simple singleton to convert {@link Row}s to their {@link ZonedDateTime} representation.
+         *
+         * @author Hebert Coelho
+         */
+        public enum RowToZonedDateTimeConverter implements Converter<Row, ZonedDateTime> {
+            INSTANCE;
+
+            @Override
+            public ZonedDateTime convert(Row row) {
+                return row.get(0, ZonedDateTime.class);
+            }
+        }
+    }
+}

src/test/java/org/springframework/data/r2dbc/repository/query/RowDataConverterTests.java

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+package org.springframework.data.r2dbc.repository.query;
+
+import io.r2dbc.spi.Row;
+import org.junit.Test;
+import org.springframework.core.convert.converter.Converter;
+import org.springframework.data.r2dbc.repository.query.RowDataConverter.RowToBooleanConverter;
+import org.springframework.data.r2dbc.repository.query.RowDataConverter.RowToLocalDateConverter;
+import org.springframework.data.r2dbc.repository.query.RowDataConverter.RowToLocalDateTimeConverter;
+import org.springframework.data.r2dbc.repository.query.RowDataConverter.RowToLocalTimeConverter;
+import org.springframework.data.r2dbc.repository.query.RowDataConverter.RowToNumberConverterFactory;
+import org.springframework.data.r2dbc.repository.query.RowDataConverter.RowToNumberConverterFactory.RowToOffsetDateTimeConverter;
+import org.springframework.data.r2dbc.repository.query.RowDataConverter.RowToNumberConverterFactory.RowToStringConverter;
+import org.springframework.data.r2dbc.repository.query.RowDataConverter.RowToNumberConverterFactory.RowToUuidConverter;
+import org.springframework.data.r2dbc.repository.query.RowDataConverter.RowToNumberConverterFactory.RowToZonedDateTimeConverter;
+
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.LocalTime;
+import java.time.OffsetDateTime;
+import java.time.ZonedDateTime;
+import java.util.UUID;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class RowDataConverterTests {
+    private static final int TOTAL_REGISTERED_CONVERTERS = 8;
+
+    @Test
+    public void isReturningAllCreatedConverts() {
+        assertThat(RowDataConverter.getConvertersToRegister().size())
+            .isEqualTo(TOTAL_REGISTERED_CONVERTERS);
+    }
+
+    @Test
+    public void isConvertingBoolean() {
+        Row row = mock(Row.class);
+        when(row.get(0, Boolean.class)).thenReturn(true);
+
+        assertTrue(RowToBooleanConverter.INSTANCE.convert(row));
+    }
+
+    @Test
+    public void isConvertingLocalDate() {
+        LocalDate now = LocalDate.now();
+        Row row = mock(Row.class);
+        when(row.get(0, LocalDate.class)).thenReturn(now);
+
+        assertThat(RowToLocalDateConverter.INSTANCE.convert(row)).isEqualTo(now);
+    }
+
+    @Test
+    public void isConvertingLocalDateTime() {
+        LocalDateTime now = LocalDateTime.now();
+        Row row = mock(Row.class);
+        when(row.get(0, LocalDateTime.class)).thenReturn(now);
+
+        assertThat(RowToLocalDateTimeConverter.INSTANCE.convert(row)).isEqualTo(now);
+    }
+
+    @Test
+    public void isConvertingLocalTime() {
+        LocalTime now = LocalTime.now();
+        Row row = mock(Row.class);
+        when(row.get(0, LocalTime.class)).thenReturn(now);
+
+        assertThat(RowToLocalTimeConverter.INSTANCE.convert(row)).isEqualTo(now);
+    }
+
+    @Test
+    public void isConvertingOffsetDateTime() {
+        OffsetDateTime now = OffsetDateTime.now();
+        Row row = mock(Row.class);
+        when(row.get(0, OffsetDateTime.class)).thenReturn(now);
+
+        assertThat(RowToOffsetDateTimeConverter.INSTANCE.convert(row)).isEqualTo(now);
+    }
+
+    @Test
+    public void isConvertingString() {
+        String value = "aValue";
+        Row row = mock(Row.class);
+        when(row.get(0, String.class)).thenReturn(value);
+
+        assertThat(RowToStringConverter.INSTANCE.convert(row)).isEqualTo(value);
+    }
+
+    @Test
+    public void isConvertingUUID() {
+        UUID value = UUID.randomUUID();
+        Row row = mock(Row.class);
+        when(row.get(0, UUID.class)).thenReturn(value);
+
+        assertThat(RowToUuidConverter.INSTANCE.convert(row)).isEqualTo(value);
+    }
+
+    @Test
+    public void isConvertingZonedDateTime() {
+        ZonedDateTime now = ZonedDateTime.now();
+        Row row = mock(Row.class);
+        when(row.get(0, ZonedDateTime.class)).thenReturn(now);
+
+        assertThat(RowToZonedDateTimeConverter.INSTANCE.convert(row)).isEqualTo(now);
+    }
+
+    @Test
+    public void isConvertingNumber() {
+        Row row = mock(Row.class);
+        when(row.get(0, Integer.class)).thenReturn(33);
+
+        final Converter<Row, Integer> converter = RowToNumberConverterFactory.INSTANCE.getConverter(Integer.class);
+
+        assertThat(converter.convert(row)).isEqualTo(33);
+    }
+
+    @Test
+    public void isRaisingExceptionForInvalidNumber() {
+        assertThatIllegalArgumentException().isThrownBy(
+            () -> RowToNumberConverterFactory.INSTANCE.getConverter(null)
+        );
+    }
+}