DATAJDBC-184 - Support the delimiter character naming strategy.

Original pull request: #49.

src/main/java/org/springframework/data/jdbc/mapping/model/DelimiterNamingStrategy.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright 2018 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.jdbc.mapping.model;
+
+import org.springframework.data.util.ParsingUtils;
+
+/**
+ * The delimiter character implementation of {@link NamingStrategy} with no schema, table based on {@link Class} and
+ * column name based on {@link JdbcPersistentProperty}. The default delimiter is '_'.
+ * This indicate that the default behavior is snake case.
+ *
+ * @author Kazuki Shimizu
+ */
+public class DelimiterNamingStrategy extends DefaultNamingStrategy {
+
+	private final String delimiter;
+
+	/**
+	 * Construct a instance with '_' as delimiter.
+	 * <p>
+	 * This indicate that default is snake case.
+	 */
+	public DelimiterNamingStrategy() {
+		this("_");
+	}
+
+	/**
+	 * Construct a instance with specified delimiter.
+	 *
+	 * @param delimiter a delimiter character
+	 */
+	public DelimiterNamingStrategy(String delimiter) {
+		this.delimiter = delimiter;
+	}
+
+	/**
+	 * Look up the {@link Class}'s simple name after converting to separated word using with {@code delimiter}.
+	 */
+	@Override
+	public String getTableName(Class<?> type) {
+		return ParsingUtils.reconcatenateCamelCase(super.getTableName(type), delimiter);
+	}
+
+	/**
+	 * Look up the {@link JdbcPersistentProperty}'s name after converting to separated word using with {@code delimiter}.
+	 */
+	@Override
+	public String getColumnName(JdbcPersistentProperty property) {
+		return ParsingUtils.reconcatenateCamelCase(super.getColumnName(property), delimiter);
+	}
+
+	/**
+	 * Return the value that adding {@code delimiter} + 'key' for returned value of {@link #getReverseColumnName}.
+	 */
+	@Override
+	public String getKeyColumn(JdbcPersistentProperty property) {
+		return getReverseColumnName(property) + delimiter + "key";
+	}
+
+
+}

src/test/java/org/springframework/data/jdbc/mapping/model/DelimiterNamingStrategyUnitTests.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright 2018 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.jdbc.mapping.model;
+
+import lombok.Data;
+import org.junit.Test;
+import org.springframework.data.annotation.Id;
+import org.springframework.jdbc.core.namedparam.NamedParameterJdbcOperations;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Unit tests for the {@link DelimiterNamingStrategy}.
+ *
+ * @author Kazuki Shimizu
+ */
+public class DelimiterNamingStrategyUnitTests {
+
+	private final DelimiterNamingStrategy target = new DelimiterNamingStrategy();
+
+	private final JdbcPersistentEntity<?> persistentEntity =
+			new JdbcMappingContext(target, mock(NamedParameterJdbcOperations.class), mock(ConversionCustomizer.class))
+					.getRequiredPersistentEntity(DummyEntity.class);
+
+	@Test // DATAJDBC-184
+	public void getTableName() {
+		assertThat(target.getTableName(persistentEntity.getType()))
+				.isEqualTo("dummy_entity");
+	}
+
+	@Test // DATAJDBC-184
+	public void getColumnName() {
+		assertThat(target.getColumnName(persistentEntity.getPersistentProperty("id")))
+				.isEqualTo("id");
+		assertThat(target.getColumnName(persistentEntity.getPersistentProperty("createdAt")))
+				.isEqualTo("created_at");
+		assertThat(target.getColumnName(persistentEntity.getPersistentProperty("dummySubEntities")))
+				.isEqualTo("dummy_sub_entities");
+	}
+
+	@Test // DATAJDBC-184
+	public void getReverseColumnName() {
+		assertThat(target.getReverseColumnName(persistentEntity.getPersistentProperty("dummySubEntities")))
+				.isEqualTo("dummy_entity");
+	}
+
+	@Test // DATAJDBC-184
+	public void getKeyColumn() {
+		assertThat(target.getKeyColumn(persistentEntity.getPersistentProperty("dummySubEntities")))
+				.isEqualTo("dummy_entity_key");
+	}
+
+	@Test // DATAJDBC-184
+	public void getSchema() {
+		assertThat(target.getSchema())
+				.isEmpty();
+	}
+
+	@Test // DATAJDBC-184
+	public void getQualifiedTableName() {
+		assertThat(target.getQualifiedTableName(persistentEntity.getType()))
+				.isEqualTo("dummy_entity");
+	}
+
+	@Data
+	private static class DummyEntity {
+		@Id
+		private int id;
+		private LocalDateTime createdAt;
+		private List<DummySubEntity> dummySubEntities;
+	}
+
+	@Data
+	private static class DummySubEntity {
+		@Id
+		private int id;
+		private LocalDateTime createdAt;
+	}
+
+}