Migrator enhancements

hapi-fhir-jpaserver-migrate/src/main/java/ca/uhn/fhir/jpa/migrate/taskdef/DropColumnTask.java

@@ -0,0 +1,48 @@
+package ca.uhn.fhir.jpa.migrate.taskdef;
+
+/*-
+ * #%L
+ * HAPI FHIR JPA Server - Migration
+ * %%
+ * Copyright (C) 2014 - 2018 University Health Network
+ * %%
+ * 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.
+ * #L%
+ */
+
+import ca.uhn.fhir.jpa.migrate.JdbcUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.sql.SQLException;
+import java.util.Set;
+
+public class DropColumnTask extends BaseTableColumnTypeTask<DropColumnTask> {
+
+	private static final Logger ourLog = LoggerFactory.getLogger(DropColumnTask.class);
+
+
+	@Override
+	public void execute() throws SQLException {
+		Set<String> columnNames = JdbcUtils.getColumnNames(getConnectionProperties(), getTableName());
+		if (!columnNames.contains(getColumnName())) {
+			ourLog.info("Column {} does not exist on table {} - No action performed", getColumnName(), getTableName());
+			return;
+		}
+
+		String sql = "alter table " + getTableName() + " drop column " + getColumnName();
+		ourLog.info("Dropping column {} on table {}", getColumnName(), getTableName());
+		executeSql(sql);
+	}
+
+}

hapi-fhir-jpaserver-migrate/src/main/java/ca/uhn/fhir/jpa/migrate/tasks/api/BaseMigrationTasks.java

@@ -44,14 +44,14 @@ public class BaseMigrationTasks<T extends Enum> {
 
 		List<BaseTask<?>> retVal = new ArrayList<>();
 		for (Object nextVersion : EnumUtils.getEnumList(theFrom.getClass())) {
-			if (((T)nextVersion).ordinal() <= theFrom.ordinal()) {
+			if (((T) nextVersion).ordinal() <= theFrom.ordinal()) {
 				continue;
 			}
-			if (((T)nextVersion).ordinal() > theTo.ordinal()) {
+			if (((T) nextVersion).ordinal() > theTo.ordinal()) {
 				continue;
 			}
 
-			Collection<BaseTask<?>> nextValues = myTasks.get((T)nextVersion);
+			Collection<BaseTask<?>> nextValues = myTasks.get((T) nextVersion);
 			if (nextValues != null) {
 				retVal.addAll(nextValues);
 			}
@@ -120,6 +120,14 @@ public class BaseMigrationTasks<T extends Enum> {
 				return new BuilderAddColumnWithName();
 			}
 
+			public void dropColumn(String theColumnName) {
+				Validate.notBlank(theColumnName);
+				DropColumnTask task = new DropColumnTask();
+				task.setTableName(myTableName);
+				task.setColumnName(theColumnName);
+				addTask(task);
+			}
+
 			public void addTask(BaseTableTask<?> theTask) {
 				theTask.setTableName(myTableName);
 				Builder.this.addTask(theTask);
@@ -165,10 +173,17 @@ public class BaseMigrationTasks<T extends Enum> {
 
 				public class BuilderAddColumnWithNameNullable {
 					public void type(AddColumnTask.ColumnTypeEnum theColumnType) {
+						type(theColumnType, null);
+					}
+
+					public void type(AddColumnTask.ColumnTypeEnum theColumnType, Integer theLength) {
 						AddColumnTask task = new AddColumnTask();
 						task.setColumnName(myColumnName);
 						task.setNullable(myNullable);
 						task.setColumnType(theColumnType);
+						if (theLength != null) {
+							task.setColumnLength(theLength);
+						}
 						addTask(task);
 					}
 				}
@@ -206,7 +221,7 @@ public class BaseMigrationTasks<T extends Enum> {
 							task.setNullable(myNullable);
 							task.setColumnType(theColumnType);
 							addTask(task);
-						} else if (theLength > 0){
+						} else if (theLength > 0) {
 							throw new IllegalArgumentException("Can not specify length for column of type " + theColumnType);
 						}
 					}

hapi-fhir-jpaserver-migrate/src/test/java/ca/uhn/fhir/jpa/migrate/taskdef/DropColumnTest.java

@@ -0,0 +1,32 @@
+package ca.uhn.fhir.jpa.migrate.taskdef;
+
+import ca.uhn.fhir.jpa.migrate.JdbcUtils;
+import org.junit.Test;
+
+import java.sql.SQLException;
+
+import static org.hamcrest.Matchers.containsInAnyOrder;
+import static org.junit.Assert.assertThat;
+
+public class DropColumnTest extends BaseTest {
+
+	@Test
+	public void testDropColumn() throws SQLException {
+		executeSql("create table SOMETABLE (PID bigint not null, TEXTCOL varchar(255))");
+
+		DropColumnTask task = new DropColumnTask();
+		task.setTableName("SOMETABLE");
+		task.setColumnName("TEXTCOL");
+		getMigrator().addTask(task);
+
+		getMigrator().migrate();
+
+		assertThat(JdbcUtils.getColumnNames(getConnectionProperties(), "SOMETABLE"), containsInAnyOrder("PID"));
+
+		// Do it again to make sure there is no error
+		getMigrator().migrate();
+		getMigrator().migrate();
+
+	}
+
+}