WIP: Db migration alterColumn ...

src/main/java/com/avaje/ebean/config/DbMigrationConfig.java

@@ -0,0 +1,42 @@
+package com.avaje.ebean.config;
+
+/**
+ * Configuration for the DB migration processing.
+ */
+public class DbMigrationConfig {
+
+  /**
+   * The application name which is used as the unique code when applying migrations.
+   */
+  private String appName;
+
+  /**
+   * Path where migration
+   */
+  private String resourcePath;
+
+  public String getAppName() {
+    return appName;
+  }
+
+  public void setAppName(String appName) {
+    this.appName = appName;
+  }
+
+  public String getResourcePath() {
+    return resourcePath;
+  }
+
+  public void setResourcePath(String resourcePath) {
+    this.resourcePath = resourcePath;
+  }
+
+  /**
+   * Load the settings from the PropertiesWrapper.
+   */
+  public void loadSettings(PropertiesWrapper properties) {
+
+    appName = properties.get("migration.appName", appName);
+    resourcePath = properties.get("migration.resourcePath", resourcePath);
+  }
+}

src/main/java/com/avaje/ebean/config/ServerConfig.java

@@ -207,6 +207,11 @@ public class ServerConfig {
    */
   private DataSourceConfig dataSourceConfig = new DataSourceConfig();
 
+  /**
+   * The db migration config (migration resource path etc).
+   */
+  private DbMigrationConfig migrationConfig = new DbMigrationConfig();
+
   /**
    * Set to true if the DataSource uses autoCommit.
    * <p>
@@ -502,7 +507,7 @@ public void setPersistBatch(PersistBatch persistBatch) {
   /**
    * Return the JDBC batch mode to use per save(), delete(), insert() or update() request.
    * <p>
-   * This makes sense when a save() or delete() etc cascades and executes multiple child statements. The best caase
+   * This makes sense when a save() or delete() cascades and executes multiple child statements. The best case
    * for this is when saving a master/parent bean this cascade inserts many detail/child beans.
    * </p>
    * <p>
@@ -620,6 +625,20 @@ public void setDatabaseSequenceBatchSize(int databaseSequenceBatchSize) {
     this.databaseSequenceBatchSize = databaseSequenceBatchSize;
   }
 
+  /**
+   * Return the DB migration configuration.
+   */
+  public DbMigrationConfig getMigrationConfig() {
+    return migrationConfig;
+  }
+
+  /**
+   * Set the DB migration configuration.
+   */
+  public void setMigrationConfig(DbMigrationConfig migrationConfig) {
+    this.migrationConfig = migrationConfig;
+  }
+
   /**
    * Return the suffix appended to the base table to derive the view that contains the union
    * of the base table and the history table in order to support asOf queries.
@@ -1856,6 +1875,8 @@ protected void loadAutofetchSettings(PropertiesWrapper p) {
    */
   protected void loadSettings(PropertiesWrapper p) {
 
+    migrationConfig.loadSettings(p);
+
     namingConvention = createNamingConvention(p, namingConvention);
     if (namingConvention != null) {
       namingConvention.loadFromProperties(p);

src/main/java/com/avaje/ebean/dbmigration/DbMigration.java

@@ -0,0 +1,56 @@
+package com.avaje.ebean.dbmigration;
+
+import com.avaje.ebean.Ebean;
+import com.avaje.ebean.EbeanServer;
+import com.avaje.ebean.config.DbMigrationConfig;
+import com.avaje.ebean.dbmigration.model.CurrentModel;
+import com.avaje.ebeaninternal.api.SpiEbeanServer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.File;
+
+/**
+ *
+ */
+public class DbMigration {
+
+  private static final Logger logger = LoggerFactory.getLogger(DbMigration.class);
+
+  private final SpiEbeanServer server;
+
+  private final DbMigrationConfig migrationConfig;
+
+  public DbMigration() {
+    this(Ebean.getDefaultServer());
+  }
+
+  public DbMigration(EbeanServer ebeanServer) {
+    this.server = (SpiEbeanServer) ebeanServer;
+    this.migrationConfig = server.getServerConfig().getMigrationConfig();
+  }
+
+
+
+  public void writeCurrent() {
+
+    CurrentModel currentModel = new CurrentModel(server);
+
+    File writeTo = getWritePath();
+    logger.info("... write to {}", writeTo.getAbsolutePath());
+    currentModel.writeMigration(writeTo);
+  }
+
+  public File getWritePath() {
+    File resourceRootDir = new File("./dbmigration-test/resources");
+
+    // expect to be a relative path
+    String resourcePath = migrationConfig.getResourcePath();
+
+    File path = new File(resourceRootDir, resourcePath);
+    if (!path.exists()) {
+      path.mkdirs();
+    }
+    return new File(path, "migration-current.xml");
+  }
+}

src/main/java/com/avaje/ebean/dbmigration/DbOffline.java

@@ -0,0 +1,37 @@
+package com.avaje.ebean.dbmigration;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ *
+ */
+public class DbOffline {
+
+  private static final Logger logger = LoggerFactory.getLogger(DbOffline.class);
+
+  private static final String KEY = "ebean.dboffline";
+
+  public static final String H2 = "H2";
+
+  public static void setPlatform(String platformName) {
+    System.setProperty(KEY, platformName);
+  }
+
+  public static String getPlatform() {
+    return System.getProperty(KEY);
+  }
+
+  public static void asH2() {
+    setPlatform(H2);
+  }
+
+  public static boolean isSet() {
+    return getPlatform() != null;
+  }
+
+  public static void reset() {
+    System.clearProperty(KEY);
+    logger.info("reset");
+  }
+}

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/BaseDdlHandler.java

@@ -5,6 +5,7 @@
 import com.avaje.ebean.dbmigration.ddlgeneration.platform.DdlNamingConvention;
 import com.avaje.ebean.dbmigration.ddlgeneration.platform.PlatformDdl;
 import com.avaje.ebean.dbmigration.migration.AddColumn;
+import com.avaje.ebean.dbmigration.migration.AlterColumn;
 import com.avaje.ebean.dbmigration.migration.ChangeSet;
 import com.avaje.ebean.dbmigration.migration.CreateTable;
 import com.avaje.ebean.dbmigration.migration.DropColumn;
@@ -23,7 +24,7 @@ public class BaseDdlHandler implements DdlHandler {
 
   public BaseDdlHandler(DdlNamingConvention namingConvention, PlatformDdl platformDdl) {
     this.tableDdl = new BaseTableDdl(namingConvention, platformDdl);
-    this.columnDdl = new BaseColumnDdl();
+    this.columnDdl = new BaseColumnDdl(platformDdl);
   }
 
   @Override
@@ -37,6 +38,8 @@ public void generate(DdlWrite writer, ChangeSet changeSet) throws IOException {
         generate(writer, (AddColumn) change);
       } else if (change instanceof DropColumn) {
         generate(writer, (DropColumn) change);
+      } else if (change instanceof AlterColumn) {
+        generate(writer, (AlterColumn) change);
       }
     }
   }
@@ -56,4 +59,8 @@ public void generate(DdlWrite writer, DropColumn dropColumn) throws IOException
     columnDdl.generate(writer, dropColumn);
   }
 
+  @Override
+  public void generate(DdlWrite writer, AlterColumn alterColumn) throws IOException {
+    columnDdl.generate(writer, alterColumn);
+  }
 }

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/ColumnDdl.java

@@ -1,23 +1,28 @@
 package com.avaje.ebean.dbmigration.ddlgeneration;
 
 import com.avaje.ebean.dbmigration.migration.AddColumn;
+import com.avaje.ebean.dbmigration.migration.AlterColumn;
 import com.avaje.ebean.dbmigration.migration.DropColumn;
 
 import java.io.IOException;
 
 /**
- * Write AddColumn or DropColumn.
+ * Write DDL for AddColumn , DropColumn or AlterColumn.
  */
 public interface ColumnDdl {
 
   /**
-   * Write a AddColumn change.
+   * Write the add column change.
    */
   void generate(DdlWrite writer, AddColumn addColumn) throws IOException;
 
   /**
-   * Write a DropColumn change.
+   * Write the drop column change.
    */
   void generate(DdlWrite writer, DropColumn dropColumn) throws IOException;
 
+  /**
+   * Write the alter column changes.
+   */
+  void generate(DdlWrite writer, AlterColumn alterColumn) throws IOException;
 }

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/DdlHandler.java

@@ -1,6 +1,7 @@
 package com.avaje.ebean.dbmigration.ddlgeneration;
 
 import com.avaje.ebean.dbmigration.migration.AddColumn;
+import com.avaje.ebean.dbmigration.migration.AlterColumn;
 import com.avaje.ebean.dbmigration.migration.ChangeSet;
 import com.avaje.ebean.dbmigration.migration.CreateTable;
 import com.avaje.ebean.dbmigration.migration.DropColumn;
@@ -18,4 +19,7 @@ public interface DdlHandler {
   void generate(DdlWrite writer, AddColumn addColumn) throws IOException;
 
   void generate(DdlWrite writer, DropColumn dropColumn) throws IOException;
-}
+
+  void generate(DdlWrite writer, AlterColumn alterColumn) throws IOException;
+
+}

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/platform/BaseColumnDdl.java

@@ -4,6 +4,7 @@
 import com.avaje.ebean.dbmigration.ddlgeneration.DdlBuffer;
 import com.avaje.ebean.dbmigration.ddlgeneration.DdlWrite;
 import com.avaje.ebean.dbmigration.migration.AddColumn;
+import com.avaje.ebean.dbmigration.migration.AlterColumn;
 import com.avaje.ebean.dbmigration.migration.Column;
 import com.avaje.ebean.dbmigration.migration.DropColumn;
 
@@ -14,6 +15,11 @@
  */
 public class BaseColumnDdl implements ColumnDdl {
 
+  protected final PlatformDdl platformDdl;
+
+  public BaseColumnDdl(PlatformDdl platformDdl) {
+    this.platformDdl = platformDdl;
+  }
 
   @Override
   public void generate(DdlWrite writer, AddColumn addColumn) throws IOException {
@@ -40,6 +46,89 @@ public void generate(DdlWrite writer, DropColumn dropColumn) throws IOException
     // are put into a separate changeSet that is run last
   }
 
+  @Override
+  public void generate(DdlWrite writer, AlterColumn alterColumn) throws IOException {
+
+    if (isTrue(alterColumn.isHistoryExclude())) {
+      historyExcludeColumn(writer, alterColumn);
+    } else if (isFalse(alterColumn.isHistoryExclude())) {
+      historyIncludeColumn(writer, alterColumn);
+    }
+
+    if (hasValue(alterColumn.getOldReferences())) {
+      dropForeignKey(writer, alterColumn);
+    }
+    if (hasValue(alterColumn.getNewReferences())) {
+      addForeignKey(writer, alterColumn);
+    }
+
+    if (isTrue(alterColumn.isUnique())) {
+      addUniqueConstraint(writer, alterColumn);
+    } else if (isFalse(alterColumn.isUnique())) {
+      dropUniqueConstraint(writer, alterColumn);
+    }
+
+    if (isTrue(alterColumn.isUniqueOneToOne())) {
+      addUniqueOneToOneConstraint(writer, alterColumn);
+    } else if (isFalse(alterColumn.isUniqueOneToOne())) {
+      dropUniqueOneToOneConstraint(writer, alterColumn);
+    }
+
+  }
+
+
+
+  protected void addForeignKey(DdlWrite writer, AlterColumn alterColumn) {
+
+  }
+
+  protected void dropForeignKey(DdlWrite writer, AlterColumn alterColumn) {
+
+  }
+
+  protected void dropUniqueOneToOneConstraint(DdlWrite writer, AlterColumn alterColumn) {
+
+  }
+
+  protected void addUniqueOneToOneConstraint(DdlWrite writer, AlterColumn alterColumn) {
+
+  }
+
+  protected void dropUniqueConstraint(DdlWrite writer, AlterColumn alter) throws IOException {
+
+    String tableName = alter.getTableName();
+    String columnName = alter.getColumnName();
+    String uqName = platformDdl.namingConvention.uniqueConstraintName(tableName, columnName, 50);
+
+    writer.apply()
+        .append(platformDdl.dropIndex(uqName, tableName))
+        .endOfStatement();
+  }
+
+  protected void addUniqueConstraint(DdlWrite writer, AlterColumn alter) throws IOException {
+
+    String tableName = alter.getTableName();
+    String columnName = alter.getColumnName();
+    String uqName = platformDdl.namingConvention.uniqueConstraintName(tableName, columnName, 50);
+
+    String[] cols = {columnName};
+    writer.apply()
+        .append(platformDdl.createExternalUniqueForOneToOne(uqName, tableName, cols))
+        .endOfStatement();
+
+    writer.rollbackForeignKeys()
+        .append(platformDdl.dropIndex(uqName, tableName))
+        .endOfStatement();
+  }
+
+  protected void historyIncludeColumn(DdlWrite writer, AlterColumn alterColumn) {
+    platformDdl.historyIncludeColumn(writer, alterColumn);
+  }
+
+  protected void historyExcludeColumn(DdlWrite writer, AlterColumn alterColumn) {
+    platformDdl.historyExcludeColumn(writer, alterColumn);
+  }
+
   protected void alterTableDropColumn(DdlBuffer buffer, String tableName, String columnName) throws IOException {
 
     buffer.append("alter table ").append(tableName)
@@ -63,6 +152,14 @@ protected void alterTableAddColumn(DdlBuffer buffer, String tableName, Column co
   }
 
 
+  protected boolean isFalse(Boolean value) {
+    return value != null && !value;
+  }
+
+  protected boolean isTrue(Boolean value) {
+    return value != null && value;
+  }
+
   protected boolean hasValue(String value) {
     return value != null && !value.trim().isEmpty();
   }