content: /*****************************************************************
   *   Licensed to the Apache Software Foundation (ASF) under one
   *  or more contributor license agreements.  See the NOTICE file
   *  distributed with this work for additional information
   *  regarding copyright ownership.  The ASF licenses this file
   *  to you 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
   *
   *    https://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.apache.cayenne.dbsync.merge.token.model;
  
  import org.apache.cayenne.dbsync.merge.context.MergerContext;
  import org.apache.cayenne.dbsync.merge.factory.MergerTokenFactory;
  import org.apache.cayenne.dbsync.merge.token.MergerToken;
  import org.apache.cayenne.map.DbAttribute;
  import org.apache.cayenne.map.DbEntity;
  import org.apache.cayenne.map.DbJoin;
  import org.apache.cayenne.map.DbRelationship;
  import org.apache.cayenne.map.ObjAttribute;
  import org.apache.cayenne.map.ObjEntity;
  
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * A {@link MergerToken} to remove a {@link DbAttribute} from a {@link DbEntity}.
   * 
   */
  public class DropColumnToModel extends AbstractToModelToken.EntityAndColumn {
  
      public DropColumnToModel(DbEntity entity, DbAttribute column) {
          super("Drop Column", 25, entity, column);
      }
  
      @Override
      public MergerToken createReverse(MergerTokenFactory factory) {
          return factory.createAddColumnToDb(getEntity(), getColumn());
      }
  
      @Override
      public void execute(MergerContext mergerContext) {
  
          // remove relationships mapped to column. duplicate List to prevent
          // ConcurrentModificationException
          List<DbRelationship> dbRelationships = new ArrayList<>(getEntity()
                  .getRelationships());
          for (DbRelationship dbRelationship : dbRelationships) {
              for (DbJoin join : dbRelationship.getJoins()) {
                  if (join.getSource() == getColumn() || join.getTarget() == getColumn()) {
                      remove(mergerContext.getDelegate(), dbRelationship, true);
                  }
              }
          }
  
          // remove ObjAttribute mapped to same column
          for (ObjEntity objEntity : getEntity().mappedObjEntities()) {
              ObjAttribute objAttribute = objEntity.getAttributeForDbAttribute(getColumn());
              if (objAttribute != null) {
                  objEntity.removeAttribute(objAttribute.getName());
                  mergerContext.getDelegate().objAttributeRemoved(objAttribute);
              }
  
          }
  
          // remove DbAttribute
          getEntity().removeAttribute(getColumn().getName());
  
          mergerContext.getDelegate().dbAttributeRemoved(getColumn());
      }
  }
  