ImmutableRelationship.java

/**
 * 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
 *
 *   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.apache.metamodel.schema;

import java.io.Serializable;

public final class ImmutableRelationship extends AbstractRelationship implements Serializable {

	private static final long serialVersionUID = 1L;

	private final Column[] primaryColumns;
	private final Column[] foreignColumns;

	public static void create(Relationship origRelationship,
			ImmutableSchema schema) {
		ImmutableTable primaryTable = getSimilarTable(
				origRelationship.getPrimaryTable(), schema);
		assert primaryTable != null;
		Column[] primaryColumns = getSimilarColumns(
				origRelationship.getPrimaryColumns(), primaryTable);
		checkSameTable(primaryColumns);

		ImmutableTable foreignTable = getSimilarTable(
				origRelationship.getForeignTable(), schema);
		assert foreignTable != null;
		Column[] foreignColumns = getSimilarColumns(
				origRelationship.getForeignColumns(), foreignTable);
		checkSameTable(foreignColumns);

		ImmutableRelationship relationship = new ImmutableRelationship(
				primaryColumns, foreignColumns);
		primaryTable.addRelationship(relationship);
		foreignTable.addRelationship(relationship);
	}

	private static Column[] getSimilarColumns(Column[] columns, Table table) {
		Column[] result = new Column[columns.length];
		for (int i = 0; i < columns.length; i++) {
			String name = columns[i].getName();
			result[i] = table.getColumnByName(name);
		}
		return result;
	}

	private static ImmutableTable getSimilarTable(Table table,
			ImmutableSchema schema) {
		String name = table.getName();
		return (ImmutableTable) schema.getTableByName(name);
	}

	private ImmutableRelationship(Column[] primaryColumns,
			Column[] foreignColumns) {
		this.primaryColumns = primaryColumns;
		this.foreignColumns = foreignColumns;
	}

	@Override
	public Column[] getPrimaryColumns() {
		return primaryColumns;
	}

	@Override
	public Column[] getForeignColumns() {
		return foreignColumns;
	}
}