package org.apache.torque.templates.transformer.om;
/*
* 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.
*/
import java.util.ArrayList;
import java.util.List;
import org.apache.torque.generator.source.SourceElement;
import org.apache.torque.templates.TorqueSchemaAttributeName;
import org.apache.torque.templates.TorqueSchemaElementName;
/**
* Utility class containing methods to find certain elements
* in the source tree.
*
* $Id: FindHelper.java 1331196 2012-04-27 02:56:12Z tfischer $
*/
final class FindHelper
{
/**
* Private constructor for utility class.
*/
private FindHelper()
{
}
/**
* Finds a table in the given root element by name. The root element must
* be a database element.
*
* @param root the database Source element, not null.
* @param tableName the table name, not null.
* @param searchExternalSchemata if the table should also be located
* in the external schemata.
*
* @return the column's source element, or null if no matching table
* exists.
*/
public static SourceElement findTable(
SourceElement root,
String tableName,
boolean searchExternalSchemata)
{
if (!TorqueSchemaElementName.DATABASE.getName().equals(
root.getName()))
{
throw new IllegalArgumentException("Wrong source element "
+ root.getName());
}
for (SourceElement table : root.getChildren(
TorqueSchemaElementName.TABLE))
{
if (tableName.equals(table.getAttribute(
TorqueSchemaAttributeName.NAME)))
{
return table;
}
}
if (searchExternalSchemata)
{
for (SourceElement externalSchema : root.getChildren(
TorqueSchemaElementName.EXTERNAL_SCHEMA))
{
SourceElement databaseElement
= externalSchema.getChild(TorqueSchemaElementName.DATABASE);
SourceElement result = findTable(
databaseElement,
tableName,
searchExternalSchemata);
if (result != null)
{
return result;
}
}
}
return null;
}
/**
* Finds a column in a table by name.
*
* @param table the table Source element, not null.
* @param columnName the column name, not null.
*
* @return the column's source element, or null if no matching column
* exists.
*/
public static SourceElement findColumn(
SourceElement table,
String columnName)
{
if (!TorqueSchemaElementName.TABLE.getName().equals(
table.getName()))
{
throw new IllegalArgumentException("Wrong source element "
+ table.getName());
}
for (SourceElement column : table.getChildren(
TorqueSchemaElementName.COLUMN))
{
if (column.getAttribute(TorqueSchemaAttributeName.NAME)
.equals(columnName))
{
return column;
}
}
return null;
}
/**
* Finds all foreign key in one table that reference a certain other table.
*
* @param table the table containing the foreign keys to search, not null.
* @param tableName the name of the foreign table in the foreign Key.
*
* @return the foreign keys referencing the given table name.
*/
public static List<SourceElement> findForeignKeyByReferencedTable(
SourceElement table,
String tableName)
{
List<SourceElement> result = new ArrayList<SourceElement>();
if (!TorqueSchemaElementName.TABLE.getName().equals(
table.getName()))
{
throw new IllegalArgumentException("Wrong source element "
+ table.getName());
}
for (SourceElement foreignKey : table.getChildren(
TorqueSchemaElementName.FOREIGN_KEY))
{
if (foreignKey.getAttribute(
TorqueSchemaAttributeName.FOREIGN_TABLE)
.equals(tableName))
{
result.add(foreignKey);
}
}
return result;
}
}