/***********************************************************************************************************************
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* 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.
**********************************************************************************************************************/
package eu.stratosphere.compiler.postpass;
import eu.stratosphere.compiler.CompilerException;
import eu.stratosphere.types.Key;
public class PostPassUtils {
public static <X> Class<? extends Key<?>>[] getKeys(AbstractSchema<Class< ? extends X>> schema, int[] fields) throws MissingFieldTypeInfoException {
@SuppressWarnings("unchecked")
Class<? extends Key<?>>[] keyTypes = new Class[fields.length];
for (int i = 0; i < fields.length; i++) {
Class<? extends X> type = schema.getType(fields[i]);
if (type == null) {
throw new MissingFieldTypeInfoException(i);
} else if (Key.class.isAssignableFrom(type)) {
@SuppressWarnings("unchecked")
Class<? extends Key<?>> keyType = (Class<? extends Key<?>>) type;
keyTypes[i] = keyType;
} else {
throw new CompilerException("The field type " + type.getName() +
" cannot be used as a key because it does not implement the interface 'Key'");
}
}
return keyTypes;
}
}