/*
* Ivory: A Hadoop toolkit for web-scale information retrieval
*
* 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 ivory.smrf.model.builder;
import ivory.core.ConfigurationException;
import org.w3c.dom.Node;
import com.google.common.base.Preconditions;
/**
* @author Don Metzler
*/
public abstract class ExpressionGenerator {
public abstract void configure(Node domNode) throws ConfigurationException;
public abstract Expression getExpression(String[] terms);
@SuppressWarnings("unchecked")
public static ExpressionGenerator create(String type, Node domNode) throws ConfigurationException {
Preconditions.checkNotNull(type);
Preconditions.checkNotNull(domNode);
try {
Class<? extends ExpressionGenerator> clz =
(Class<? extends ExpressionGenerator>) Class.forName(type);
ExpressionGenerator f = clz.newInstance();
f.configure(domNode);
return f;
} catch (Exception e) {
throw new ConfigurationException(
"Unable to instantiate ExpressionGenerator \"" + type + "\"!", e);
}
}
}