/*
* LensKit, an open source recommender systems toolkit.
* Copyright 2010-2014 LensKit Contributors. See CONTRIBUTORS.md.
* Work on LensKit has been funded by the National Science Foundation under
* grants IIS 05-34939, 08-08692, 08-12148, and 10-17697.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package org.grouplens.lenskit.config;
import com.google.common.base.Preconditions;
import groovy.lang.Closure;
import groovy.lang.GroovyRuntimeException;
import org.grouplens.lenskit.core.LenskitConfiguration;
import org.grouplens.lenskit.core.RecommenderConfigurationException;
import javax.annotation.Nonnull;
import java.io.File;
import java.io.IOException;
import java.net.URL;
/**
* LensKit configuration helper utilities.
*
* @since 1.2
* @author <a href="http://www.grouplens.org">GroupLens Research</a>
*/
public class ConfigHelpers {
/**
* Load a LensKit configuration from a Groovy closure. This is useful for using the Groovy
* DSL in unit tests.
*
* @param block The block to evaluate. This block will be evaluated with a delegate providing
* the LensKit DSL and the {@link groovy.lang.Closure#DELEGATE_FIRST} resolution strategy.
* @return The LensKit configuration.
* @see ConfigurationLoader#load(groovy.lang.Closure)
*/
public static LenskitConfiguration load(Closure<?> block) throws RecommenderConfigurationException {
Preconditions.checkNotNull(block, "Configuration block");
LenskitConfiguration config = new LenskitConfiguration();
configure(config, block);
return config;
}
/**
* Load a LensKit configuration from a script (as a string).
*
* @param script The script source text to evaluate.
* @return The LensKit configuration.
* @deprecated Loading from Groovy source strings is confusing.
*/
@Deprecated
public static LenskitConfiguration load(String script) throws RecommenderConfigurationException {
return new ConfigurationLoader().load(script);
}
/**
* Load a LensKit configuration from a script file.
*
* @param script The script source file to evaluate.
* @return The LensKit configuration.
*/
public static LenskitConfiguration load(File script) throws IOException, RecommenderConfigurationException {
return new ConfigurationLoader().load(script);
}
/**
* Load a LensKit configuration from a script URL.
*
* @param script The script source URL to evaluate.
* @return The LensKit configuration.
*/
public static LenskitConfiguration load(URL script) throws IOException, RecommenderConfigurationException {
return new ConfigurationLoader().load(script);
}
/**
* Modify a configuration from a closure. The class loader is not really consulted in this case.
* @param block The block to evaluate. This block will be evaluated with a delegate providing
* the LensKit DSL and the {@link Closure#DELEGATE_FIRST} resolution strategy.
*/
public static void configure(LenskitConfiguration config, @Nonnull Closure<?> block) throws RecommenderConfigurationException {
Preconditions.checkNotNull(block, "Configuration block");
BindingDSL delegate = LenskitConfigDSL.forConfig(config);
try {
GroovyUtils.callWithDelegate(block, delegate);
} catch (GroovyRuntimeException e) {
// this quite possibly wraps an exception we want to throw
if (e.getClass().equals(GroovyRuntimeException.class) && e.getCause() != null) {
throw new RecommenderConfigurationException("Error evaluating Groovy block",
e.getCause());
} else {
throw new RecommenderConfigurationException("Error evaluating Groovy block", e);
}
} catch (RuntimeException e) {
throw new RecommenderConfigurationException("Error evaluating Groovy block", e);
}
}
}