package com.tinkerpop.blueprints;
import org.apache.commons.configuration.Configuration;
import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.MapConfiguration;
import org.apache.commons.configuration.PropertiesConfiguration;
import java.io.File;
import java.util.Map;
/**
* Factory to construct new Graph instances from a Configuration object or properties file.
*
* @author Stephen Mallette (http://stephen.genoprime.com)
*/
public class GraphFactory {
/**
* Open a graph. See each Graph instance for its configuration options.
*
* @param configuration A configuration object that specifies the minimally required properties for a Graph instance.
* This minimum is determined by the Graph instance itself.
* @return A Graph instance.
*/
public static Graph open(final Configuration configuration) {
final String clazz = configuration.getString("blueprints.graph", null);
if (clazz == null) {
throw new RuntimeException("Configuration must contain a valid 'blueprints.graph' setting");
}
Class graphClass;
try {
graphClass = Class.forName(clazz);
} catch (ClassNotFoundException cnfe) {
throw new RuntimeException(String.format("GraphFactory could not find [%s]. Ensure that the jar is in the classpath.", clazz));
}
Graph g;
try {
// directly instantiate if it is a Graph class otherwise try to use a factory
if (Graph.class.isAssignableFrom(graphClass)) {
g = (Graph) graphClass.getConstructor(Configuration.class).newInstance(configuration);
} else {
g = (Graph) graphClass.getMethod("open", Configuration.class).invoke(null, configuration);
}
} catch (NoSuchMethodException nsme) {
throw new RuntimeException(String.format("GraphFactory can only instantiate Graph implementations that have a constructor with a single Apache Commons Configuration argument. [%s] does not seem to have one.", clazz));
} catch (Exception ex) {
throw new RuntimeException(String.format("GraphFactory could not instantiate this Graph implementation [%s].", clazz), ex);
}
return g;
}
/**
* Open a graph. See each Graph instance for its configuration options.
*
* @param configurationFile The location of a configuration file that specifies the minimally required properties
* for a Graph instance. This minimum is determined by the Graph instance itself.
* @return A Graph instance.
*/
public static Graph open(final String configurationFile) {
return open(getConfiguration(new File(configurationFile)));
}
/**
* Open a graph. See each Graph instance for its configuration options.
*
* @param configuration A Map based configuration that will be converted to an Apache configuration object
* via MapConfiguration and passed to the appropriate overload.
*
* @return A Graph instance.
*/
public static Graph open(final Map configuration) {
return open(new MapConfiguration(configuration));
}
private static final Configuration getConfiguration(final File dirOrFile) {
if (dirOrFile == null) {
throw new IllegalArgumentException("Need to specify a configuration file or storage directory");
}
if (!dirOrFile.isFile()) {
throw new IllegalArgumentException("Location of configuration must be a file");
}
try {
return new PropertiesConfiguration(dirOrFile);
} catch (ConfigurationException e) {
throw new IllegalArgumentException("Could not load configuration at: " + dirOrFile, e);
}
}
}