JavaExternalJoins.java

External join (advanded).This example shows a complex use of external join. Its source code is under the samples/java directory.

import cogitant.base.Environment;
import cogitant.base.IOHandler;
import cogitant.base.EnvironmentObject;
import cogitant.base.Graph;
import cogitant.base.GraphObject;
import cogitant.base.GraphSubset;
import java.io.FileInputStream;
import java.util.Collection;
import java.util.Vector;

public class JavaExternalJoins
{
    public static void run(String prefix) throws Exception
    {
        // Load support and graphs
        Environment environment = new cogitant.jni.Environment();
        environment.setIOConfig(IOHandler.ConfigPropertyBool.KEEPGRAPHOBJECTIDENTIFIERS, true);
        environment.loadSupport(new FileInputStream(prefix + "/bcgct/bucolic/bucolic.bcs"), IOHandler.Format.BCGCT);
        Collection<EnvironmentObject> loadedgraphs = environment.loadObjects(new FileInputStream(prefix + "/bcgct/bucolic/sleepandfish.bcg"), IOHandler.Format.BCGCT);
        Graph g1 = loadedgraphs.iterator().next().asGraph();
        loadedgraphs = environment.loadObjects(new FileInputStream(prefix + "/bcgct/bucolic/simplequery.bcg"), IOHandler.Format.BCGCT);
        Graph g2 = loadedgraphs.iterator().next().asGraph();
        // External joins
        Vector<GraphObject> ng1 = new Vector<GraphObject>();
        Vector<GraphObject> ng2 = new Vector<GraphObject>();
        ng1.add(g1.findByIdentifier("c14")); ng2.add(g2.findByIdentifier("c1")); // c14(g1) with c1(g2)
        ng1.add(g1.findByIdentifier("c15")); ng2.add(g2.findByIdentifier("c2")); // c15(g1) with c2(g2)
        GraphSubset subsetg2 = g2.newSubset();
        subsetg2.select(g2.findByIdentifier("c1"));
        subsetg2.select(g2.findByIdentifier("c2"));
        subsetg2.select(g2.findByIdentifier("c3"));
        subsetg2.select(g2.findByIdentifier("r2"));// note that r1 is not copied
        environment.graphExternalJoin(g1, g2, subsetg2, ng1, ng2);
        // Print result
        Vector<EnvironmentObject> vout = new Vector<EnvironmentObject>();
        vout.add(g1);
        System.out.println(environment.saveObjectsString(vout, IOHandler.Format.LINEARFORM));
    }
    
    public static void main(String args[]) throws Exception
    {
        String prefix = "..";
        if (args.length == 1)
            prefix = args[0];
        System.out.println("prefix: " + prefix);
        run(prefix);
    }
}