DocumentEquality.java

package org.openprovenance.prov.model;

import java.io.PrintStream;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;

import org.apache.commons.collections.bag.HashBag;
import org.apache.log4j.Logger;

/**
 * @author Trung Dong Huynh <tdh@ecs.soton.ac.uk>
 * @author lavm
 * Comparator Class
 * 
 */


public class DocumentEquality {
    static Logger logger = Logger.getLogger(DocumentEquality.class);

    private boolean mergeDuplicates;

    final private PrintStream out;

    public DocumentEquality() {
	this.mergeDuplicates = false;
	this.out=null;
    }
    

    public DocumentEquality(boolean mergeDuplicates, PrintStream out) {
	this.mergeDuplicates = mergeDuplicates;
	this.out=out;
    }
    
    public void log(Object s) {
	if (out!=null) {
	    out.println(s);
	} else {
	    logger.debug(s);
	}
    }

    private boolean collectionEqual(Collection<?> c1, Collection<?> c2) {
	Collection<?> bag1;
	Collection<?> bag2;
	if (mergeDuplicates) {
	    bag1 = new HashSet<Object>(c1);
	    bag2 = new HashSet<Object>(c2);
	} else {
	    bag1 = new HashBag(c1);
	    bag2 = new HashBag(c2);
	}
	return bag1.equals(bag2);
    }

    @SuppressWarnings("unchecked")
    private boolean statementEqual(StatementOrBundle r1, StatementOrBundle r2) {
	// If one of the statements is a named bundle
	if (r1 instanceof Bundle && r2 instanceof Bundle) {
	    Bundle b1 = (Bundle) r1;
	    Bundle b2 = (Bundle) r2;
	    if (!b1.getId().equals(b2.getId()))
		return false;
	    List<?> stmts1 = b1.getStatement();
	    List<?> stmts2 = b2.getStatement();
	    return statementListEqual((List<StatementOrBundle>) stmts1,
				      (List<StatementOrBundle>) stmts2);
	}
	// Two normal statements
	Class<?> class1 = r1.getClass();
	if (class1 != r2.getClass()) {
	    return false;
	}
	Method[] allMethods = class1.getDeclaredMethods();
	for (Method m : allMethods) {
	    String methodName = m.getName();
	    if (methodName.startsWith("get") && (!methodName.equals("getAll"))) {
		try {
		    Object attr1 = m.invoke(r1);
		    Object attr2 = m.invoke(r2);
		    if (attr1 == null && attr2 == null)
			continue;
		    // Try the standard check first. This will also fail the
		    // test if either attributes is null.
		    if (attr1.equals(attr2))
			continue;
		    if (attr1 instanceof Collection<?>
			    && attr1 instanceof Collection<?>)
			if (collectionEqual((Collection<?>) attr1,
					    (Collection<?>) attr2))
			    continue;
		    /*
		     * // the two attributes are not equal String attrName =
		     * methodName.substring(3);
		     * System.out.println("The following " + attrName +
		     * " attributes are not the same");
		     * System.out.println(attr1); System.out.println(attr2);
		     * 
		     * logger.debug("The following " + attrName +
		     * " attributes are not the same"); logger.debug(attr1);
		     * logger.debug(attr2);
		     */
		    return false;
		} catch (Exception e) {
		    // Any exception means no equality
		    log(e);
		    return false;
		}
	    }
	}

	return true;
    }

    private boolean statementListEqual(List<StatementOrBundle> stmts1,
				       List<StatementOrBundle> stmts2) {
	if (stmts1.size() != stmts2.size()) {
	    return false;
	}
	// Cloning the lists to avoid modification of the originals
	List<StatementOrBundle> list1 = new ArrayList<StatementOrBundle>(stmts1);
	List<StatementOrBundle> list2 = new ArrayList<StatementOrBundle>(stmts2);
	for (StatementOrBundle stmt1 : list1) {
	    // Try to find the same in list2
	    StatementOrBundle found = null;
	    for (StatementOrBundle stmt2 : list2) {
		if (statementEqual(stmt1, stmt2)) {
		    found = stmt2;
		    break;
		}
	    }
	    if (found == null) {
		log("---------------------------");
		log("Cannot find the following statement in the second document");
		log("---------------------------");
		log("statement: " + stmt1);
		log("---------------------------");
		log("list of statements: ");
		log(stmts2);
		log("---------------------------");

		return false;
	    }
	    list2.remove(found);
	}

	return true;
    }

    public boolean check(Document d1, Document d2) {
	return statementListEqual(d1.getStatementOrBundle(),
				  d2.getStatementOrBundle());
    }

}