DocumentEquality.java

/**
 * 
 */
package org.openprovenance.prov.sql;

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;
import org.openprovenance.prov.model.StatementOrBundle;
import org.openprovenance.prov.model.Document;

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

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

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

	public DocumentEquality(boolean mergeDuplicates) {
		this.mergeDuplicates = mergeDuplicates;
	}

	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 statemens is a named bundle
		if (r1 instanceof Bundle || r2 instanceof 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);
					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
					logger.debug(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) {
				logger.debug("Cannot find the following statement in the second document");
				logger.debug(stmt1);
				return false;
			}
			list2.remove(found);
		}

		return true;
	}

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

}