package org.simantics.interop.issues;

import org.simantics.db.ReadGraph;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.request.Read;

/**
 * AndRead can be used to combine multiple requests into single one. If all reads return true or null, this returns true.
 * @author Marko Luukkainen <marko.luukkainen@vtt.fi>
 *
 */
public class AndRead implements Read<Boolean>{

	private Read<Boolean> reads[];
	
	public AndRead(Read<Boolean>... reads) {
		this.reads = reads;
	}
	
	@Override
	public Boolean perform(ReadGraph graph) throws DatabaseException {
		Boolean b = null;
		for (Read<Boolean> r : reads) {
			b = r.perform(graph);
			if(b != null && !b)
				return false;
		}
		return true;
	}
}