ProjectionOp.java

package org.olap4j.driver.olap4ld.linkeddata;

import java.util.List;
import java.util.Map;

import org.olap4j.driver.olap4ld.helper.Olap4ldLinkedDataUtil;
import org.semanticweb.yars.nx.Node;

/**
 * This operator defines the projected measures. Not mentioned measures in input are removed from
 * the cube.
 * 
 * @author benedikt
 * 
 */
public class ProjectionOp implements LogicalOlapOp {

	public List<Node[]> projectedMeasures;
	public LogicalOlapOp inputOp;

	/**
	 * 
	 * @param inputOp
	 * @param projections A list of projected measures using the metadata schema.
	 */
	public ProjectionOp(LogicalOlapOp inputOp, List<Node[]> projections) {
		this.inputOp = inputOp;
		this.projectedMeasures = projections;
	}

	public String toString() {
		if (projectedMeasures != null && !projectedMeasures.isEmpty()) {

			Map<String, Integer> map = Olap4ldLinkedDataUtil
					.getNodeResultFields(projectedMeasures.get(0));

			String measuresStringArray[] = new String[projectedMeasures.size() - 1];
			// First is the header!
			for (int i = 1; i < projectedMeasures.size(); i++) {
				measuresStringArray[i - 1] = projectedMeasures.get(i)[map
						.get("?MEASURE_UNIQUE_NAME")].toString();
			}

			return "Projection ("
					+ inputOp.toString()
					+ ", {"
					+ Olap4ldLinkedDataUtil.implodeArray(measuresStringArray,
							", ") + "})";
		}
		return "Projection (" + inputOp.toString() + ", {})";
	}

	@Override
	public void accept(LogicalOlapOperatorQueryPlanVisitor v)
			throws QueryException {
		v.visit(this);
		// visit the projection input op
		inputOp.accept(v);
	}

}