Class BaseOperatorPlan

src/org/apache/pig/newplan/BaseOperatorPlan.java:36–530

import org.apache.pig.impl.util.Pair;

public abstract class BaseOperatorPlan implements OperatorPlan {

    protected List<Operator> ops;
    protected PlanEdge fromEdges;
    protected PlanEdge toEdges;
    protected PlanEdge softFromEdges;
    protected PlanEdge softToEdges;

    private List<Operator> roots;
    private List<Operator> leaves;
    protected static final Log log =
        LogFactory.getLog(BaseOperatorPlan.class);
 
    public BaseOperatorPlan() {
        ops = new ArrayList<Operator>();
        roots = new ArrayList<Operator>();
        leaves = new ArrayList<Operator>();
        fromEdges = new PlanEdge();
        toEdges = new PlanEdge();
        softFromEdges = new PlanEdge();
        softToEdges = new PlanEdge();
    }
    
    @SuppressWarnings("unchecked")
    public BaseOperatorPlan(BaseOperatorPlan other) {
        // (shallow) copy constructor
        ops = (List<Operator>) ((ArrayList<Operator>) other.ops).clone();
        roots = (List<Operator>) ((ArrayList) other.roots).clone();
        leaves = (List<Operator>) ((ArrayList) other.leaves).clone();
        fromEdges = other.fromEdges.shallowClone();
        toEdges = other.toEdges.shallowClone();
        softFromEdges = other.softFromEdges.shallowClone();
        softToEdges = other.softToEdges.shallowClone();
    }
    
    /**
     * Get number of nodes in the plan.
     */
    public int size() {
        return ops.size();
    }

    /**
     * Get all operators in the plan that have no predecessors.
     * @return all operators in the plan that have no predecessors, or
     * an empty list if the plan is empty.
     */
    public List<Operator> getSources() {
        if (roots.size() == 0 && ops.size() > 0) {
            for (Operator op : ops) {               
                if (toEdges.get(op) == null) {
                    roots.add(op);
                }
            }
        }
        return roots;
    }