# PassiveJoinNode.java

    package org.codefilarete.stalactite.engine.runtime.load;

    import javax.annotation.Nullable;
    import java.util.IdentityHashMap;
    import java.util.Set;

    import org.codefilarete.stalactite.engine.runtime.load.EntityJoinTree.JoinType;
    import org.codefilarete.stalactite.mapping.RowTransformer.TransformerListener;
    import org.codefilarete.stalactite.query.api.Fromable;
    import org.codefilarete.stalactite.query.api.JoinLink;
    import org.codefilarete.stalactite.query.api.Selectable;
    import org.codefilarete.stalactite.sql.ddl.structure.Key;
    import org.codefilarete.stalactite.sql.result.ColumnedRow;
    import org.codefilarete.tool.Reflections;

    /**
     * Join node that does nothing particular except eventually triggering a {@link TransformerListener} (if given through
     * {@link #setConsumptionListener(EntityTreeJoinNodeConsumptionListener)})
     *
     * @author Guillaume Mary
     */
    public class PassiveJoinNode<C, T1 extends Fromable, T2 extends Fromable, I> extends AbstractJoinNode<C, T1, T2, I> {

    	PassiveJoinNode(JoinNode<?, T1> parent,
    					JoinLink<T1, I> leftJoinColumn,
    					JoinLink<T2, I> rightJoinColumn,
    					JoinType joinType,
    					Set<? extends Selectable<?>> columnsToSelect,	// of T2
    					@Nullable String tableAlias) {
    		super(parent, leftJoinColumn, rightJoinColumn, joinType, columnsToSelect, tableAlias);
    	}

    	PassiveJoinNode(JoinNode<?, T1> parent,
    					Key<T1, I> leftJoinColumn,
    					Key<T2, I> rightJoinColumn,
    					JoinType joinType,
    					Set<? extends Selectable<?>> columnsToSelect,	// of T2
    					@Nullable String tableAlias) {
    		super(parent, leftJoinColumn, rightJoinColumn, joinType, columnsToSelect, tableAlias);
    	}

    	PassiveJoinNode(JoinNode<?, T1> parent,
    					Key<T1, I> leftJoinColumn,
    					Key<T2, I> rightJoinColumn,
    					JoinType joinType,
    					Set<? extends Selectable<?>> columnsToSelect,	// of T2
    					@Nullable String tableAlias,
    					IdentityHashMap<JoinLink<?, ?>, JoinLink<?, ?>> columnClones) {
    		super(parent, leftJoinColumn, rightJoinColumn, joinType, columnsToSelect, tableAlias, columnClones);
    	}

    	@Override
    	public JoinRowConsumer toConsumer(JoinNode<C, T2> joinNode) {
    		return new PassiveJoinRowConsumer(getConsumptionListener());
    	}

    	public class PassiveJoinRowConsumer implements JoinRowConsumer {

    		/** Optional listener of ResultSet decoding */
    		@Nullable
    		private final EntityTreeJoinNodeConsumptionListener<C> consumptionListener;

    		public PassiveJoinRowConsumer(@Nullable EntityTreeJoinNodeConsumptionListener<C> consumptionListener) {
    			this.consumptionListener = consumptionListener;
    		}

    		@Override
    		public JoinNode<C, ?> getNode() {
    			return PassiveJoinNode.this;
    		}

    		void consume(EntityReference<C, ?> parentJoinEntity, ColumnedRow row) {
    			if (this.consumptionListener != null) {
    				this.consumptionListener.onNodeConsumption(parentJoinEntity.getEntity(), row);
    			}
    		}

    		/**
    		 * Implemented for debug. DO NOT RELY ON IT for anything else.
    		 */
    		@Override
    		public String toString() {
    			return Reflections.toString(this.getClass());
    		}
    	}
    }