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package org.graalvm.compiler.phases.graph;

import java.util.List;

import org.graalvm.compiler.nodes.AbstractBeginNode;
import org.graalvm.compiler.nodes.AbstractMergeNode;
import org.graalvm.compiler.nodes.ControlSplitNode;
import org.graalvm.compiler.nodes.LoopBeginNode;
import org.graalvm.compiler.nodes.LoopEndNode;

public abstract class MergeableState<T> {

    @Override
    public abstract T clone();

    
This method is called on merge on the state of the first branch. The withStates list contains the states of the of the other branches in the order of the merge's end nodes. 
Params:
merge – the merge node
withStates – the state at the merge's end node except the first one./**
     * This method is called on merge on the state of the first branch. The {@code withStates} list
     * contains the states of the of the other branches in the order of the merge's end nodes.
     *
     * @param merge the merge node
     * @param withStates the state at the merge's end node except the first one.
     */
    public abstract boolean merge(AbstractMergeNode merge, List<T> withStates);

    
This method is called before a loop is entered (before the LoopBeginNode is visited). 
Params:
loopBegin – the begin node of the loop/**
     * This method is called before a loop is entered (before the {@link LoopBeginNode} is visited).
     *
     * @param loopBegin the begin node of the loop
     */
    public void loopBegin(LoopBeginNode loopBegin) {
        // empty default implementation
    }

    
This method is called after all LoopEndNodes belonging to a loop have been visited. 
Params:
loopBegin – the begin node of the loop
loopEndStates – the states at the loop ends, sorted according to LoopBeginNode.orderedLoopEnds()/**
     * This method is called after all {@link LoopEndNode}s belonging to a loop have been visited.
     *
     * @param loopBegin the begin node of the loop
     * @param loopEndStates the states at the loop ends, sorted according to
     *            {@link LoopBeginNode#orderedLoopEnds()}
     */
    public void loopEnds(LoopBeginNode loopBegin, List<T> loopEndStates) {
        // empty default implementation
    }

    
This method is called before the successors of a ControlSplitNode are visited. 
Params:
node – the successor of the control split that is about to be visited/**
     * This method is called before the successors of a {@link ControlSplitNode} are visited.
     *
     * @param node the successor of the control split that is about to be visited
     */
    public void afterSplit(AbstractBeginNode node) {
        // empty default implementation
    }
}