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Nadel is a Java library that combines multiple GrahpQL services together into one API.

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package graphql.nadel.engine.execution;

import graphql.Internal;
import graphql.execution.ResultPath;

import java.util.ArrayList;
import java.util.List;

@Internal
public class PathMapper {
    /**
     * This function corrects the given {@code executionPath} by taking the parent path
     * and appending the last child segment to it. It also replaces the last String path
     * segment with {@code resultKey}.
     * 
     * There are two reasons for using the parent path:
     * 
 

     * Firstly, to fix hydration paths i.e. the {@code executionPath} will be the hydrated
     * field path and the parent path will be where the hydrated object is stitched in and
     * we need to merge those two paths.
     * 

     * e.g. if we hydrate {@code reporter} here
     * 
{@code
     * type Issue {
     *     reporter: User => hydrated from Users.user(id: $source.reporterId)
     * }
     * }
     * Then the {@code executionPath} could be {@code /user/name} and the parent path would
     * be {@code /issue/reporter} and the desired path would be {@code /issue/reporter/name}
     * 

     * Secondly, to fix renamed paths e.g. given the parent path {@code /devOpsRelationships}
     * and given the {@code executionPath} {@code /relationships/nodes}
     * 

     * where the field {@code relationships} was renamed to {@code devOpsRelationships}
     * 

     * we should take the renamed parent path {@code /devopsRelationships}
     * 

     * and append the child path {@code nodes} to it
     *
     * @param executionPath the path to correct
     * @param resultKey     the correct segment name to use
     * @param environment   context for the current path
     * @return the fixed path as described above
     */
    public ResultPath mapPath(ResultPath executionPath, String resultKey, UnapplyEnvironment environment) {
        List