LinkRelationBlackList.java

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 * Copyright (C) 2018 wcm.io
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 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
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package io.wcm.caravan.hal.comparison.impl.links.steps;

import java.util.Collections;
import java.util.List;

import io.wcm.caravan.hal.comparison.HalComparisonContext;
import io.wcm.caravan.hal.comparison.HalComparisonStrategy;
import io.wcm.caravan.hal.comparison.HalDifference;
import io.wcm.caravan.hal.comparison.impl.context.HalComparisonContextImpl;
import io.wcm.caravan.hal.comparison.impl.links.LinkProcessingStep;
import io.wcm.caravan.hal.resource.Link;


/**
 * Ignore specific linked resources as configured in
 * {@link HalComparisonStrategy#ignoreLinkTo(HalComparisonContext)}
 */
public class LinkRelationBlackList implements LinkProcessingStep {

  private final HalComparisonStrategy strategy;

  /**
   * @param strategy that defines which relations should be ignored
   */
  public LinkRelationBlackList(HalComparisonStrategy strategy) {
    this.strategy = strategy;
  }

  @Override
  public List<HalDifference> apply(HalComparisonContextImpl context, List<Link> expected, List<Link> actual) {

    boolean blackListed = strategy.ignoreLinkTo(context);
    if (blackListed) {
      expected.clear();
      actual.clear();
    }

    return Collections.emptyList();
  }

}