BuildResource.java

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 * wcm.io
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 * Copyright (C) 2014 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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 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
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package io.wcm.caravan.pipeline.extensions.hal.action;

import org.osgi.annotation.versioning.ConsumerType;

import io.wcm.caravan.hal.resource.HalResource;
import io.wcm.caravan.hal.resource.util.HalBuilder;
import io.wcm.caravan.pipeline.JsonPipelineAction;
import io.wcm.caravan.pipeline.JsonPipelineContext;
import io.wcm.caravan.pipeline.JsonPipelineOutput;
import io.wcm.caravan.pipeline.JsonPipelineOutputException;
import rx.Observable;

/**
 * A pipeline action you can use if you want to build a new {@link HalResource} based on another {@link HalResource}
 * from the previous step's output.
 * @deprecated use {@link CreateResource} instead
 */
@Deprecated
//CHECKSTYLE:OFF
@ConsumerType
public abstract class BuildResource implements JsonPipelineAction {
  //CHECKSTYLE:ON

  private final String selfHref;

  /**
   * @param selfHref the path and query parameters to use in the output's self link
   */
  public BuildResource(String selfHref) {
    this.selfHref = selfHref;
  }

  @Override
  public String getId() {
    return "BUILD-RESOURCE(" + selfHref + ")";
  }

  @Override
  public final Observable<JsonPipelineOutput> execute(JsonPipelineOutput previousStepOutput, JsonPipelineContext pipelineContext) {

    if (!previousStepOutput.getPayload().isObject()) {
      throw new JsonPipelineOutputException(BuildResource.class.getName()
          + " expects the output of the previous step to be a JSON *object* output, but got "
          + previousStepOutput.getPayload().toString());
    }

    HalResource input = new HalResource((previousStepOutput.getPayload()));

    HalBuilder outputBuilder = new HalBuilder(selfHref);

    HalResource output = build(input, outputBuilder);

    return Observable.just(previousStepOutput.withPayload(output.getModel()));
  }

  /**
   * @param input the original {@link HalResource} from the previous step's output
   * @param outputBuilder a builder that already contains a self-link, but no state
   * @return the new HalResource that will be returned as the result of the pipeline action
   */
  public abstract HalResource build(HalResource input, HalBuilder outputBuilder);

}