org.nlab.json.stream.reader.PartialJsonStreamReaderSpliterator Maven / Gradle / Ivy

Go to download
package org.nlab.json.stream.reader;

import static org.nlab.json.stream.context.token.ObjectToken.KEY_UNINIT;

import org.nlab.exception.UncheckedExecutionException;
import org.nlab.json.stream.context.StreamContext;
import org.nlab.json.stream.context.token.ArrayToken;
import org.nlab.json.stream.context.token.ObjectToken;
import org.nlab.json.stream.context.token.Token;

import java.util.Spliterator;
import java.util.function.Consumer;

/**
 * Created by nlabrot on 08/12/15.
 */
public class PartialJsonStreamReaderSpliterator implements Spliterator {

  private final JsonMatcherStreamReader jsonMatcherReader;
  private final int depth;
  private final Token token;

  private boolean eoi = false;

  private String key;
  private int index;


  public PartialJsonStreamReaderSpliterator(JsonMatcherStreamReader jsonMatcherReader) {
    this.jsonMatcherReader = jsonMatcherReader;
    this.depth = jsonMatcherReader.getStreamContext().getElements().size();
    this.token = jsonMatcherReader.getStreamContext().getElements().peek();

    if (this.token instanceof ObjectToken) {
      key = ((ObjectToken) this.token).getKey();
    } else if (this.token instanceof ArrayToken) {
      index = ((ArrayToken) this.token).getIndex();
    }

  }

  @Override
  public boolean tryAdvance(Consumer action) {
    try {
      if (eoi) {
        return false;
      }

      if (jsonMatcherReader.isClosed()) {
        return false;
      }

      if (jsonMatcherReader.nextToken() == null) {
        return false;
      }

      action.accept(jsonMatcherReader.getStreamContext());

      if (jsonMatcherReader.getStreamContext().getElements().size() == depth) {

        if (token instanceof ObjectToken) {
          if (((ObjectToken) token).getKey().equals(key) || KEY_UNINIT.equals(key)) {
            return true;
          }
        } else if (token instanceof ArrayToken) {
          if (((ArrayToken) token).getIndex() == index) {
            return true;
          }
        }

        eoi = true;
        return false;
      } else if (jsonMatcherReader.getStreamContext().getElements().size() < depth) {
        eoi = true;
        return false;
      }


      return true;

    } catch (Exception e) {
      throw new UncheckedExecutionException(e);
    }
  }

  @Override
  public Spliterator trySplit() {
    return null;
  }

  @Override
  public long estimateSize() {
    return 0;
  }

  @Override
  public int characteristics() {
    return Spliterator.NONNULL | Spliterator.DISTINCT | Spliterator.IMMUTABLE;
  }
}