org.fisco.bcos.web3j.utils.Flowables Maven / Gradle / Ivy

Go to download
package org.fisco.bcos.web3j.utils;

import io.reactivex.BackpressureStrategy;
import io.reactivex.Flowable;
import java.math.BigInteger;

/** Flowable utility functions. */
public class Flowables {

  public static Flowable range(final BigInteger startValue, final BigInteger endValue) {
    return range(startValue, endValue, true);
  }

  /**
   * Simple {@link Flowable} implementation to emit a range of BigInteger values.
   *
   * @param startValue first value to emit in range
   * @param endValue final value to emit in range
   * @param ascending direction to iterate through range
   * @return a {@link Flowable} instance to emit this range of values
   */
  public static Flowable range(
      final BigInteger startValue, final BigInteger endValue, final boolean ascending) {
    if (startValue.compareTo(BigInteger.ZERO) < 0) {
      throw new IllegalArgumentException("Negative start index cannot be used");
    } else if (startValue.compareTo(endValue) > 0) {
      throw new IllegalArgumentException("Negative start index cannot be greater then end index");
    }

    if (ascending) {
      return Flowable.create(
          subscriber -> {
            for (BigInteger i = startValue;
                i.compareTo(endValue) < 1 && !subscriber.isCancelled();
                i = i.add(BigInteger.ONE)) {
              subscriber.onNext(i);
            }

            if (!subscriber.isCancelled()) {
              subscriber.onComplete();
            }
          },
          BackpressureStrategy.BUFFER);
    } else {
      return Flowable.create(
          subscriber -> {
            for (BigInteger i = endValue;
                i.compareTo(startValue) > -1 && !subscriber.isCancelled();
                i = i.subtract(BigInteger.ONE)) {
              subscriber.onNext(i);
            }

            if (!subscriber.isCancelled()) {
              subscriber.onComplete();
            }
          },
          BackpressureStrategy.BUFFER);
    }
  }
}