akka.japi.pf.AbstractPFBuilder Maven / Gradle / Ivy

/*
 * Copyright (C) 2009-2020 Lightbend Inc. 
 */

package akka.japi.pf;

import scala.PartialFunction;

/**
 * A builder for {@link scala.PartialFunction}.
 *
 * @param  the input type, that this PartialFunction will be applied to
 * @param  the return type, that the results of the application will have
 */
abstract class AbstractPFBuilder {

  protected PartialFunction statements = null;

  protected void addStatement(PartialFunction statement) {
    if (statements == null) statements = statement;
    else statements = statements.orElse(statement);
  }

  /**
   * Build a {@link scala.PartialFunction} from this builder. After this call the builder will be
   * reset.
   *
   * @return a PartialFunction for this builder.
   */
  public PartialFunction build() {
    PartialFunction empty = CaseStatement.empty();
    PartialFunction statements = this.statements;

    this.statements = null;
    if (statements == null) return empty;
    else return statements.orElse(empty);
  }
}