net.anwiba.commons.lang.functional.IIterable Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of anwiba-commons-lang Show documentation

anwiba commons lang project

There is a newer version: 1.2.50

/*
 * #%L
 * anwiba commons core
 * %%
 * Copyright (C) 2007 - 2016 Andreas Bartels
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 2.1 of the
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Lesser Public License for more details.
 * 
 * You should have received a copy of the GNU General Lesser Public
 * License along with this program.  If not, see
 * .
 * #L%
 */

package net.anwiba.commons.lang.functional;

import java.util.NoSuchElementException;

public interface IIterable {

  IIterator iterator();

  default IIterable iterable(final IAcceptor acceptor) {

    return new IIterable() {

      @Override
      public IIterator iterator() {
        return iterator(acceptor);
      }
    };
  }

  default IIterator iterator(final IAcceptor acceptor) {
    return new IIterator() {

      private final IIterator iterator = iterator();
      private O item = null;

      @Override
      public boolean hasNext() throws E {
        while (this.iterator.hasNext()) {
          final O i = this.iterator.next();
          if (acceptor.accept(i) && (this.item = i) != null) {
            return true;
          }
        }
        return false;
      }

      @Override
      public O next() throws E {
        try {
          if (this.item != null || hasNext()) {
            return this.item;
          }
          throw new NoSuchElementException();
        } finally {
          this.item = null;
        }
      }
    };
  }

  default O first(final IAcceptor acceptor) throws E {
    final IIterator iterator = this.iterator();
    while (iterator.hasNext()) {
      final O value = iterator.next();
      if (acceptor.accept(value)) {
        return value;
      }
    }
    return null;
  }

  default void foreach(final IConsumer consumer) throws E {
    final IIterator iterator = this.iterator();
    while (iterator.hasNext()) {
      final O value = iterator.next();
      consumer.consume(value);
    }
  }

  default  R aggregate(final R identity, final IAggregator adder) throws E {
    final IIterator iterator = this.iterator();
    R result = identity;
    while (iterator.hasNext()) {
      result = adder.aggregate(result, iterator.next());
    }
    return result;
  }

}