IteratorThunk.java

/***************************************************************************
   Copyright 2014 Emily Estes

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
***************************************************************************/
package net.metanotion.functor;


import java.util.Iterator;

/** Turn an iterator into a thunk which produces a stream of values for each call.
	@param <E> The type of values provided by the iterator and produced by the thunk.
*/
public final class IteratorThunk<E> implements Thunk<E> {
	private final Iterator<E> it;
	/** Produce a thunk which iterates a list.
		@param list The list we're using as the output of the thunk.
	*/
	public IteratorThunk(final Iterable<E> list) { this.it = list.iterator(); }
	/** Produce a thunk which returns the results of an iterator.
		@param it The iterator that produces the output.
	*/
	public IteratorThunk(final Iterator<E> it) { this.it = it; }

	@Override public E eval() throws Exception { return it.next(); }
}