/*
Copyright (c) 2015, Emir Pasic
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this
  list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

// Stateful iterator pattern for ordered containers.

package containers

// Stateful iterator for ordered containers whose values can be fetched by an index.
type IteratorWithIndex interface {
	// Moves the iterator to the next element and returns true if there was a next element in the container.
	// If Next() returns true, then next element's index and value can be retrieved by Index() and Value().
	// Modifies the state of the iterator.
	Next() bool
	// Returns the current element's value.
	// Does not modify the state of the iterator.
	Value() interface{}
	// Returns the current element's index.
	// Does not modify the state of the iterator.
	Index() int
}

// Stateful iterator for ordered containers whose elements are key value pairs.
type IteratorWithKey interface {
	// Moves the iterator to the next element and returns true if there was a next element in the container.
	// If Next() returns true, then next element's key and value can be retrieved by Key() and Value().
	// Modifies the state of the iterator.
	Next() bool
	// Returns the current element's value.
	// Does not modify the state of the iterator.
	Value() interface{}
	// Returns the current element's key.
	// Does not modify the state of the iterator.
	Key() interface{}
}