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Merge pull request #779 from mitchellirvin/bst-iterator

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#778: Binary Search Tree Iterator
This commit is contained in:
Narendra Pathai 2018-08-30 12:46:13 +05:30 committed by GitHub
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iterator/etc/iterator.ucls
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<?xml version="1.0" encoding="UTF-8"?>
<class-diagram version="1.1.8" icons="true" automaticImage="PNG" always-add-relationships="false" generalizations="true"
realizations="true" associations="true" dependencies="false" nesting-relationships="true">
<class id="1" language="java" name="com.iluwatar.iterator.TreasureChest" project="iterator"
<class id="1" language="java" name="com.iluwatar.iterator.list.TreasureChest" project="iterator"
file="/iterator/src/main/java/com/iluwatar/iterator/TreasureChest.java" binary="false" corner="BOTTOM_RIGHT">
<position height="124" width="195" x="1" y="237"/>
<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
@ -10,7 +10,7 @@
<operations public="true" package="true" protected="true" private="true" static="true"/>
</display>
</class>
<class id="2" language="java" name="com.iluwatar.iterator.Item" project="iterator"
<class id="2" language="java" name="com.iluwatar.iterator.list.Item" project="iterator"
file="/iterator/src/main/java/com/iluwatar/iterator/Item.java" binary="false" corner="BOTTOM_RIGHT">
<position height="160" width="157" x="195" y="401"/>
<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
@ -19,7 +19,7 @@
<operations public="true" package="true" protected="true" private="true" static="true"/>
</display>
</class>
<enumeration id="3" language="java" name="com.iluwatar.iterator.ItemType" project="iterator"
<enumeration id="3" language="java" name="com.iluwatar.iterator.list.ItemType" project="iterator"
file="/iterator/src/main/java/com/iluwatar/iterator/ItemType.java" binary="false" corner="BOTTOM_RIGHT">
<position height="160" width="145" x="388" y="601"/>
<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
@ -28,7 +28,7 @@
<operations public="true" package="true" protected="true" private="true" static="true"/>
</display>
</enumeration>
<interface id="4" language="java" name="com.iluwatar.iterator.ItemIterator" project="iterator"
<interface id="4" language="java" name="com.iluwatar.iterator.list.ItemIterator" project="iterator"
file="/iterator/src/main/java/com/iluwatar/iterator/ItemIterator.java" binary="false" corner="BOTTOM_RIGHT">
<position height="106" width="131" x="236" y="237"/>
<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
@ -37,7 +37,7 @@
<operations public="true" package="true" protected="true" private="true" static="true"/>
</display>
</interface>
<class id="5" language="java" name="com.iluwatar.iterator.TreasureChestItemIterator" project="iterator"
<class id="5" language="java" name="com.iluwatar.iterator.list.TreasureChestItemIterator" project="iterator"
file="/iterator/src/main/java/com/iluwatar/iterator/TreasureChestItemIterator.java" binary="false"
corner="BOTTOM_RIGHT">
<position height="160" width="323" x="236" y="37"/>

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iterator/src/main/java/com/iluwatar/iterator/App.java
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/**
* The MIT License
* Copyright (c) 2014-2016 Ilkka Seppälä
* The MIT License Copyright (c) 2014-2016 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
* associated documentation files (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge, publish, distribute,
* sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* The above copyright notice and this permission notice shall be included in all copies or
* substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
* NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package com.iluwatar.iterator;
import static com.iluwatar.iterator.list.ItemType.ANY;
import static com.iluwatar.iterator.list.ItemType.POTION;
import static com.iluwatar.iterator.list.ItemType.RING;
import static com.iluwatar.iterator.list.ItemType.WEAPON;
import com.iluwatar.iterator.bst.BstIterator;
import com.iluwatar.iterator.bst.TreeNode;
import com.iluwatar.iterator.list.Item;
import com.iluwatar.iterator.list.ItemType;
import com.iluwatar.iterator.list.TreasureChest;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
*
* The Iterator pattern is a design pattern in which an iterator is used to traverse a container and
* access the container's elements. The Iterator pattern decouples algorithms from containers.
* <p>
* In this example the Iterator ({@link ItemIterator}) adds abstraction layer on top of a collection
* In this example the Iterator ({@link Iterator}) adds abstraction layer on top of a collection
* ({@link TreasureChest}). This way the collection can change its internal implementation without
* affecting its clients.
*
*/
public class App {
private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
private static final TreasureChest TREASURE_CHEST = new TreasureChest();
private static void demonstrateTreasureChestIteratorForType(ItemType itemType) {
LOGGER.info("------------------------");
LOGGER.info("Item Iterator for ItemType " + itemType + ": ");
Iterator<Item> itemIterator = TREASURE_CHEST.iterator(itemType);
while (itemIterator.hasNext()) {
LOGGER.info(itemIterator.next().toString());
}
}
private static void demonstrateBstIterator() {
LOGGER.info("------------------------");
LOGGER.info("BST Iterator: ");
TreeNode<Integer> root = buildIntegerBst();
BstIterator bstIterator = new BstIterator<>(root);
while (bstIterator.hasNext()) {
LOGGER.info("Next node: " + bstIterator.next().getVal());
}
}
private static TreeNode<Integer> buildIntegerBst() {
TreeNode<Integer> root = new TreeNode<>(8);
root.insert(3);
root.insert(10);
root.insert(1);
root.insert(6);
root.insert(14);
root.insert(4);
root.insert(7);
root.insert(13);
return root;
}
/**
* Program entry point
*
*
* @param args command line args
*/
public static void main(String[] args) {
TreasureChest chest = new TreasureChest();
demonstrateTreasureChestIteratorForType(RING);
demonstrateTreasureChestIteratorForType(POTION);
demonstrateTreasureChestIteratorForType(WEAPON);
demonstrateTreasureChestIteratorForType(ANY);
ItemIterator ringIterator = chest.iterator(ItemType.RING);
while (ringIterator.hasNext()) {
LOGGER.info(ringIterator.next().toString());
}
LOGGER.info("----------");
ItemIterator potionIterator = chest.iterator(ItemType.POTION);
while (potionIterator.hasNext()) {
LOGGER.info(potionIterator.next().toString());
}
LOGGER.info("----------");
ItemIterator weaponIterator = chest.iterator(ItemType.WEAPON);
while (weaponIterator.hasNext()) {
LOGGER.info(weaponIterator.next().toString());
}
LOGGER.info("----------");
ItemIterator it = chest.iterator(ItemType.ANY);
while (it.hasNext()) {
LOGGER.info(it.next().toString());
}
demonstrateBstIterator();
}
}

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iterator/src/main/java/com/iluwatar/iterator/ItemIterator.java
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/**
* The MIT License
* Copyright (c) 2014-2016 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.iterator;
/**
*
* ItemIterator interface.
*
*/
public interface ItemIterator {
boolean hasNext();
Item next();
}

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iterator/src/main/java/com/iluwatar/iterator/Iterator.java Normal file
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/**
* The MIT License Copyright (c) 2014-2016 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
* associated documentation files (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge, publish, distribute,
* sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all copies or
* substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
* NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package com.iluwatar.iterator;
/**
* Iterator interface to be implemented by iterators over various data structures
* @param <T> generically typed for various objects
*/
public interface Iterator<T> {
boolean hasNext();
T next();
}

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iterator/src/main/java/com/iluwatar/iterator/bst/BstIterator.java Normal file
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/**
* The MIT License Copyright (c) 2014-2016 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
* associated documentation files (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge, publish, distribute,
* sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all copies or
* substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
* NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package com.iluwatar.iterator.bst;
import com.iluwatar.iterator.Iterator;
import java.util.ArrayDeque;
import java.util.NoSuchElementException;
/**
* An in-order implementation of a BST Iterator. For example, given a BST with Integer values,
* expect to retrieve TreeNodes according to the Integer's natural ordering (1, 2, 3...)
*
* @param <T> This Iterator has been implemented with generic typing to allow for TreeNodes of
* different value types
*/
public class BstIterator<T extends Comparable<T>> implements Iterator<TreeNode<T>> {
private ArrayDeque<TreeNode<T>> pathStack;
public BstIterator(TreeNode<T> root) {
pathStack = new ArrayDeque<>();
pushPathToNextSmallest(root);
}
/**
* This BstIterator manages to use O(h) extra space, where h is the height of the tree It achieves
* this by maintaining a stack of the nodes to handle (pushing all left nodes first), before
* handling self or right node
*
* @param node TreeNode that acts as root of the subtree we're interested in.
*/
private void pushPathToNextSmallest(TreeNode<T> node) {
while (node != null) {
pathStack.push(node);
node = node.getLeft();
}
}
/**
* @return true if this iterator has a "next" element
*/
@Override
public boolean hasNext() {
return !pathStack.isEmpty();
}
/**
* @return TreeNode next. The next element according to our in-order traversal of the given BST
* @throws NoSuchElementException if this iterator does not have a next element
*/
@Override
public TreeNode<T> next() throws NoSuchElementException {
if (pathStack.isEmpty()) {
throw new NoSuchElementException();
}
TreeNode<T> next = pathStack.pop();
pushPathToNextSmallest(next.getRight());
return next;
}
}

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iterator/src/main/java/com/iluwatar/iterator/bst/README.md Normal file
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# BSTIterator
An implementation of the Iterator design pattern, for the Binary Search Tree
data structure. A great explanation of BSTs can be found in this [video tutorial](https://www.youtube.com/watch?v=i_Q0v_Ct5lY).
### What it Does
This iterator assumes that the given binary search tree inserts nodes of smaller
value to the left, and nodes of larger value to the right of current node. Accordingly,
this iterator will return nodes according to "In Order" binary tree traversal.
This means that given a binary search tree like the following, the iterator would
return values in order: 1, 3, 4, 6, 7, 8, 10, 13, 14.
![BST](../../../../../../../etc/bst.jpg "Binary Search Tree")
### How It's Done
**The trivial solution** to a binary search tree iterator would be to construct a List (or similar
linear data structure) when you construct the BSTIterator. This would require traversing the entire
BST, adding each node value to your list as you go. The downside to the trivial solution is twofold.
You're front loading the work by requiring the BSTIterator's constructor to traverse the entire tree,
and you're taking up more memory by maintaining (worst case) every node in the tree in a separate
data structure. In Big O terms, here are the costs, where n is the number of nodes in the tree:
* Constructor Run Time: O(n)
* `next()` Run Time: O(1)
* `hasNext()` Run Time: O(1)
* Extra Space: O(n)
**A better solution** is to maintain _only_ the path to the next smallest node. For instance, given
the BST above, when you first create your BSTIterator, instead of traversing the entire tree, you
would navigate to the next smallest node (in this case, 1), pushing nodes onto a stack along the way.
Your BSTIterator Constructor would look like:
```
private ArrayDeque<TreeNode> pathStack;
public BSTIterator(TreeNode root) {
pathStack = new ArrayDeque<>();
pushPathToNextSmallest(root);
}
private void pushPathToNextSmallest(TreeNode node) {
while (node != null) {
pathStack.push(node);
node = node.getLeft();
}
}
```
After the constructor is called our BST, your `pathStack` would look like this:
1\
3\
8
This way, you're certain of what the next smallest node is because it lives on top of your path
stack. In order to maintain the integrity of this path stack, when you call `next()` and pop a
node off the stack, you must check to see if it has a right child. If it does, then you must follow the right
child's path to the next smallest node (pushing onto your path stack as you go). Given our above example,
calling `next()` on our BSTIterator twice would return node "3". Node "3" has a right child, indicating
a path to a node smaller than 3's parent. In this case, you would push node "6" onto the stack,
and node "4" onto the stack. `next()` would look like this:
```
public TreeNode next() throws IllegalStateException {
// If the user calls next() and hasNext() is false
if (pathStack.isEmpty()) {
throw new IllegalStateException();
}
TreeNode next = pathStack.pop();
// follow right child to next smallest node
pushPathToNextSmallest(next.getRight());
return next;
}
```
**Key Concept:** The path to the smallest node of a given subtree is navigating straight to the
leftmost node of that subtree.
In Big O terms, here are the costs for our improved solution, where h is the height of the tree:
* Constructor Run Time: O(h)
* `next()` Amortized Run Time: O(1)
* `hasNext()` Run Time: O(1)
* Extra Space: O(h)
As you can see, this solution more evenly distributes the work. It yields the same amortized
runtime for `next()`, reduces the run time of the constructor, and uses less extra space.

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iterator/src/main/java/com/iluwatar/iterator/bst/TreeNode.java Normal file
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@ -0,0 +1,134 @@
/**
* The MIT License Copyright (c) 2014-2016 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
* associated documentation files (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge, publish, distribute,
* sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all copies or
* substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
* NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package com.iluwatar.iterator.bst;
/**
* TreeNode Class, representing one node in a Binary Search Tree. Allows for a generically typed
* value.
*
* @param <T> generically typed to accept various data types for the val property
*/
public class TreeNode<T extends Comparable<T>> {
private T val;
private TreeNode<T> left;
private TreeNode<T> right;
/**
* Creates a TreeNode with a given value, and null children
*
* @param val The value of the given node
*/
public TreeNode(T val) {
this.val = val;
this.left = null;
this.right = null;
}
public T getVal() {
return val;
}
public TreeNode<T> getLeft() {
return left;
}
private void setLeft(TreeNode<T> left) {
this.left = left;
}
public TreeNode<T> getRight() {
return right;
}
private void setRight(TreeNode<T> right) {
this.right = right;
}
/**
* Inserts new TreeNode based on a given value into the subtree represented by self
*
* @param valToInsert The value to insert as a new TreeNode
*/
public void insert(T valToInsert) {
TreeNode<T> parent = getParentNodeOfValueToBeInserted(valToInsert);
parent.insertNewChild(valToInsert);
}
/**
* Fetch the Parent TreeNode for a given value to insert into the BST.
*
* @param valToInsert Value of the new TreeNode to be inserted
* @return Parent TreeNode of `valToInsert`
*/
private TreeNode<T> getParentNodeOfValueToBeInserted(T valToInsert) {
TreeNode<T> parent = null;
TreeNode<T> curr = this;
while (curr != null) {
parent = curr;
curr = curr.traverseOneLevelDown(valToInsert);
}
return parent;
}
/**
* Returns left or right child of self based on a value that would be inserted; maintaining the
* integrity of the BST.
*
* @param value The value of the TreeNode that would be inserted beneath self
* @return The child TreeNode of self which represents the subtree where `value` would be inserted
*/
private TreeNode<T> traverseOneLevelDown(T value) {
if (this.isGreaterThan(value)) {
return this.left;
}
return this.right;
}
/**
* Add a new Child TreeNode of given value to self. WARNING: This method is destructive (will
* overwrite existing tree structure, if any), and should be called only by this class's insert()
* method.
*
* @param valToInsert Value of the new TreeNode to be inserted
*/
private void insertNewChild(T valToInsert) {
if (this.isLessThanOrEqualTo(valToInsert)) {
this.setRight(new TreeNode<>(valToInsert));
} else {
this.setLeft(new TreeNode<>(valToInsert));
}
}
private boolean isGreaterThan(T val) {
return this.val.compareTo(val) > 0;
}
private boolean isLessThanOrEqualTo(T val) {
return this.val.compareTo(val) < 1;
}
@Override
public String toString() {
return val.toString();
}
}

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iterator/src/main/java/com/iluwatar/iterator/Item.java → iterator/src/main/java/com/iluwatar/iterator/list/Item.java
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@ -20,7 +20,7 @@
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.iterator;
package com.iluwatar.iterator.list;
/**
*

2
iterator/src/main/java/com/iluwatar/iterator/ItemType.java → iterator/src/main/java/com/iluwatar/iterator/list/ItemType.java
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@ -20,7 +20,7 @@
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.iterator;
package com.iluwatar.iterator.list;
/**
*

41
iterator/src/main/java/com/iluwatar/iterator/TreasureChest.java → iterator/src/main/java/com/iluwatar/iterator/list/TreasureChest.java
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@ -1,34 +1,31 @@
/**
* The MIT License
* Copyright (c) 2014-2016 Ilkka Seppälä
* The MIT License Copyright (c) 2014-2016 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
* associated documentation files (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge, publish, distribute,
* sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* The above copyright notice and this permission notice shall be included in all copies or
* substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
* NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package com.iluwatar.iterator;
package com.iluwatar.iterator.list;
import com.iluwatar.iterator.Iterator;
import java.util.ArrayList;
import java.util.List;
/**
*
*
* TreasureChest, the collection class.
*
*
*/
public class TreasureChest {
@ -51,7 +48,7 @@ public class TreasureChest {
items.add(new Item(ItemType.WEAPON, "Dagger of poison"));
}
ItemIterator iterator(ItemType itemType) {
public Iterator<Item> iterator(ItemType itemType) {
return new TreasureChestItemIterator(this, itemType);
}
@ -59,9 +56,7 @@ public class TreasureChest {
* Get all items
*/
public List<Item> getItems() {
List<Item> list = new ArrayList<>();
list.addAll(items);
return list;
return new ArrayList<>(items);
}
}

36
iterator/src/main/java/com/iluwatar/iterator/TreasureChestItemIterator.java → iterator/src/main/java/com/iluwatar/iterator/list/TreasureChestItemIterator.java
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@ -1,35 +1,32 @@
/**
* The MIT License
* Copyright (c) 2014-2016 Ilkka Seppälä
* The MIT License Copyright (c) 2014-2016 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
* associated documentation files (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge, publish, distribute,
* sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* The above copyright notice and this permission notice shall be included in all copies or
* substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
* NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package com.iluwatar.iterator;
package com.iluwatar.iterator.list;
import com.iluwatar.iterator.Iterator;
import java.util.List;
/**
*
*
* TreasureChestItemIterator
*
*/
public class TreasureChestItemIterator implements ItemIterator {
public class TreasureChestItemIterator implements Iterator<Item> {
private TreasureChest chest;
private int idx;
@ -59,7 +56,6 @@ public class TreasureChestItemIterator implements ItemIterator {
}
private int findNextIdx() {
List<Item> items = chest.getItems();
boolean found = false;
int tempIdx = idx;

45
iterator/src/test/java/com/iluwatar/iterator/AppTest.java
View File

@ -1,39 +1,34 @@
/**
* The MIT License
* Copyright (c) 2014-2016 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* The MIT License Copyright (c) 2014-2016 Ilkka Seppälä
* <p>
* Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
* associated documentation files (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge, publish, distribute,
* sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
* <p>
* The above copyright notice and this permission notice shall be included in all copies or
* substantial portions of the Software.
* <p>
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
* NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package com.iluwatar.iterator;
import org.junit.jupiter.api.Test;
/**
*
* Application test
*
* Application Test
*/
public class AppTest {
class AppTest {
@Test
public void test() {
void testApp() {
String[] args = {};
App.main(args);
}
}
}

99
iterator/src/test/java/com/iluwatar/iterator/bst/BstIteratorTest.java Normal file
View File

@ -0,0 +1,99 @@
/**
* The MIT License Copyright (c) 2014-2016 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
* associated documentation files (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge, publish, distribute,
* sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all copies or
* substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
* NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package com.iluwatar.iterator.bst;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.TestInstance;
import org.junit.jupiter.api.TestInstance.Lifecycle;
import java.util.NoSuchElementException;
@TestInstance(Lifecycle.PER_CLASS)
class BstIteratorTest {
private TreeNode<Integer> nonEmptyRoot;
private TreeNode<Integer> emptyRoot;
@BeforeAll
void createTrees() {
nonEmptyRoot = new TreeNode<>(5);
nonEmptyRoot.insert(3);
nonEmptyRoot.insert(7);
nonEmptyRoot.insert(1);
nonEmptyRoot.insert(4);
nonEmptyRoot.insert(6);
emptyRoot = null;
}
@Test
void nextForEmptyTree() {
BstIterator iter = new BstIterator<>(emptyRoot);
assertThrows(NoSuchElementException.class, iter::next,
"next() should throw an IllegalStateException if hasNext() is false.");
}
@Test
void nextOverEntirePopulatedTree() {
BstIterator iter = new BstIterator<>(nonEmptyRoot);
assertEquals(1, iter.next().getVal(), "First Node is 1.");
assertEquals(3, iter.next().getVal(), "Second Node is 3.");
assertEquals(4, iter.next().getVal(), "Third Node is 4.");
assertEquals(5, iter.next().getVal(), "Fourth Node is 5.");
assertEquals(6, iter.next().getVal(), "Fifth Node is 6.");
assertEquals(7, iter.next().getVal(), "Sixth Node is 7.");
}
@Test
void hasNextForEmptyTree() {
BstIterator iter = new BstIterator<>(emptyRoot);
assertFalse(iter.hasNext(), "hasNext() should return false for empty tree.");
}
@Test
void hasNextForPopulatedTree() {
BstIterator iter = new BstIterator<>(nonEmptyRoot);
assertTrue(iter.hasNext(), "hasNext() should return true for populated tree.");
}
@Test
void nextAndHasNextOverEntirePopulatedTree() {
BstIterator iter = new BstIterator<>(nonEmptyRoot);
assertTrue(iter.hasNext(), "Iterator hasNext() should be true.");
assertEquals(1, iter.next().getVal(), "First Node is 1.");
assertTrue(iter.hasNext(), "Iterator hasNext() should be true.");
assertEquals(3, iter.next().getVal(), "Second Node is 3.");
assertTrue(iter.hasNext(), "Iterator hasNext() should be true.");
assertEquals(4, iter.next().getVal(), "Third Node is 4.");
assertTrue(iter.hasNext(), "Iterator hasNext() should be true.");
assertEquals(5, iter.next().getVal(), "Fourth Node is 5.");
assertTrue(iter.hasNext(), "Iterator hasNext() should be true.");
assertEquals(6, iter.next().getVal(), "Fifth Node is 6.");
assertTrue(iter.hasNext(), "Iterator hasNext() should be true.");
assertEquals(7, iter.next().getVal(), "Sixth Node is 7.");
assertFalse(iter.hasNext(), "Iterator hasNext() should be false, end of tree.");
}
}

47
iterator/src/test/java/com/iluwatar/iterator/TreasureChestTest.java → iterator/src/test/java/com/iluwatar/iterator/list/TreasureChestTest.java
View File

@ -1,37 +1,33 @@
/**
* The MIT License
* Copyright (c) 2014-2016 Ilkka Seppälä
* The MIT License Copyright (c) 2014-2016 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
* associated documentation files (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge, publish, distribute,
* sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* The above copyright notice and this permission notice shall be included in all copies or
* substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
* NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package com.iluwatar.iterator;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.MethodSource;
import java.util.ArrayList;
import java.util.List;
package com.iluwatar.iterator.list;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.fail;
import com.iluwatar.iterator.Iterator;
import java.util.ArrayList;
import java.util.List;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.MethodSource;
/**
* Date: 12/14/15 - 2:58 PM
*
@ -60,13 +56,14 @@ public class TreasureChestTest {
}
/**
* Test if the expected item can be retrieved from the chest using the {@link ItemIterator}
* Test if the expected item can be retrieved from the chest using the {@link
* TreasureChestItemIterator}
*/
@ParameterizedTest
@MethodSource("dataProvider")
public void testIterator(Item expectedItem) {
final TreasureChest chest = new TreasureChest();
final ItemIterator iterator = chest.iterator(expectedItem.getType());
final Iterator<Item> iterator = chest.iterator(expectedItem.getType());
assertNotNull(iterator);
while (iterator.hasNext()) {