Adapter 패턴

Author: holmir97

Adapter Pattern/src/DataCollection.java

@@ -0,0 +1,8 @@
+import java.util.Iterator;
+
+public interface DataCollection<T> {
+    boolean put(T t);
+    T elemAt(int index);
+    int length();
+    Iterator createIterator();
+}

Adapter Pattern/src/DataCollectionAdapter.java

@@ -0,0 +1,63 @@
+import java.util.ArrayList;
+import java.util.Iterator;
+
+public class DataCollectionAdapter<T> implements DataCollection<T> {
+    final int SIZE = 3;
+    private int length;
+    private int capacity;
+    private ArrayList<T> data;
+
+    public DataCollectionAdapter(){
+        data = new ArrayList<T>(SIZE);
+        length = 0;
+        capacity = SIZE;
+    }
+    @Override
+    public boolean put(T t) {
+        if (length >= capacity) {
+            boolean b = resizeArray(); // 재할당
+            if (b) {
+                data.add(t);
+                length++;
+            }
+            return b;
+        }
+        else {
+            data.add(t);
+            length++;
+        }
+        return true;
+    }
+
+    @Override
+    public T elemAt(int index) {
+        if (index >= 0 && index < length) {
+            return (T) data.get(index);
+        }
+        return null;
+    }
+
+    @Override
+    public int length() {
+        return length;
+    }
+
+    @Override
+    public Iterator createIterator() {
+        Iterator<T> itr = data.iterator();
+        return itr;
+    }
+
+    private boolean resizeArray() {
+        ArrayList<T> newData = new ArrayList<T>(capacity + SIZE);
+        if (newData == null) {
+            return false;
+        }
+        for (int i = 0; i < capacity; i++) {
+            newData.add(data.get(i));
+        }
+        data = newData;
+        capacity += SIZE;
+        return true;
+    }
+}

Adapter Pattern/src/DynamicArray.java

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+import java.util.Iterator;
+
+//DynamicArray<String> strArray = new DynamicArray<String>();
+//DynamicArray<Integer> intArray = new DynamicArray<Integer>();
+
+public class DynamicArray<T> implements DataCollection<T> {
+    final int SIZE = 3;
+    private int length;
+    private int capacity;
+    private Object[] data;
+
+    public DynamicArray() {
+        data = new Object[SIZE];
+        length = 0;
+        capacity = SIZE;
+    }
+
+    public boolean put(T t) {
+        if (length >= capacity) {
+            boolean b = resizeArray(); // 재할당
+            if (b) {
+                data[length] = t;
+                length++;
+            }
+            return b;
+        }
+        else {
+            data[length] = t;
+            length++;
+        }
+        return true;
+    }
+
+    public T elemAt(int index) {
+        if (index >= 0 && index < length) {
+            return (T) data[index];
+        }
+        return null;
+    }
+
+    public int length() {
+        return length;
+    }
+
+    public Iterator createIterator() {
+        return new DynamicArrayIterator(this);
+    }
+
+    private boolean resizeArray() {
+        Object[] newData = new Object[capacity + SIZE];
+        if (newData == null) {
+            return false;
+        }
+        for (int i = 0; i < capacity; i++) {
+            newData[i] = data[i];
+        }
+        data = newData;
+        capacity += SIZE;
+        return true;
+    }
+}

Adapter Pattern/src/DynamicArrayIterator.java

@@ -0,0 +1,28 @@
+import java.util.Iterator;
+
+public class DynamicArrayIterator implements Iterator {
+    private DynamicArray array;
+    private int index;
+
+    public DynamicArrayIterator(DynamicArray arr) {
+        array = arr;
+        index = 0;
+    }
+
+    @Override
+    public boolean hasNext() {
+        return (index < array.length());
+    }
+
+    @Override
+    public Object next() {
+        Object obj = array.elemAt(index);
+        index++;
+        return obj;
+    }
+
+    @Override
+    public void remove() {
+        //throw new UnsupportedOperationException();
+    }
+}

Adapter Pattern/src/TestDynamicArray.java

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+import java.util.Iterator;
+
+public class TestDynamicArray {
+    public static void main(String[] args) {
+        DataCollection<String> arr1 = new DynamicArray<String>();
+        arr1.put("Seoul");
+        arr1.put("Busan");
+        arr1.put("Gwangju");
+        arr1.put("Daejeon");
+        arr1.put("Cheonan");
+        arr1.put("Ulsan");
+        arr1.put("Daegu");
+        arr1.put("Incheon");
+
+
+
+        System.out.println("\n변경 전:  DynamicArray를 이용");
+        System.out.println("--------------------------------");
+        System.out.println("index");
+        for (int i = 0; i < arr1.length(); i++) {
+            String s = (String) arr1.elemAt(i);
+            System.out.println(s);
+        }
+
+
+        System.out.println("--------------------------------");
+        System.out.println("iterator");
+        for (Iterator iter = arr1.createIterator(); iter.hasNext(); ) {
+            String s = (String) iter.next();
+            System.out.println(s);
+        }
+
+
+        DataCollection<String> arr2 = new DataCollectionAdapter<String>();
+        arr2.put("Seoul");
+        arr2.put("Busan");
+        arr2.put("Gwangju");
+        arr2.put("Daejeon");
+        arr2.put("Cheonan");
+        arr2.put("Ulsan");
+        arr2.put("Daegu");
+        arr2.put("Incheon");
+
+
+
+        System.out.println("\n변경 후:  DataCollectionAdapter를 이용");
+        System.out.println("--------------------------------");
+        System.out.println("index");
+        for (int i = 0; i < arr2.length(); i++) {
+            String s = (String) arr2.elemAt(i);
+            System.out.println(s);
+        }
+
+        System.out.println("--------------------------------");
+        System.out.println("iterator");
+        for (Iterator iter = arr2.createIterator(); iter.hasNext(); ) {
+            String s = (String) iter.next();
+            System.out.println(s);
+        }
+    }
+}