Java02. ДЗ 01, Shevchenko Ilya

MyHashMap/build.gradle

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+group 'ru.spbau.shevchenko'
+version '1.0-SNAPSHOT'
+
+apply plugin: 'java'
+
+sourceCompatibility = 1.8
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testCompile group: 'junit', name: 'junit', version: '4.11'
+}

MyHashMap/gradle/wrapper/gradle-wrapper.properties

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+#Tue Dec 06 19:55:43 MSK 2016
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-2.13-bin.zip

MyHashMap/settings.gradle

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+rootProject.name = 'MyHashMap'
+

MyHashMap/src/main/java/MyHashMap.java

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+public class MyHashMap {
+
+    // хеш-таблица, использующая список
+    // ключами и значениями выступают строки
+    // стандартный способ получить хеш объекта -- вызвать у него метод hashCode()
+    // сейчас все методы бросают исключение
+    // это сделано, чтобы код компилировался, в конечном коде такого исключения быть не должно
+
+    private MyLinkedList[] lists;
+
+    private int keyCount;
+    private int capacity;
+
+    public MyHashMap(int capacity){
+        this.capacity = capacity;
+        keyCount = 0;
+        lists = new MyLinkedList[capacity];
+    }
+
+    public int size() {
+        return keyCount;
+    }
+
+    private int getIndex(String key){
+        return key.hashCode() % capacity;
+    }
+
+    public boolean contains(String key) {
+        MyLinkedList list = lists[getIndex(key)];
+        if (list == null){
+            return false;
+        }
+        MyNode current = list.getHead();
+        while (current != null){
+            if (current.first.equals(key)){
+                return true;
+            }
+            current = current.next;
+        }
+        return false;
+    }
+
+    public String get(String key) {
+        MyLinkedList list = lists[getIndex(key)];
+        if (list == null){
+            return null;
+        }
+        MyNode current = list.getHead();
+        while (current != null){
+            if (current.first.equals(key)){
+                return current.second;
+            }
+            current = current.next;
+        }
+        return null;
+    }
+
+    public String put(String key, String value) {
+        MyLinkedList list = lists[getIndex(key)];
+        if (list == null){
+            list = new MyLinkedList();
+            lists[getIndex(key)] = list;
+        }
+        MyNode current = list.getHead();
+        while (current != null){
+            if (current.first.equals(key)){
+                String result = current.second;
+                current.second = value;
+                return result;
+            }
+            current = current.next;
+        }
+        list.add(key, value);
+        keyCount++;
+        return null;
+    }
+
+    public String remove(String key) {
+        MyLinkedList list = lists[getIndex(key)];
+        if (list == null){
+            return null;
+        }
+        MyNode current = list.getHead();
+        while (current != null){
+            if (current.first.equals(key)){
+                list.remove(current);
+                keyCount--;
+                return current.second;
+            }
+            current = current.next;
+        }
+
+        return null;
+    }
+
+    public void clear() {
+        lists = new MyLinkedList[capacity];
+        keyCount = 0;
+    }
+}