Reset size to 0 when clearing table
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parent
13991b6bd2
commit
1d0e670597
1 changed files with 130 additions and 129 deletions
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@ -1,129 +1,130 @@
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package ch.nuth.zhaw.exbox;
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import java.util.Collection;
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import java.util.Map;
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import java.util.Set;
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@SuppressWarnings("unchecked")
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public class MyHashtable<K, V> implements Map<K, V> {
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private int capacity;
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private int size;
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private K[] keys = (K[]) new Object[10];
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private V[] values = (V[]) new Object[10];
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public MyHashtable(int size) {
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capacity = size;
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clear();
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}
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private boolean hashEquals(Object x, Object y) {
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if (x == null || y == null) {
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return x == y;
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} else {
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return x.hashCode() == y.hashCode();
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}
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}
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private int hash(Object k) {
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int h = Math.abs(k.hashCode());
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return h % keys.length;
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}
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// Removes all mappings from this map (optional operation).
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public void clear() {
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keys = (K[]) new Object[capacity];
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values = (V[]) new Object[capacity];
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}
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// Associates the specified value with the specified key in this map (optional
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// operation).
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public V put(K key, V value) {
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int hashCode = hash(key);
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int index = hashCode;
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for (int i = 0; keys[index] != null && !hashEquals(keys[index], key); i++) {
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index = hash(hashCode + (int) Math.pow(i, 2));
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}
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if (keys[index] == null) {
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size++;
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}
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keys[index] = key;
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values[index] = value;
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return value;
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}
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// Returns the value to which this map maps the specified key.
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public V get(Object key) {
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// to be done
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for (int i = 0; i < keys.length; i++) {
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if (hashEquals(key, keys[i])) {
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return values[i];
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}
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}
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return null;
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}
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// Removes the mapping for this key from this map if present (optional
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// operation).
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public V remove(Object key) {
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// to be done (Aufgabe 3)
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throw new UnsupportedOperationException();
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}
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// Returns the number of key-value mappings in this map.
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public int size() {
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return size;
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}
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// UnsupportedOperationException
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// ===================================================================
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// Returns a collection view of the values contained in this map.
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public Collection<V> values() {
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throw new UnsupportedOperationException();
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}
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// Returns true if this map contains a mapping for the specified key.
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public boolean containsKey(Object key) {
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throw new UnsupportedOperationException();
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}
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// Returns true if this map maps one or more keys to the specified value.
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public boolean containsValue(Object value) {
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throw new UnsupportedOperationException();
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}
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// Returns a set view of the mappings contained in this map.
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public Set<Map.Entry<K, V>> entrySet() {
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throw new UnsupportedOperationException();
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}
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// Compares the specified object with this map for equality.
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public boolean equals(Object o) {
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throw new UnsupportedOperationException();
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}
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// Copies all of the mappings from the specified map to this map (optional
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// operation).
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public void putAll(Map<? extends K, ? extends V> t) {
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throw new UnsupportedOperationException();
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}
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// Returns the hash code value for this map.
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public int hashCode() {
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throw new UnsupportedOperationException();
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}
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// Returns true if this map contains no key-value mappings.
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public boolean isEmpty() {
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throw new UnsupportedOperationException();
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}
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// Returns a set view of the keys contained in this map.
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public Set<K> keySet() {
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throw new UnsupportedOperationException();
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}
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}
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package ch.nuth.zhaw.exbox;
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import java.util.Collection;
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import java.util.Map;
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import java.util.Set;
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@SuppressWarnings("unchecked")
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public class MyHashtable<K, V> implements Map<K, V> {
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private int capacity;
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private int size;
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private K[] keys = (K[]) new Object[10];
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private V[] values = (V[]) new Object[10];
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public MyHashtable(int size) {
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capacity = size;
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clear();
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}
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private boolean hashEquals(Object x, Object y) {
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if (x == null || y == null) {
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return x == y;
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} else {
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return x.hashCode() == y.hashCode();
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}
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}
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private int hash(Object k) {
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int h = Math.abs(k.hashCode());
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return h % keys.length;
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}
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// Removes all mappings from this map (optional operation).
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public void clear() {
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size = 0;
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keys = (K[]) new Object[capacity];
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values = (V[]) new Object[capacity];
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}
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// Associates the specified value with the specified key in this map (optional
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// operation).
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public V put(K key, V value) {
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int hashCode = hash(key);
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int index = hashCode;
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for (int i = 0; keys[index] != null && !hashEquals(keys[index], key); i++) {
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index = hash(hashCode + (int) Math.pow(i, 2));
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}
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if (keys[index] == null) {
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size++;
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}
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keys[index] = key;
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values[index] = value;
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return value;
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}
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// Returns the value to which this map maps the specified key.
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public V get(Object key) {
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// to be done
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for (int i = 0; i < keys.length; i++) {
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if (hashEquals(key, keys[i])) {
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return values[i];
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}
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}
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return null;
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}
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// Removes the mapping for this key from this map if present (optional
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// operation).
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public V remove(Object key) {
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// to be done (Aufgabe 3)
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throw new UnsupportedOperationException();
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}
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// Returns the number of key-value mappings in this map.
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public int size() {
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return size;
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}
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// UnsupportedOperationException
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// ===================================================================
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// Returns a collection view of the values contained in this map.
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public Collection<V> values() {
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throw new UnsupportedOperationException();
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}
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// Returns true if this map contains a mapping for the specified key.
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public boolean containsKey(Object key) {
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throw new UnsupportedOperationException();
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}
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// Returns true if this map maps one or more keys to the specified value.
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public boolean containsValue(Object value) {
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throw new UnsupportedOperationException();
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}
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// Returns a set view of the mappings contained in this map.
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public Set<Map.Entry<K, V>> entrySet() {
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throw new UnsupportedOperationException();
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}
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// Compares the specified object with this map for equality.
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public boolean equals(Object o) {
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throw new UnsupportedOperationException();
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}
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// Copies all of the mappings from the specified map to this map (optional
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// operation).
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public void putAll(Map<? extends K, ? extends V> t) {
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throw new UnsupportedOperationException();
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}
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// Returns the hash code value for this map.
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public int hashCode() {
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throw new UnsupportedOperationException();
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}
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// Returns true if this map contains no key-value mappings.
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public boolean isEmpty() {
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throw new UnsupportedOperationException();
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}
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// Returns a set view of the keys contained in this map.
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public Set<K> keySet() {
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throw new UnsupportedOperationException();
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}
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}
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