class CacheEntryImpl<K, V> implements Cache.Entry<K, V>, Externalizable {
    /** */
    private static final long serialVersionUID = 0L;

    /** */
    private K key;

    /** */
    private V val;

    /** Entry version. */
    private GridCacheVersion ver;

    /**
     * Required by {@link Externalizable}.
     */
    public CacheEntryImpl() {
        // No-op.
    }

    /**
     * @param key Key.
     * @param val Value.
     */
    public CacheEntryImpl(K key, V val) {
        this.key = key;
        this.val = val;
    }

    /**
     * @param key Key.
     * @param val Value.
     * @param ver Entry version.
     */
    public CacheEntryImpl(K key, V val, GridCacheVersion ver) {
        this.key = key;
        this.val = val;
        this.ver = ver;
    }

    /** {@inheritDoc} */
    @Override public K getKey() {
        return key;
    }

    /** {@inheritDoc} */
    @Override public V getValue() {
        return val;
    }

    /** {@inheritDoc} */
    @Override public <T> T unwrap(Class<T> cls) {<FILL_FUNCTION_BODY>}

    /** {@inheritDoc} */
    @Override public void writeExternal(ObjectOutput out) throws IOException {
        out.writeObject(key);
        out.writeObject(val);
    }

    /** {@inheritDoc} */
    @Override public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
        key = (K)in.readObject();
        val = (V)in.readObject();
    }

    /** {@inheritDoc} */
    @Override public String toString() {
        return "Entry [key=" + key + ", val=" + val + ']';
    }
}

        if (cls.isAssignableFrom(getClass()))
            return cls.cast(this);

        if (cls.isAssignableFrom(CacheEntry.class))
            return (T)new CacheEntryImplEx<>(key, val, ver);

        throw new IllegalArgumentException("Unwrapping to class is not supported: " + cls);
    
<no_super_class>