import gnu.trove.stack.TCharStack; //导入依赖的package包/类
/**
 * Creates a new <code>TCharArrayStack</code> instance that is
 * a copy of the instanced passed to us.
 *
 * @param stack the instance to copy
 */
public TCharArrayStack( TCharStack stack ) {
    if ( stack instanceof TCharArrayStack ) {
        TCharArrayStack array_stack = ( TCharArrayStack ) stack;
        this._list = new TCharArrayList( array_stack._list );
    } else {
        throw new UnsupportedOperationException( "Only support TCharArrayStack" );
    }
}