/**
* Copyright (C) 2022 by Martin Robillard. See https://codesample.info/about.html
*/
package e2.chapter7;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
/**
* Represents a deck of playing cards that can be inherited and polymorphically copied.
*/
public class Deck implements CardSource, Iterable<Card>, Cloneable {
private CardStack aCards = new CardStack();
/**
* Creates a new deck of 52 cards, shuffled.
*/
public Deck() {
shuffle();
}
/**
* Reinitializes the deck with all 52 cards, and shuffles them.
*/
public void shuffle() {
List<Card> cards = new ArrayList<>();
for( Suit suit : Suit.values() ) {
for( Rank rank : Rank.values() ) {
cards.add( Card.get( rank, suit ));
}
}
Collections.shuffle(cards);
aCards = new CardStack(cards);
}
/**
* Draws a card from the deck: removes the card from the top
* of the deck and returns it.
* @return The card drawn.
* @pre !isEmpty()
*/
@Override
public Card draw() {
assert !isEmpty();
return aCards.pop();
}
/**
* @return True if and only if there are no cards in the deck.
*/
@Override
public boolean isEmpty() {
return aCards.isEmpty();
}
@Override
public Iterator<Card> iterator() {
return aCards.iterator();
}
@Override
public Deck clone()
{
try
{
Deck clone = (Deck) super.clone();
clone.aCards = new CardStack(aCards);
return clone;
}
catch( CloneNotSupportedException e )
{
assert false;
return null;
}
}
}
List
interface. Implements all optional list operations, and permits all elements, including null
. In addition to implementing the List
interface, this class provides methods to manipulate the size of the array that is used internally to store the list. (This class is roughly equivalent to Vector
, except that it is unsynchronized.)
List
interface. Implements all optional list operations, and permits all elements, including null
. In addition to implementing the List
interface, this class provides methods to manipulate the size of the array that is used internally to store the list. (This class is roughly equivalent to Vector
, except that it is unsynchronized.)
The size
, isEmpty
, get
, set
, iterator
, and listIterator
operations run in constant time. The add
operation runs in amortized constant time, that is, adding n elements requires O(n) time. All of the other operations run in linear time (roughly speaking). The constant factor is low compared to that for the LinkedList
implementation.
Each ArrayList
instance has a capacity. The capacity is the size of the array used to store the elements in the list. It is always at least as large as the list size. As elements are added to an ArrayList, its capacity grows automatically. The details of the growth policy are not specified beyond the fact that adding an element has constant amortized time cost.
An application can increase the capacity of an ArrayList
instance before adding a large number of elements using the ensureCapacity
operation. This may reduce the amount of incremental reallocation.
Note that this implementation is not synchronized. If multiple threads access an ArrayList
instance concurrently, and at least one of the threads modifies the list structurally, it must be synchronized externally. (A structural modification is any operation that adds or deletes one or more elements, or explicitly resizes the backing array; merely setting the value of an element is not a structural modification.) This is typically accomplished by synchronizing on some object that naturally encapsulates the list. If no such object exists, the list should be "wrapped" using the Collections.synchronizedList
method. This is best done at creation time, to prevent accidental unsynchronized access to the list:
List list = Collections.synchronizedList(new ArrayList(...));
The iterators returned by this class's iterator
and listIterator
methods are fail-fast: if the list is structurally modified at any time after the iterator is created, in any way except through the iterator's own remove
or add
methods, the iterator will throw a ConcurrentModificationException
. Thus, in the face of concurrent modification, the iterator fails quickly and cleanly, rather than risking arbitrary, non-deterministic behavior at an undetermined time in the future.
Note that the fail-fast behavior of an iterator cannot be guaranteed as it is, generally speaking, impossible to make any hard guarantees in the presence of unsynchronized concurrent modification. Fail-fast iterators throw ConcurrentModificationException
on a best-effort basis. Therefore, it would be wrong to write a program that depended on this exception for its correctness: the fail-fast behavior of iterators should be used only to detect bugs.
This class is a member of the Java Collections Framework.
Unlike sets, lists typically allow duplicate elements. More formally, lists typically allow pairs of elements e1
and e2
such that e1.equals(e2)
, and they typically allow multiple null elements if they allow null elements at all. It is not inconceivable that someone might wish to implement a list that prohibits duplicates, by throwing runtime exceptions when the user attempts to insert them, but we expect this usage to be rare.
The List
interface places additional stipulations, beyond those specified in the Collection
interface, on the contracts of the iterator
, add
, remove
, equals
, and hashCode
methods. Declarations for other inherited methods are also included here for convenience.
The List
interface provides four methods for positional (indexed) access to list elements. Lists (like Java arrays) are zero based. Note that these operations may execute in time proportional to the index value for some implementations (the LinkedList
class, for example). Thus, iterating over the elements in a list is typically preferable to indexing through it if the caller does not know the implementation.
The List
interface provides a special iterator, called a ListIterator
, that allows element insertion and replacement, and bidirectional access in addition to the normal operations that the Iterator
interface provides. A method is provided to obtain a list iterator that starts at a specified position in the list.
The List
interface provides two methods to search for a specified object. From a performance standpoint, these methods should be used with caution. In many implementations they will perform costly linear searches.
The List
interface provides two methods to efficiently insert and remove multiple elements at an arbitrary point in the list.
Note: While it is permissible for lists to contain themselves as elements, extreme caution is advised: the equals
and hashCode
methods are no longer well defined on such a list.
Some list implementations have restrictions on the elements that they may contain. For example, some implementations prohibit null elements, and some have restrictions on the types of their elements. Attempting to add an ineligible element throws an unchecked exception, typically NullPointerException
or ClassCastException
. Attempting to query the presence of an ineligible element may throw an exception, or it may simply return false; some implementations will exhibit the former behavior and some will exhibit the latter. More generally, attempting an operation on an ineligible element whose completion would not result in the insertion of an ineligible element into the list may throw an exception or it may succeed, at the option of the implementation. Such exceptions are marked as "optional" in the specification for this interface.
The List.of
and List.copyOf
static factory methods provide a convenient way to create unmodifiable lists. The List
instances created by these methods have the following characteristics:
UnsupportedOperationException
to be thrown. However, if the contained elements are themselves mutable, this may cause the List's contents to appear to change. null
elements. Attempts to create them with null
elements result in NullPointerException
. subList
views implement the RandomAccess
interface. This interface is a member of the Java Collections Framework.
Lists that support this operation may place limitations on what elements may be added to this list. In particular, some lists will refuse to add null elements, and others will impose restrictions on the type of elements that may be added. List classes should clearly specify in their documentation any restrictions on what elements may be added.
add
in interface Collection<E>
e
- element to be appended to this list
true
(as specified by Collection.add(E)
)
UnsupportedOperationException
- if the add
operation is not supported by this list
ClassCastException
- if the class of the specified element prevents it from being added to this list
NullPointerException
- if the specified element is null and this list does not permit null elements
IllegalArgumentException
- if some property of this element prevents it from being added to this list
Iterator
takes the place of Enumeration
in the Java Collections Framework. Iterators differ from enumerations in two ways:
Iterator
takes the place of Enumeration
in the Java Collections Framework. Iterators differ from enumerations in two ways:
This interface is a member of the Java Collections Framework.
Enumeration
can be converted into an Iterator
by using the Enumeration.asIterator()
method.
Cloneable
interface to
indicate to the Object.clone()
method that it
is legal for that method to make a
field-for-field copy of instances of that class.
Cloneable
interface to
indicate to the Object.clone()
method that it
is legal for that method to make a
field-for-field copy of instances of that class.
Invoking Object's clone method on an instance that does not implement the
Cloneable
interface results in the exception
CloneNotSupportedException
being thrown.
By convention, classes that implement this interface should override
Object.clone
(which is protected) with a public method.
See Object.clone()
for details on overriding this
method.
Note that this interface does not contain the clone
method.
Therefore, it is not possible to clone an object merely by virtue of the
fact that it implements this interface. Even if the clone method is invoked
reflectively, there is no guarantee that it will succeed.
The methods of this class all throw a NullPointerException
if the collections or class objects provided to them are null.
The documentation for the polymorphic algorithms contained in this class generally includes a brief description of the implementation. Such descriptions should be regarded as implementation notes, rather than parts of the specification. Implementors should feel free to substitute other algorithms, so long as the specification itself is adhered to. (For example, the algorithm used by sort
does not have to be a mergesort, but it does have to be stable.)
The "destructive" algorithms contained in this class, that is, the algorithms that modify the collection on which they operate, are specified to throw UnsupportedOperationException
if the collection does not support the appropriate mutation primitive(s), such as the set
method. These algorithms may, but are not required to, throw this exception if an invocation would have no effect on the collection. For example, invoking the sort
method on an unmodifiable list that is already sorted may or may not throw UnsupportedOperationException
.
This class is a member of the Java Collections Framework.
The hedge "approximately" is used in the foregoing description because default source of randomness is only approximately an unbiased source of independently chosen bits. If it were a perfect source of randomly chosen bits, then the algorithm would choose permutations with perfect uniformity.
This implementation traverses the list backwards, from the last element up to the second, repeatedly swapping a randomly selected element into the "current position". Elements are randomly selected from the portion of the list that runs from the first element to the current position, inclusive.
RandomAccess
interface and is large, this implementation dumps the specified list into an array before shuffling it, and dumps the shuffled array back into the list. This avoids the quadratic behavior that would result from shuffling a "sequential access" list in place.
list
- the list to be shuffled.
UnsupportedOperationException
- if the specified list or its list-iterator does not support the set
operation.
clone
method in class
Object
has been called to clone an object, but that
the object's class does not implement the Cloneable
interface.
clone
method in class
Object
has been called to clone an object, but that
the object's class does not implement the Cloneable
interface.
Applications that override the clone
method can also
throw this exception to indicate that an object could not or
should not be cloned.
x
, the expression:
x
, the expression:
will be true, and that the expression:x.clone() != x
will bex.clone().getClass() == x.getClass()
true
, but these are not absolute requirements. While it is typically the case that:
will bex.clone().equals(x)
true
, this is not an absolute requirement.
By convention, the returned object should be obtained by calling super.clone
. If a class and all of its superclasses (except Object
) obey this convention, it will be the case that x.clone().getClass() == x.getClass()
.
By convention, the object returned by this method should be independent of this object (which is being cloned). To achieve this independence, it may be necessary to modify one or more fields of the object returned by super.clone
before returning it. Typically, this means copying any mutable objects that comprise the internal "deep structure" of the object being cloned and replacing the references to these objects with references to the copies. If a class contains only primitive fields or references to immutable objects, then it is usually the case that no fields in the object returned by super.clone
need to be modified.
clone
for class Object
performs a specific cloning operation. First, if the class of this object does not implement the interface Cloneable
, then a CloneNotSupportedException
is thrown. Note that all arrays are considered to implement the interface Cloneable
and that the return type of the clone
method of an array type T[]
is T[]
where T is any reference or primitive type. Otherwise, this method creates a new instance of the class of this object and initializes all its fields with exactly the contents of the corresponding fields of this object, as if by assignment; the contents of the fields are not themselves cloned. Thus, this method performs a "shallow copy" of this object, not a "deep copy" operation.
The class Object
does not itself implement the interface Cloneable
, so calling the clone
method on an object whose class is Object
will result in throwing an exception at run time.
CloneNotSupportedException
- if the object's class does not support the Cloneable
interface. Subclasses that override the clone
method can also throw this exception to indicate that an instance cannot be cloned.
for
statement (sometimes called the "for-each loop" statement).
for
statement (sometimes called the "for-each loop" statement).
for
statement