/*******************************************************************************
* Companion code for the book "Introduction to Software Design with Java",
* 2nd edition by Martin P. Robillard.
*
* Copyright (C) 2022 by Martin P. Robillard
*
* This code is licensed under a Creative Commons
* Attribution-NonCommercial-NoDerivatives 4.0 International License.
*
* See http://creativecommons.org/licenses/by-nc-nd/4.0/
*
*******************************************************************************/
package e2.chapter8;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
/**
* A card source composed of other card sources.
*/
public class CompositeCardSource implements CardSource, Iterable<CardSource>
{
private final List<CardSource> aElements;
@Override
public Iterator<CardSource> iterator()
{
return aElements.iterator();
}
public CompositeCardSource(CardSource... pSources)
{
aElements = Arrays.asList(pSources);
}
@Override
public Card draw()
{
assert !isEmpty();
for( CardSource source : aElements )
{
if( !source.isEmpty() )
{
return source.draw();
}
}
assert false;
return null;
}
@Override
public boolean isEmpty()
{
for( CardSource source : aElements )
{
if( !source.isEmpty() )
{ return false; }
}
return true;
}
@Override
public void accept(CardSourceVisitor pVisitor)
{
pVisitor.visitCompositeCardSource(this);
}
}for statement (sometimes called the "for-each loop" statement).for statement (sometimes called the "for-each loop" statement).for statementSerializable and implements RandomAccess.
Serializable and implements RandomAccess.
The returned list implements the optional Collection methods, except
those that would change the size of the returned list. Those methods leave
the list unchanged and throw UnsupportedOperationException.
Collection.toArray().
This method provides a way to wrap an existing array:
Integer[] numbers = ...
...
List<Integer> values = Arrays.asList(numbers);
This method also provides a convenient way to create a fixed-size list initialized to contain several elements:
List<String> stooges = Arrays.asList("Larry", "Moe", "Curly");
The list returned by this method is modifiable.
To create an unmodifiable list, use
Collections.unmodifiableList
or Unmodifiable Lists.
T - the class of the objects in the arraya - the array by which the list will be backedNullPointerException - if the specified array is nullThe methods in this class all throw a NullPointerException,
if the specified array reference is null, except where noted.
The documentation for the methods contained in this class includes
brief descriptions of the implementations. 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(Object[]) does not have to be
a MergeSort, but it does have to be stable.)
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.
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.