Package net.cscott.jutil

Class Default

java.lang.Object

net.cscott.jutil.Default

public abstract class Default
extends Object

Default contains one-off or 'standard, no-frills' implementations of simple Iterators, Collections, and Comparators.

Author:

C. Scott Ananian <cananian@alumni.princeton.edu>

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Default.PairList<A,B>	Deprecated. Use Pair, an immutable record whose Pair.left() and Pair.right() replace the methods of the same name.

Field Summary

Fields

Modifier and Type	Field	Description
static final Comparator	comparator	Deprecated. Use Comparator.nullsFirst(Comparator.naturalOrder()), which this is.
static final SortedMap	EMPTY_MAP	Deprecated. Use Collections.emptySortedMap(), or Collections.emptyMap() when the map need not be a SortedMap.
static final MultiMap	EMPTY_MULTIMAP	Deprecated. Use EMPTY_MULTIMAP(), which is parameterized.
static final SortedSet	EMPTY_SET	Deprecated. Use Collections.emptySortedSet(), or Collections.emptySet() when the set need not be a SortedSet.
static final Iterator	nullIterator	Deprecated. Use Collections.emptyIterator().

Constructor Summary

Constructors

Constructor	Description
Default()

Method Summary

Modifier and Type	Method	Description
static final <T extends Comparable<T>> Comparator<T>	comparator()	Deprecated. Use Comparator.nullsFirst(Comparator.naturalOrder()), which this returns.
static final <E> List<E>	EMPTY_LIST()	Deprecated. Use Collections.emptyList(), which this returns.
static final <K, V> SortedMap<K,V>	EMPTY_MAP()	Deprecated. Use Collections.emptySortedMap(), or Collections.emptyMap() when the map need not be a SortedMap.
static final <K, V> MultiMap<K,V>	EMPTY_MULTIMAP()	An empty multi-map, parameterized to play nicely with Java's type system.
static final <E> SortedSet<E>	EMPTY_SET()	Deprecated. Use Collections.emptySortedSet(), or Collections.emptySet() when the set need not be a SortedSet.
static <K, V> Map.Entry<K,V>	entry(K key, V value)	Deprecated. Use AbstractMap.SimpleImmutableEntry, which this method now returns, or Map.entry(Object,Object), which does not permit nulls.
static final <E> Iterator<E>	nullIterator()	Deprecated. Use Collections.emptyIterator().
static <A, B> Default.PairList<A,B>	pair(A left, B right)	Deprecated. Use Pair, an immutable record: new Pair<>(left, right).
static final <E> Iterator<E>	singletonIterator(E o)	An Iterator over a singleton set.
static <A> Collection<A>	unmodifiableCollection(Collection<? extends A> cc)	Improved unmodifiableCollection() class that helps w/ covariant subtyping.
static final <E> Iterator<E>	unmodifiableIterator(Iterator<? extends E> i)	An unmodifiable version of the given iterator: its remove() method throws UnsupportedOperationException.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

comparator

@Deprecated(since="2.0")
public static final Comparator comparator

Deprecated.

Use Comparator.nullsFirst(Comparator.naturalOrder()), which this is. Plain Comparator.naturalOrder() is not a replacement: it throws NullPointerException when it compares null.

A Comparator for objects that implement Comparable (checked dynamically at run-time). null is less than everything else.

nullIterator

@Deprecated(since="2.0")
public static final Iterator nullIterator

Deprecated.

Use Collections.emptyIterator(). Unlike this iterator, the remove() method of Collections.emptyIterator() throws IllegalStateException, not UnsupportedOperationException.

An Iterator over the empty set.

EMPTY_SET

@Deprecated(since="1.3")
public static final SortedSet EMPTY_SET

Deprecated.

Use Collections.emptySortedSet(), or Collections.emptySet() when the set need not be a SortedSet.

An empty set.

Since:

1.2

EMPTY_MAP

@Deprecated(since="1.3")
public static final SortedMap EMPTY_MAP

Deprecated.

Use Collections.emptySortedMap(), or Collections.emptyMap() when the map need not be a SortedMap.

An empty map. Missing from Collections in Java 1.2.

EMPTY_MULTIMAP

@Deprecated(since="2.0")
public static final MultiMap EMPTY_MULTIMAP

Deprecated.

Use EMPTY_MULTIMAP(), which is parameterized.

An empty multi-map.

Constructor Details

Default

public Default()

Method Details

comparator

@Deprecated(since="2.0")
public static final <T extends Comparable<T>>
Comparator<T> comparator()

Deprecated.

Use Comparator.nullsFirst(Comparator.naturalOrder()), which this returns. Plain Comparator.naturalOrder() is not a replacement: it throws NullPointerException when it compares null.

A Comparator for objects that implement Comparable (checked dynamically at run-time). null is less than everything else. This version is parameterized to play nicely with Java's type system.

Since:

1.2

nullIterator

@Deprecated(since="2.0")
public static final <E> Iterator<E> nullIterator()

Deprecated.

Use Collections.emptyIterator(). Unlike this iterator, the remove() method of Collections.emptyIterator() throws IllegalStateException, not UnsupportedOperationException.

An Iterator over the empty set, parameterized to play nicely with Java's type system.

singletonIterator

public static final <E> Iterator<E> singletonIterator(E o)

An Iterator over a singleton set.

unmodifiableIterator

public static final <E> Iterator<E> unmodifiableIterator(Iterator<? extends E> i)

An unmodifiable version of the given iterator: its remove() method throws UnsupportedOperationException.

EMPTY_SET

@Deprecated(since="1.3")
public static final <E> SortedSet<E> EMPTY_SET()

Deprecated.

Use Collections.emptySortedSet(), or Collections.emptySet() when the set need not be a SortedSet.

An empty set; the parameterized version. Plays nicely with Java's type system.

EMPTY_LIST

@Deprecated(since="1.3")
public static final <E> List<E> EMPTY_LIST()

Deprecated.

Use Collections.emptyList(), which this returns.

An empty list. The parameterized version. Made necessary by limitations in GJ's type system.

EMPTY_MAP

@Deprecated(since="1.3")
public static final <K,
V> SortedMap<K,V> EMPTY_MAP()

Deprecated.

Use Collections.emptySortedMap(), or Collections.emptyMap() when the map need not be a SortedMap.

An empty map, parameterized to play nicely with Java's type system.

Since:

1.2

EMPTY_MULTIMAP

public static final <K,
V> MultiMap<K,V> EMPTY_MULTIMAP()

An empty multi-map, parameterized to play nicely with Java's type system.

Since:

1.2

unmodifiableCollection

public static <A> Collection<A> unmodifiableCollection(Collection<? extends A> cc)

Improved unmodifiableCollection() class that helps w/ covariant subtyping.

pair

@Deprecated(since="2.0")
public static <A,
B> Default.PairList<A,B> pair(A left,
 B right)

Deprecated.

Use Pair, an immutable record: new Pair<>(left, right). For an immutable list, use List.of(Object,Object), which does not permit nulls.

A pair constructor method. Pairs implement hashCode() and equals() "properly" so they can be used as keys in hashtables and etc. They are implemented as mutable lists of fixed size 2.

entry

@Deprecated(since="2.0")
public static <K,
V> Map.Entry<K,V> entry(K key,
 V value)

Deprecated.

Use AbstractMap.SimpleImmutableEntry, which this method now returns, or Map.entry(Object,Object), which does not permit nulls.

A pair constructor method more appropriate for Set views of Maps and MultiMaps. The returned object is an instance of Map.Entry; the only (real) difference from the pairs returned by Default.pair() is the definition of hashCode(), which corresponds to Map.Entry (being key.hashCode() ^ value.hashCode() ) rather than List (which would be 31*(31+key.hashCode())+value.hashCode() ). This is an annoying distinction; I wish the JDK API authors had made these consistent. The Map.Entry returned is immutable.