org.neo4j.helpers.collection.IteratorUtil Maven / Gradle / Ivy
/*
* Copyright (c) 2002-2015 "Neo Technology,"
* Network Engine for Objects in Lund AB [http://neotechnology.com]
*
* This file is part of Neo4j.
*
* Neo4j is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see the type of elements in {@code iterator}.
* @param iterator the {@link Iterator} to get elements from.
* @return the first element in the {@code iterator}, or {@code null} if no
* element found.
*/
public static T firstOrNull( Iterator iterator )
{
return iterator.hasNext() ? iterator.next() : null;
}
/**
* Returns the given iterator's first element. If no element is found a
* {@link NoSuchElementException} is thrown.
*
* @param the type of elements in {@code iterator}.
* @param iterator the {@link Iterator} to get elements from.
* @return the first element in the {@code iterator}.
* @throws NoSuchElementException if no element found.
*/
public static T first( Iterator iterator )
{
return assertNotNull( iterator, firstOrNull( iterator ) );
}
/**
* Returns the given iterator's last element or {@code null} if no
* element found.
*
* @param the type of elements in {@code iterator}.
* @param iterator the {@link Iterator} to get elements from.
* @return the last element in the {@code iterator}, or {@code null} if no
* element found.
*/
public static T lastOrNull( Iterator iterator )
{
T result = null;
while ( iterator.hasNext() )
{
result = iterator.next();
}
return result;
}
/**
* Returns the given iterator's last element. If no element is found a
* {@link NoSuchElementException} is thrown.
*
* @param the type of elements in {@code iterator}.
* @param iterator the {@link Iterator} to get elements from.
* @return the last element in the {@code iterator}.
* @throws NoSuchElementException if no element found.
*/
public static T last( Iterator iterator )
{
return assertNotNull( iterator, lastOrNull( iterator ) );
}
/**
* Returns the given iterator's single element or {@code null} if no
* element found. If there is more than one element in the iterator a
* {@link NoSuchElementException} will be thrown.
*
* If the {@code iterator} implements {@link Resource} it will be {@link Resource#close() closed}
* in a {@code finally} block after the single item has been retrieved, or failed to be retrieved.
*
* @param the type of elements in {@code iterator}.
* @param iterator the {@link Iterator} to get elements from.
* @return the single element in {@code iterator}, or {@code null} if no
* element found.
* @throws NoSuchElementException if more than one element was found.
*/
public static T singleOrNull( Iterator iterator )
{
return single( iterator, null );
}
/**
* Returns the given iterator's single element. If there are no elements
* or more than one element in the iterator a {@link NoSuchElementException}
* will be thrown.
*
* If the {@code iterator} implements {@link Resource} it will be {@link Resource#close() closed}
* in a {@code finally} block after the single item has been retrieved, or failed to be retrieved.
*
* @param the type of elements in {@code iterator}.
* @param iterator the {@link Iterator} to get elements from.
* @return the single element in the {@code iterator}.
* @throws NoSuchElementException if there isn't exactly one element.
*/
public static T single( Iterator iterator )
{
return assertNotNull( iterator, singleOrNull( iterator ) );
}
/**
* Returns the iterator's n:th item from the end of the iteration.
* If the iterator has got less than n-1 items in it
* {@link NoSuchElementException} is thrown.
*
* @param the type of elements in {@code iterator}.
* @param iterator the {@link Iterator} to get elements from.
* @param n the n:th item from the end to get.
* @return the iterator's n:th item from the end of the iteration.
* @throws NoSuchElementException if the iterator contains less than n-1 items.
*/
public static T fromEnd( Iterator iterator, int n )
{
return assertNotNull( iterator, fromEndOrNull( iterator, n ) );
}
/**
* Returns the iterator's n:th item from the end of the iteration.
* If the iterator has got less than n-1 items in it {@code null} is returned.
*
* @param the type of elements in {@code iterator}.
* @param iterator the {@link Iterator} to get elements from.
* @param n the n:th item from the end to get.
* @return the iterator's n:th item from the end of the iteration,
* or {@code null} if the iterator doesn't contain that many items.
*/
public static T fromEndOrNull( Iterator iterator, int n )
{
Deque trail = new ArrayDeque<>( n );
while ( iterator.hasNext() )
{
if ( trail.size() > n )
{
trail.removeLast();
}
trail.addFirst( iterator.next() );
}
return trail.size() == n + 1 ? trail.getLast() : null;
}
/**
* Iterates over the full iterators, and checks equality for each item in them. Note that this
* will consume the iterators.
*
* @param first the first iterator
* @param other the other iterator
* @return {@code true} if all items are equal; otherwise
*/
public static boolean iteratorsEqual( Iterator first, Iterator other )
{
while ( true )
{
if ( first.hasNext() && other.hasNext() )
{
if ( !first.next().equals( other.next() ) )
{
return false;
}
}
else
{
return first.hasNext() == other.hasNext();
}
}
}
private static T assertNotNull( Iterator iterator, T result )
{
if ( result == null )
{
throw new NoSuchElementException( "No element found in " + iterator );
}
return result;
}
/**
* Returns the given iterable's first element or {@code null} if no
* element found.
*
* @param the type of elements in {@code iterable}.
* @param iterable the {@link Iterable} to get elements from.
* @return the first element in the {@code iterable}, or {@code null} if no
* element found.
*/
public static T firstOrNull( Iterable iterable )
{
return firstOrNull( iterable.iterator() );
}
/**
* Returns the given iterable's first element. If no element is found a
* {@link NoSuchElementException} is thrown.
*
* @param the type of elements in {@code iterable}.
* @param iterable the {@link Iterable} to get elements from.
* @return the first element in the {@code iterable}.
* @throws NoSuchElementException if no element found.
*/
public static T first( Iterable iterable )
{
return first( iterable.iterator() );
}
/**
* Returns the given iterable's last element or {@code null} if no
* element found.
*
* @param the type of elements in {@code iterable}.
* @param iterable the {@link Iterable} to get elements from.
* @return the last element in the {@code iterable}, or {@code null} if no
* element found.
*/
public static T lastOrNull( Iterable iterable )
{
return lastOrNull( iterable.iterator() );
}
/**
* Returns the given iterable's last element. If no element is found a
* {@link NoSuchElementException} is thrown.
*
* @param the type of elements in {@code iterable}.
* @param iterable the {@link Iterable} to get elements from.
* @return the last element in the {@code iterable}.
* @throws NoSuchElementException if no element found.
*/
public static T last( Iterable iterable )
{
return last( iterable.iterator() );
}
/**
* Returns the given iterable's single element or {@code null} if no
* element found. If there is more than one element in the iterable a
* {@link NoSuchElementException} will be thrown.
*
* If the {@link Iterable#iterator() iterator} created by the {@code iterable} implements {@link Resource}
* it will be {@link Resource#close() closed} in a {@code finally} block after the single item
* has been retrieved, or failed to be retrieved.
*
* @param the type of elements in {@code iterable}.
* @param iterable the {@link Iterable} to get elements from.
* @return the single element in {@code iterable}, or {@code null} if no
* element found.
* @throws NoSuchElementException if more than one element was found.
*/
public static T singleOrNull( Iterable iterable )
{
return singleOrNull( iterable.iterator() );
}
/**
* Returns the given iterable's single element. If there are no elements
* or more than one element in the iterable a {@link NoSuchElementException}
* will be thrown.
*
* If the {@link Iterable#iterator() iterator} created by the {@code iterable} implements {@link Resource}
* it will be {@link Resource#close() closed} in a {@code finally} block after the single item
* has been retrieved, or failed to be retrieved.
*
* @param the type of elements in {@code iterable}.
* @param iterable the {@link Iterable} to get elements from.
* @return the single element in the {@code iterable}.
* @throws NoSuchElementException if there isn't exactly one element.
*/
public static T single( Iterable iterable )
{
return single( iterable.iterator() );
}
/**
* Returns the given iterable's single element or {@code itemIfNone} if no
* element found. If there is more than one element in the iterable a
* {@link NoSuchElementException} will be thrown.
*
* If the {@link Iterable#iterator() iterator} created by the {@code iterable} implements {@link Resource}
* it will be {@link Resource#close() closed} in a {@code finally} block after the single item
* has been retrieved, or failed to be retrieved.
*
* @param the type of elements in {@code iterable}.
* @param iterable the {@link Iterable} to get elements from.
* @param itemIfNone item to use if none is found
* @return the single element in {@code iterable}, or {@code null} if no
* element found.
* @throws NoSuchElementException if more than one element was found.
*/
public static T single( Iterable iterable, T itemIfNone )
{
return single( iterable.iterator(), itemIfNone );
}
/**
* Returns the given iterator's single element or {@code itemIfNone} if no
* element found. If there is more than one element in the iterator a
* {@link NoSuchElementException} will be thrown.
*
* If the {@code iterator} implements {@link Resource} it will be {@link Resource#close() closed}
* in a {@code finally} block after the single item has been retrieved, or failed to be retrieved.
*
* @param the type of elements in {@code iterator}.
* @param iterator the {@link Iterator} to get elements from.
* @param itemIfNone item to use if none is found
* @return the single element in {@code iterator}, or {@code itemIfNone} if no
* element found.
* @throws NoSuchElementException if more than one element was found.
*/
public static T single( Iterator iterator, T itemIfNone )
{
try
{
T result = iterator.hasNext() ? iterator.next() : itemIfNone;
if ( iterator.hasNext() )
{
throw new NoSuchElementException( "More than one element in " + iterator + ". First element is '"
+ result + "' and the second element is '" + iterator.next() + "'" );
}
return result;
}
finally
{
if ( iterator instanceof Resource )
{
((Resource) iterator).close();
}
}
}
/**
* Returns the iterator's n:th item from the end of the iteration.
* If the iterator has got less than n-1 items in it
* {@link NoSuchElementException} is thrown.
*
* @param the type of elements in {@code iterator}.
* @param iterable the {@link Iterable} to get elements from.
* @param n the n:th item from the end to get.
* @return the iterator's n:th item from the end of the iteration.
* @throws NoSuchElementException if the iterator contains less than n-1 items.
*/
public static T fromEnd( Iterable iterable, int n )
{
return fromEnd( iterable.iterator(), n );
}
/**
* Adds all the items in {@code iterator} to {@code collection}.
* @param the type of {@link Collection} to add to items to.
* @param the type of items in the collection and iterator.
* @param iterator the {@link Iterator} to grab the items from.
* @param collection the {@link Collection} to add the items to.
* @return the {@code collection} which was passed in, now filled
* with the items from {@code iterator}.
*/
public static ,T> C addToCollection( Iterator iterator,
C collection )
{
while ( iterator.hasNext() )
{
collection.add( iterator.next() );
}
return collection;
}
/**
* Adds all the items in {@code iterator} to {@code collection}.
* @param the type of {@link Collection} to add to items to.
* @param iterator the {@link Iterator} to grab the items from.
* @param collection the {@link Collection} to add the items to.
* @return the {@code collection} which was passed in, now filled
* with the items from {@code iterator}.
*/
public static > C addToCollection( PrimitiveLongIterator iterator, C collection )
{
while ( iterator.hasNext() )
{
collection.add( iterator.next() );
}
return collection;
}
/**
* Adds all the items in {@code iterator} to {@code collection}.
* @param the type of {@link Collection} to add to items to.
* @param iterator the {@link Iterator} to grab the items from.
* @param collection the {@link Collection} to add the items to.
* @return the {@code collection} which was passed in, now filled
* with the items from {@code iterator}.
*/
public static > C addToCollection( PrimitiveIntIterator iterator, C collection )
{
while ( iterator.hasNext() )
{
collection.add( iterator.next() );
}
return collection;
}
/**
* Adds all the items in {@code iterator} to {@code collection}.
* @param the type of {@link Collection} to add to items to.
* @param the type of items in the collection and iterator.
* @param iterator the {@link Iterator} to grab the items from.
* @param collection the {@link Collection} to add the items to.
* @return the {@code collection} which was passed in, now filled
* with the items from {@code iterator}.
*/
public static ,T> C addToCollectionUnique( Iterator iterator,
C collection )
{
while ( iterator.hasNext() )
{
addUnique( collection, iterator.next() );
}
return collection;
}
private static > void addUnique( C collection, T item )
{
if ( !collection.add( item ) )
{
throw new IllegalStateException( "Encountered an already added item:" + item +
" when adding items uniquely to a collection:" + collection );
}
}
/**
* Adds all the items in {@code iterator} to {@code collection}.
* @param the type of {@link Collection} to add to items to.
* @param the type of items in the collection and iterator.
* @param iterable the {@link Iterator} to grab the items from.
* @param collection the {@link Collection} to add the items to.
* @return the {@code collection} which was passed in, now filled
* with the items from {@code iterator}.
*/
public static ,T> C addToCollection( Iterable iterable,
C collection )
{
return addToCollection( iterable.iterator(), collection );
}
/**
* Adds all the items in {@code iterator} to {@code collection}.
* @param the type of {@link Collection} to add to items to.
* @param the type of items in the collection and iterator.
* @param iterable the {@link Iterator} to grab the items from.
* @param collection the {@link Collection} to add the items to.
* @return the {@code collection} which was passed in, now filled
* with the items from {@code iterator}.
*/
public static ,T> C addToCollectionUnique( Iterable iterable,
C collection )
{
return addToCollectionUnique( iterable.iterator(), collection );
}
/**
* Convenience method for looping over an {@link Iterator}. Converts the
* {@link Iterator} to an {@link Iterable} by wrapping it in an
* {@link Iterable} that returns the {@link Iterator}. It breaks the
* contract of {@link Iterable} in that it returns the supplied iterator
* instance for each call to {@code iterator()} on the returned
* {@link Iterable} instance. This method exists to make it easy to use an
* {@link Iterator} in a for-loop.
*
* @param the type of items in the iterator.
* @param iterator the iterator to expose as an {@link Iterable}.
* @return the supplied iterator posing as an {@link Iterable}.
*/
public static Iterable loop( final Iterator iterator )
{
return new Iterable()
{
@Override
public Iterator iterator()
{
return iterator;
}
};
}
/**
* Exposes {@code iterator} as an {@link Iterable}. It breaks the contract
* of {@link Iterable} in that it returns the supplied iterator instance for
* each call to {@code iterator()} on the returned {@link Iterable}
* instance. This method mostly exists to make it easy to use an
* {@link Iterator} in a for-loop.
*
* @param the type of items in the iterator.
* @param iterator the iterator to expose as an {@link Iterable}.
* @return the supplied iterator posing as an {@link Iterable}.
*/
//@Deprecated * @deprecated use {@link #loop(Iterator) the loop method} instead.
public static Iterable asIterable( final Iterator iterator )
{
return loop( iterator );
}
public static int count( Iterator iterator )
{
return count( iterator, Predicates.alwaysTrue() );
}
/**
* Counts the number of filtered in the {@code iterator} by looping
* through it.
* @param the type of items in the iterator.
* @param iterator the {@link Iterator} to count items in.
* @param filter the filter to test items against
* @return the number of filtered items found in {@code iterator}.
*/
public static int count( Iterator iterator, Predicate filter )
{
int result = 0;
while ( iterator.hasNext() )
{
if ( filter.test( iterator.next() ) )
{
result++;
}
}
return result;
}
/**
* Counts the number of items in the {@code iterator} by looping
* through it.
* @param the type of items in the iterator.
* @param iterable the {@link Iterable} to count items in.
* @return the number of items found in {@code iterable}.
*/
public static int count( Iterable iterable )
{
return count( iterable, Predicates.alwaysTrue() );
}
/**
* Counts the number of items in the {@code iterable} by looping through it.
*
* @param the type of items in the iterator.
* @param iterable the {@link Iterable} to count items in.
* @param filter the filter to apply
* @return the number of items found in {@code iterator}.
*/
public static int count( Iterable iterable, org.neo4j.helpers.Predicate filter )
{
return count( iterable.iterator(), org.neo4j.helpers.Predicates.upgrade( filter ) );
}
/**
* Counts the number of filtered items in the {@code iterable} by looping through it.
*
* @param the type of items in the iterator.
* @param iterable the {@link Iterable} to count items in.
* @param filter the filter to test items against
* @return the number of found in {@code iterable}.
*/
public static int count( Iterable iterable, Predicate filter )
{
return count( iterable.iterator(), filter );
}
/**
* Creates a collection from an iterable.
*
* @param iterable The iterable to create the collection from.
* @param The generic type of both the iterable and the collection.
* @return a collection containing all items from the iterable.
*/
public static Collection asCollection( Iterable iterable )
{
return addToCollection( iterable, new ArrayList() );
}
public static Collection asCollection( Iterator iterable )
{
return addToCollection( iterable, new ArrayList() );
}
public static List asList( Iterator iterator )
{
return addToCollection( iterator, new ArrayList() );
}
public static List asList( Iterable iterator )
{
return addToCollection( iterator, new ArrayList() );
}
public static List asList( PrimitiveLongIterator iterator )
{
List out = new ArrayList<>();
while(iterator.hasNext())
{
out.add(iterator.next());
}
return out;
}
public static List asList( PrimitiveIntIterator iterator )
{
List out = new ArrayList<>();
while(iterator.hasNext())
{
out.add(iterator.next());
}
return out;
}
public static Map asMap( Iterable> pairs )
{
Map map = new HashMap<>();
for (Pair pair: pairs) {
map.put(pair.first(), pair.other());
}
return map;
}
/**
* Creates a {@link Set} from an {@link Iterable}.
*
* @param iterable The items to create the set from.
* @param The generic type of items.
* @return a set containing all items from the {@link Iterable}.
*/
public static Set asSet( Iterable iterable )
{
return addToCollection( iterable, new HashSet() );
}
public static Set asSet( Iterator iterator )
{
return addToCollection( iterator, new HashSet() );
}
/**
* Creates a {@link Set} from an {@link Iterable}.
*
* @param iterable The items to create the set from.
* @param The generic type of items.
* @return a set containing all items from the {@link Iterable}.
*/
public static Set asUniqueSet( Iterable iterable )
{
return addToCollectionUnique( iterable, new HashSet() );
}
/**
* Creates a {@link Set} from an array of items.
*
* @param items the items to add to the set.
* @param the type of the items
* @return the {@link Set} containing the items.
*/
@SafeVarargs
public static Set asSet( T... items )
{
return new HashSet<>( Arrays.asList( items ) );
}
public static Set emptySetOf( @SuppressWarnings("unused"/*just used as a type marker*/) Class type )
{
return Collections.emptySet();
}
public static List emptyListOf( @SuppressWarnings("unused"/*just used as a type marker*/) Class type )
{
return Collections.emptyList();
}
/**
* Alias for asSet()
*
* @param items the items to add to the set.
* @param the type of the items
* @return the {@link Set} containing the items.
*/
@SafeVarargs
public static Set set( T... items)
{
return asSet(items);
}
/**
* Creates a {@link Set} from an array of items.
*
* @param items the items to add to the set.
* @param the type of the items
* @return the {@link Set} containing the items.
*/
@SafeVarargs
public static Set asUniqueSet( T... items )
{
HashSet set = new HashSet<>();
for ( T item : items )
{
addUnique( set, item );
}
return set;
}
/**
* Creates a {@link Set} from an array of items.
*
* @param items the items to add to the set.
* @param the type of the items
* @return the {@link Set} containing the items.
*/
public static Set asUniqueSet( Iterator items )
{
HashSet set = new HashSet<>();
while( items.hasNext() )
{
addUnique( set, items.next() );
}
return set;
}
/**
* Function for converting Enum to String
*/
@SuppressWarnings( "rawtypes" )
public final static Function ENUM_NAME = new Function()
{
@Override
public String apply( Enum from )
{
return from.name();
}
};
/**
* Converts an {@link Iterable} of enums to {@link Set} of their names.
*
* @param enums the enums to convert.
* @return the set of enum names
*/
@SuppressWarnings( "rawtypes" )
public static Set asEnumNameSet( Iterable enums )
{
return asSet( map( ENUM_NAME, enums ) );
}
/**
* Converts an enum class to to {@link Set} of the names of all valid enum values
*
* @param clazz enum class
* @param enum type bound
* @return the set of enum names
*/
public static > Set asEnumNameSet( Class clazz)
{
return asSet( map( ENUM_NAME, allOf( clazz ) ) );
}
/**
* Creates an {@link Iterable} for iterating over the lines of a text file.
* @param file the file to get the lines for.
* @param encoding the encoding of the file
* @return an {@link Iterable} for iterating over the lines of a text file.
*/
public static ClosableIterable asIterable( final File file, final String encoding )
{
return new ClosableIterable()
{
private ClosableIterator mostRecentIterator;
@Override
public Iterator iterator()
{
try
{
if ( mostRecentIterator != null )
{
mostRecentIterator.close();
}
mostRecentIterator = asIterator( file, encoding );
return mostRecentIterator;
}
catch ( IOException e )
{
throw new RuntimeException( e );
}
}
@Override
public void close()
{
if ( mostRecentIterator != null )
{
mostRecentIterator.close();
}
}
};
}
/**
* Creates an {@link Iterator} for iterating over the lines of a text file.
* The opened file is closed if an exception occurs during reading or when
* the files has been read through all the way.
* @param file the file to get the lines for.
* @param encoding to be used for reading the file
* @return an {@link Iterator} for iterating over the lines of a text file.
* @throws IOException from underlying I/O operations
*/
public static ClosableIterator asIterator( File file, String encoding ) throws IOException
{
return new LinesOfFileIterator( file, encoding );
}
public static Iterable asIterable( final long... array )
{
return new Iterable()
{
@Override
public Iterator iterator()
{
return asIterator( array );
}
};
}
@SafeVarargs
public static Iterable asIterable( final T... array )
{
return new Iterable()
{
@Override
public Iterator iterator()
{
return IteratorUtil.iterator( array );
}
};
}
public static Iterator asIterator( final long... array )
{
return new PrefetchingIterator()
{
private int index;
@Override
protected Long fetchNextOrNull()
{
try
{
return index < array.length ? array[index] : null;
}
finally
{
index++;
}
}
};
}
@SafeVarargs
public static Iterator asIterator( final int maxItems, final T... array )
{
return new PrefetchingIterator()
{
private int index;
@Override
protected T fetchNextOrNull()
{
try
{
return index < array.length && index < maxItems ? array[index] : null;
}
finally
{
index++;
}
}
};
}
public static Iterator iterator( final T item )
{
if ( item == null )
{
return emptyIterator();
}
return new Iterator()
{
T myItem = item;
@Override
public boolean hasNext()
{
return myItem != null;
}
@Override
public T next()
{
if ( !hasNext() )
{
throw new NoSuchElementException();
}
T toReturn = myItem;
myItem = null;
return toReturn;
}
@Override
public void remove()
{
throw new UnsupportedOperationException();
}
};
}
@SafeVarargs
public static Iterator iterator( T ... items )
{
return asIterator( items.length, items );
}
@SafeVarargs
public static Iterator iterator( int maxItems, T ... items )
{
return asIterator( maxItems, items );
}
@SuppressWarnings( "rawtypes" )
private static final ResourceIterator EMPTY_ITERATOR = new ResourceIterator()
{
@Override
public boolean hasNext()
{
return false;
}
@Override
public Object next()
{
throw new NoSuchElementException();
}
@Override
public void remove()
{
throw new UnsupportedOperationException();
}
@Override
public void close()
{
// do nothing
}
};
@SuppressWarnings( "unchecked" )
public static ResourceIterator emptyIterator()
{
return EMPTY_ITERATOR;
}
public static boolean contains( Iterator iterator, T item )
{
try
{
for ( T element : loop( iterator ) )
{
if ( item == null ? element == null : item.equals( element ) )
{
return true;
}
}
return false;
}
finally
{
if ( iterator instanceof ResourceIterator )
{
((ResourceIterator) iterator).close();
}
}
}
public static Iterable cloned( Iterable items, final Class itemClass )
{
return Iterables.map( new Function()
{
@Override
public T apply( T from )
{
return itemClass.cast( from.clone() );
}
}, items );
}
public static ResourceIterator asResourceIterator( final Iterator iterator )
{
return new WrappingResourceIterator<>( iterator );
}
@SuppressWarnings("UnusedDeclaration"/*Useful when debugging in tests, but not used outside of debugging sessions*/)
public static Iterator toJavaIterator( final PrimitiveLongIterator primIterator )
{
return new Iterator()
{
@Override
public boolean hasNext()
{
return primIterator.hasNext();
}
@Override
public Long next()
{
return primIterator.next();
}
@Override
public void remove()
{
throw new UnsupportedOperationException( );
}
};
}
public static List primitivesList( PrimitiveLongIterator iterator )
{
ArrayList result = new ArrayList<>();
while ( iterator.hasNext() )
{
result.add( iterator.next() );
}
return result;
}
public static Set asSet( PrimitiveLongIterator iterator )
{
return internalAsSet( iterator, false );
}
private static Set internalAsSet( PrimitiveLongIterator iterator, boolean allowDuplicates )
{
Set set = new HashSet<>();
while ( iterator.hasNext() )
{
long value = iterator.next();
if ( !set.add( value ) && !allowDuplicates )
{
throw new IllegalStateException( "Duplicates found. Tried to add " + value + " to " + set );
}
}
return set;
}
public static Set asSet( PrimitiveIntIterator iterator )
{
Set set = new HashSet<>();
while ( iterator.hasNext() )
{
set.add( iterator.next() );
}
return set;
}
/**
* Creates a {@link Set} from an array of iterator.
*
* @param iterator the iterator to add to the set.
* @return the {@link Set} containing the iterator.
*/
public static Set asUniqueSet( PrimitiveLongIterator iterator )
{
HashSet set = new HashSet<>();
while ( iterator.hasNext() )
{
addUnique( set, iterator.next() );
}
return set;
}
public static PrimitiveLongResourceIterator resourceIterator( final PrimitiveLongIterator iterator,
final Resource resource )
{
return new PrimitiveLongResourceIterator()
{
@Override
public void close()
{
if ( resource != null )
{
resource.close();
}
}
@Override
public long next()
{
return iterator.next();
}
@Override
public boolean hasNext()
{
return iterator.hasNext();
}
};
}
public static ResourceIterator resourceIterator( final Iterator iterator, final Resource resource )
{
return new PrefetchingResourceIterator()
{
@Override
public void close()
{
resource.close();
}
@Override
protected T fetchNextOrNull()
{
return iterator.hasNext() ? iterator.next() : null;
}
};
}
public static ResourceIterable resourceIterable( final Iterable iterable )
{
return new ResourceIterable()
{
@Override
public ResourceIterator iterator()
{
return resourceIterator( iterable.iterator(), Resource.EMPTY );
}
};
}
@SafeVarargs
public static T[] array( T... items )
{
return items;
}
}
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