org.openjdk.jmc.common.collection

Class IteratorToolkit

java.lang.Object

org.openjdk.jmc.common.collection.IteratorToolkit

public class IteratorToolkit
extends java.lang.Object

Various methods that work with iterators.

Constructor Summary

Constructors

Constructor and Description
IteratorToolkit()

Method Summary

Modifier and Type	Method and Description
static <T> java.util.Iterator<T>	filter(java.util.Iterator<T> itr, java.util.function.Predicate<? super T> filter) Wrap an iterator in a new iterator that filters out values based on a predicate.
static <T> java.util.Iterator<T>	of(T[] elements) Iterator that iterates over an array.
(package private) static <T> java.util.Iterator<T>	of(T[] elements, int offset, int len) Iterator that iterates over a part of an array.
static <T> java.util.Iterator<T>	skipNulls(java.util.Iterator<T> itr) Wrap an iterator in a new iterator that skips all null values.
static <T> java.util.List<T>	toList(java.util.Iterator<T> itr, int sizeHint) Place all elements of an iterator in a list.

Methods inherited from class java.lang.Object

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

Constructor Detail

IteratorToolkit

public IteratorToolkit()

Method Detail

toList

public static <T> java.util.List<T> toList(java.util.Iterator<T> itr,
                                           int sizeHint)

Place all elements of an iterator in a list.

Type Parameters:

T - input iterator type

Parameters:

itr - iterator

sizeHint - a hint of how many elements there are

Returns:

a new list with all elements from the iterator

skipNulls

public static <T> java.util.Iterator<T> skipNulls(java.util.Iterator<T> itr)

Wrap an iterator in a new iterator that skips all null values.

Type Parameters:

T - input iterator type

Parameters:

itr - input iterator that may produce null values

Returns:

a new iterator that will never produce null values

filter

public static <T> java.util.Iterator<T> filter(java.util.Iterator<T> itr,
                                               java.util.function.Predicate<? super T> filter)

Wrap an iterator in a new iterator that filters out values based on a predicate.

Type Parameters:

T - input iterator type

Parameters:

itr - input iterator

filter - filter predicate

Returns:

a new iterator that only contains values where the filter evaluates to true

of

public static <T> java.util.Iterator<T> of(T[] elements)

Iterator that iterates over an array. Hopefully faster than Arrays.asList(...).iterator() since there are no concurrency checks.

Type Parameters:

T - input iterator type

Parameters:

elements - elements to iterate over

Returns:

an iterator

of

static <T> java.util.Iterator<T> of(T[] elements,
                                    int offset,
                                    int len)

Iterator that iterates over a part of an array. Hopefully faster than Arrays.asList(...).iterator() since there are no concurrency checks.

Type Parameters:

T - input iterator type

Parameters:

elements - elements to iterate over

offset - array index to start the iterator on

len - number of elements to iterate over

Returns:

an iterator