jodd.util.CollectionUtil Maven / Gradle / Ivy
// Copyright (c) 2003-present, Jodd Team (http://jodd.org)
// All rights reserved.
//
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// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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package jodd.util;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
/**
* Some collection utilities.
*/
public class CollectionUtil {
/**
* Adapt the specified Iterator to the
* Enumeration interface.
*/
public static Enumeration asEnumeration(final Iterator iter) {
return new Enumeration() {
@Override
public boolean hasMoreElements() {
return iter.hasNext();
}
@Override
public E nextElement() {
return iter.next();
}
};
}
/**
* Adapt the specified Enumeration to the Iterator interface.
*/
public static Iterator asIterator(final Enumeration e) {
return new Iterator() {
@Override
public boolean hasNext() {
return e.hasMoreElements();
}
@Override
public E next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
return e.nextElement();
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
}
/**
* Returns a collection containing all elements of the iterator.
*/
public static Collection collectionOf(final Iterator iterator) {
final List list = new ArrayList<>();
while (iterator.hasNext()) {
list.add(iterator.next());
}
return list;
}
/**
* Converts iterator to a stream.
*/
public static Stream streamOf(final Iterator iterator) {
return StreamSupport.stream(((Iterable) () -> iterator).spliterator(), false);
}
/**
* Converts interable to a non-parallel stream.
*/
public static Stream streamOf(final Iterable iterable) {
return StreamSupport.stream(iterable.spliterator(), false);
}
/**
* Wraps an iterator as a stream.
*/
public static Stream parallelStreamOf(final Iterator iterator) {
return StreamSupport.stream(((Iterable) () -> iterator).spliterator(), true);
}
/**
* Wraps an iterator as a stream.
*/
public static Stream parallelStreamOf(final Iterable iterable) {
return StreamSupport.stream(iterable.spliterator(), true);
}
}