Example usage for java.util Iterator Iterator

List of usage examples for java.util Iterator Iterator

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Introduction

In this page you can find the example usage for java.util Iterator Iterator.

Prototype

Iterator

Source Link

Usage

From source file:Main.java

/**
 * Returns an iterator over the values referenced by the elements of {@code
 * iterable}.//from  w  w  w.jav  a  2s . c o m
 *
 * @param trim true to remove reference objects from the iterable after
 *     their referenced values have been cleared.
 */
public static <T> Iterable<T> dereferenceIterable(final Iterable<? extends Reference<T>> iterable,
        final boolean trim) {
    return new Iterable<T>() {
        public Iterator<T> iterator() {
            return new Iterator<T>() {
                private final Iterator<? extends Reference<T>> delegate = iterable.iterator();
                private boolean removeIsOkay;
                private T next;

                private void computeNext() {
                    removeIsOkay = false;
                    while (next == null && delegate.hasNext()) {
                        next = delegate.next().get();
                        if (trim && next == null) {
                            delegate.remove();
                        }
                    }
                }

                @Override
                public boolean hasNext() {
                    computeNext();
                    return next != null;
                }

                @Override
                public T next() {
                    if (!hasNext()) {
                        throw new IllegalStateException();
                    }
                    T result = next;
                    removeIsOkay = true;
                    next = null;
                    return result;
                }

                public void remove() {
                    if (!removeIsOkay) {
                        throw new IllegalStateException();
                    }
                    delegate.remove();
                }
            };
        }
    };
}

From source file:Main.java

/**
 * Zips the specified stream with its indices.
 *//*from   w  w w .j  a va 2  s . c o  m*/
public static <T> Stream<Map.Entry<Integer, T>> zipWithIndex(Stream<? extends T> stream, int startIndex) {
    return iterate(new Iterator<Map.Entry<Integer, T>>() {
        private final Iterator<? extends T> streamIterator = stream.iterator();
        private int index = startIndex;

        @Override
        public boolean hasNext() {
            return streamIterator.hasNext();
        }

        @Override
        public Map.Entry<Integer, T> next() {
            return new AbstractMap.SimpleImmutableEntry<>(index++, streamIterator.next());
        }
    });
}

From source file:Main.java

static Iterable<JavaSourceFromString> getJavaSourceFromString(String code) {
    final JavaSourceFromString jsfs = new JavaSourceFromString("code", code);
    return new Iterable<JavaSourceFromString>() {
        public Iterator<JavaSourceFromString> iterator() {
            return new Iterator<JavaSourceFromString>() {
                boolean isNext = true;

                public boolean hasNext() {
                    return isNext;
                }/*from ww w  .  jav  a2 s.  c  o  m*/

                public JavaSourceFromString next() {
                    if (!isNext)
                        throw new NoSuchElementException();
                    isNext = false;
                    return jsfs;
                }

                public void remove() {
                    throw new UnsupportedOperationException();
                }
            };
        }
    };
}

From source file:CompileString.java

static Iterable<JavaSourceFromString> getJavaSourceFromString(String code) {
    final JavaSourceFromString jsfs;
    jsfs = new JavaSourceFromString("code", code);
    return new Iterable<JavaSourceFromString>() {
        public Iterator<JavaSourceFromString> iterator() {
            return new Iterator<JavaSourceFromString>() {
                boolean isNext = true;

                public boolean hasNext() {
                    return isNext;
                }/*from  w w  w . ja  v a2 s.  c o  m*/

                public JavaSourceFromString next() {
                    if (!isNext)
                        throw new NoSuchElementException();
                    isNext = false;
                    return jsfs;
                }

                public void remove() {
                    throw new UnsupportedOperationException();
                }
            };
        }
    };
}

From source file:Main.java

public static Iterable<Node> iterateOverChildren(final Node element) {
    return new Iterable<Node>() {

        NodeList childNodes = element.getChildNodes();
        int itemIndex = 0;
        int nItems = childNodes.getLength();

        @Override//  ww  w .j a va 2  s . c o  m
        public Iterator<Node> iterator() {
            return new Iterator<Node>() {

                @Override
                public void remove() {
                    throw new UnsupportedOperationException();
                }

                @Override
                public Node next() {
                    return childNodes.item(itemIndex++);
                }

                @Override
                public boolean hasNext() {
                    return itemIndex < nItems;
                }
            };
        }
    };
}

From source file:Main.java

public static Collection<Node> createNodeCollection(final NodeList nodeList) {
    // http://www.java2s.com/Code/Java/XML/WrapNodeListtoCollection.htm
    // Written by Tomer Gabel under the Apache License Version 2.0
    return new Collection<Node>() {
        @Override/*from  w  w  w.  ja v a  2s. c  om*/
        public int size() {
            return nodeList.getLength();
        }

        @Override
        public boolean isEmpty() {
            return nodeList.getLength() > 0;
        }

        @Override
        public boolean contains(final Object o) {
            if (o == null || !(o instanceof Node))
                return false;
            for (int i = 0; i < nodeList.getLength(); ++i)
                if (o == nodeList.item(i))
                    return true;
            return false;
        }

        @Override
        public Iterator<Node> iterator() {
            return new Iterator<Node>() {
                private int index = 0;

                @Override
                public boolean hasNext() {
                    return nodeList.getLength() > this.index;
                }

                @Override
                public Node next() {
                    if (this.index >= nodeList.getLength())
                        throw new NoSuchElementException();
                    return nodeList.item(this.index++);
                }

                @Override
                public void remove() {
                    throw new UnsupportedOperationException();
                }
            };
        }

        @Override
        public Object[] toArray() {
            final Node[] array = new Node[nodeList.getLength()];
            for (int i = 0; i < array.length; ++i)
                array[i] = nodeList.item(i);
            return array;
        }

        @Override
        @SuppressWarnings({ "unchecked" })
        public <T> T[] toArray(final T[] a) throws ArrayStoreException {
            if (!a.getClass().getComponentType().isAssignableFrom(Node.class))
                throw new ArrayStoreException(
                        a.getClass().getComponentType().getName() + " is not the same or a supertype of Node");

            if (a.length >= nodeList.getLength()) {
                for (int i = 0; i < nodeList.getLength(); ++i)
                    a[i] = (T) nodeList.item(i);
                if (a.length > nodeList.getLength())
                    a[nodeList.getLength()] = null;
                return a;
            }

            return (T[]) toArray();
        }

        @Override
        public boolean add(final Node node) {
            throw new UnsupportedOperationException();
        }

        @Override
        public boolean remove(final Object o) {
            throw new UnsupportedOperationException();
        }

        @Override
        public boolean containsAll(final Collection<?> c) {
            for (final Object o : c)
                if (!this.contains(o))
                    return false;
            return true;
        }

        @Override
        public boolean addAll(final Collection<? extends Node> c) {
            throw new UnsupportedOperationException();
        }

        @Override
        public boolean removeAll(final Collection<?> c) {
            throw new UnsupportedOperationException();
        }

        @Override
        public boolean retainAll(final Collection<?> c) {
            throw new UnsupportedOperationException();
        }

        @Override
        public void clear() {
            throw new UnsupportedOperationException();
        }
    };
}

From source file:Util.java

/**
 * Renvoie les lments enfants (uniquement de type ELEMENT)
 * //  www .j  a v a 2s.  c  om
 * @param e
 * @return
 */
public static Iterable<Element> getChildElements(final Element e) {
    return new Iterable<Element>() {
        public Iterator<Element> iterator() {
            final NodeList list = e.getChildNodes();
            int i = 0;
            for (; i < list.getLength(); i++) {
                if (list.item(i).getNodeType() == Node.ELEMENT_NODE)
                    break;
            }
            final int init = i;
            return new Iterator<Element>() {
                int cur = init;

                public void remove() {
                    throw new UnsupportedOperationException();
                }

                public Element next() {
                    Element item = (Element) list.item(cur);
                    for (cur++; cur < list.getLength(); cur++) {
                        if (list.item(cur).getNodeType() == Node.ELEMENT_NODE)
                            break;
                    }
                    return item;
                }

                public boolean hasNext() {
                    return cur < list.getLength();
                }

            };
        }
    };
}

From source file:IteratorUtils.java

public static Iterator oneElementUnmodifiableIterator(final Object elem) {
    return new Iterator() {
        boolean shot = false;

        public boolean hasNext() {
            return (!shot);
        }//ww  w .j  a  va  2s .  co m

        public Object next() {
            if (shot)
                throw new NoSuchElementException();
            else {
                shot = true;
                return elem;
            }
        }

        public void remove() {
            throw new UnsupportedOperationException("remove() not supported.");
        }
    };
}

From source file:Main.java

/**
 * Convenient method to chain iterables together.
 * @param iterables to chain/*from ww w  . j  a va  2s .c om*/
 * @return chained iterator
 */
public static <T> Iterator chain(Iterator<T>... iterables) {
    List<Iterator<T>> iterableList = Arrays.asList(iterables);
    return new Iterator<T>() {
        @Override
        public boolean hasNext() {
            return iterableList.stream().anyMatch(Iterator::hasNext);
        }

        @Override
        public T next() {
            return iterableList.stream().filter(Iterator::hasNext).findFirst().map(Iterator::next).orElse(null);
        }
    };
}

From source file:CollectionUtilities.java

public static Iterator iteratorUnion(final Iterator[] iterators) {
    return new Iterator() {
        private int iteratorIndex = 0;
        private Iterator current = iterators.length > 0 ? iterators[0] : null;

        public boolean hasNext() {
            for (;;) {
                if (current == null) {
                    return false;
                }/*from w w w . ja va 2  s .  co m*/
                if (current.hasNext()) {
                    return true;
                }
                iteratorIndex++;
                current = iteratorIndex >= iterators.length ? null : iterators[iteratorIndex];
            }
        }

        public Object next() {
            for (;;) {
                if (this.current == null) {
                    throw new NoSuchElementException();
                }
                try {
                    return this.current.next();
                } catch (NoSuchElementException nse) {
                    this.iteratorIndex++;
                    this.current = this.iteratorIndex >= iterators.length ? null
                            : iterators[this.iteratorIndex];
                }
            }
        }

        public void remove() {
            if (this.current == null) {
                throw new NoSuchElementException();
            }
            this.current.remove();
        }
    };
}