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/* Generic definitions */
/* Assertions (useful to generate conditional code) */
/* Current type and class (and size, if applicable) */
/* Value methods */
/* Interfaces (keys) */
/* Interfaces (values) */
/* Abstract implementations (keys) */
/* Abstract implementations (values) */
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/* Static containers (values) */
/* Implementations */
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/* Methods (values) */
/* Methods (keys/values) */
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/*
* Copyright (C) 2002-2016 Sebastiano Vigna
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
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package it.unimi.dsi.fastutil.objects;
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* A class providing static methods and objects that do useful things with
* type-specific iterators.
*
* @see Iterator
*/
public class ObjectBigListIterators {
private ObjectBigListIterators() {
}
/**
* A class returning no elements and a type-specific big list iterator
* interface.
*
*
* This class may be useful to implement your own in case you subclass a
* type-specific iterator.
*/
public static class EmptyBigListIterator extends AbstractObjectBigListIterator implements java.io.Serializable, Cloneable {
private static final long serialVersionUID = -7046029254386353129L;
protected EmptyBigListIterator() {
}
public boolean hasNext() {
return false;
}
public boolean hasPrevious() {
return false;
}
public K next() {
throw new NoSuchElementException();
}
public K previous() {
throw new NoSuchElementException();
}
public long nextIndex() {
return 0;
}
public long previousIndex() {
return -1;
}
public long skip(long n) {
return 0;
};
public long back(long n) {
return 0;
};
public Object clone() {
return EMPTY_BIG_LIST_ITERATOR;
}
private Object readResolve() {
return EMPTY_BIG_LIST_ITERATOR;
}
}
/**
* An empty iterator (immutable). It is serializable and cloneable.
*
*
* The class of this objects represent an abstract empty iterator that can
* iterate as a type-specific (list) iterator.
*/
@SuppressWarnings("rawtypes")
public final static EmptyBigListIterator EMPTY_BIG_LIST_ITERATOR = new EmptyBigListIterator();
/** An iterator returning a single element. */
private static class SingletonBigListIterator extends AbstractObjectBigListIterator {
private final K element;
private int curr;
public SingletonBigListIterator(final K element) {
this.element = element;
}
public boolean hasNext() {
return curr == 0;
}
public boolean hasPrevious() {
return curr == 1;
}
public K next() {
if (!hasNext()) throw new NoSuchElementException();
curr = 1;
return element;
}
public K previous() {
if (!hasPrevious()) throw new NoSuchElementException();
curr = 0;
return element;
}
public long nextIndex() {
return curr;
}
public long previousIndex() {
return curr - 1;
}
}
/**
* Returns an iterator that iterates just over the given element.
*
* @param element
* the only element to be returned by a type-specific list
* iterator.
* @return an iterator that iterates just over element.
*/
public static ObjectBigListIterator singleton(final K element) {
return new SingletonBigListIterator(element);
}
/** An unmodifiable wrapper class for big list iterators. */
public static class UnmodifiableBigListIterator extends AbstractObjectBigListIterator {
final protected ObjectBigListIterator i;
public UnmodifiableBigListIterator(final ObjectBigListIterator i) {
this.i = i;
}
public boolean hasNext() {
return i.hasNext();
}
public boolean hasPrevious() {
return i.hasPrevious();
}
public K next() {
return i.next();
}
public K previous() {
return i.previous();
}
public long nextIndex() {
return i.nextIndex();
}
public long previousIndex() {
return i.previousIndex();
}
}
/**
* Returns an unmodifiable list iterator backed by the specified list
* iterator.
*
* @param i
* the list iterator to be wrapped in an unmodifiable list
* iterator.
* @return an unmodifiable view of the specified list iterator.
*/
public static ObjectBigListIterator unmodifiable(final ObjectBigListIterator i) {
return new UnmodifiableBigListIterator(i);
}
/** A class exposing a list iterator as a big-list iterator.. */
public static class BigListIteratorListIterator extends AbstractObjectBigListIterator {
protected final ObjectListIterator i;
protected BigListIteratorListIterator(final ObjectListIterator i) {
this.i = i;
}
private int intDisplacement(long n) {
if (n < Integer.MIN_VALUE || n > Integer.MAX_VALUE) throw new IndexOutOfBoundsException("This big iterator is restricted to 32-bit displacements");
return (int) n;
}
public void set(K ok) {
i.set(ok);
}
public void add(K ok) {
i.add(ok);
}
public int back(int n) {
return i.back(n);
}
public long back(long n) {
return i.back(intDisplacement(n));
}
public void remove() {
i.remove();
}
public int skip(int n) {
return i.skip(n);
}
public long skip(long n) {
return i.skip(intDisplacement(n));
}
public boolean hasNext() {
return i.hasNext();
}
public boolean hasPrevious() {
return i.hasPrevious();
}
public K next() {
return i.next();
}
public K previous() {
return i.previous();
}
public long nextIndex() {
return i.nextIndex();
}
public long previousIndex() {
return i.previousIndex();
}
}
/**
* Returns a big-list iterator backed by the specified list iterator.
*
* @param i
* the list iterator to adapted to the big-list-iterator
* interface.
* @return a big-list iterator backed by the specified list iterator.
*/
public static ObjectBigListIterator asBigListIterator(final ObjectListIterator i) {
return new BigListIteratorListIterator(i);
}
}