it.unimi.dsi.fastutil.floats.FloatBigListIterators Maven / Gradle / Ivy
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/*
* Copyright (C) 2002-2017 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
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package it.unimi.dsi.fastutil.floats;
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 final class FloatBigListIterators {
private FloatBigListIterators() {
}
/**
* 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 implements FloatBigListIterator, java.io.Serializable, Cloneable {
private static final long serialVersionUID = -7046029254386353129L;
protected EmptyBigListIterator() {
}
@Override
public boolean hasNext() {
return false;
}
@Override
public boolean hasPrevious() {
return false;
}
@Override
public float nextFloat() {
throw new NoSuchElementException();
}
@Override
public float previousFloat() {
throw new NoSuchElementException();
}
@Override
public long nextIndex() {
return 0;
}
@Override
public long previousIndex() {
return -1;
}
@Override
public long skip(long n) {
return 0;
};
@Override
public long back(long n) {
return 0;
};
@Override
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.
*/
public static final EmptyBigListIterator EMPTY_BIG_LIST_ITERATOR = new EmptyBigListIterator();
/** An iterator returning a single element. */
private static class SingletonBigListIterator implements FloatBigListIterator {
private final float element;
private int curr;
public SingletonBigListIterator(final float element) {
this.element = element;
}
@Override
public boolean hasNext() {
return curr == 0;
}
@Override
public boolean hasPrevious() {
return curr == 1;
}
@Override
public float nextFloat() {
if (!hasNext())
throw new NoSuchElementException();
curr = 1;
return element;
}
@Override
public float previousFloat() {
if (!hasPrevious())
throw new NoSuchElementException();
curr = 0;
return element;
}
@Override
public long nextIndex() {
return curr;
}
@Override
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 {@code element}.
*/
public static FloatBigListIterator singleton(final float element) {
return new SingletonBigListIterator(element);
}
/** An unmodifiable wrapper class for big list iterators. */
public static class UnmodifiableBigListIterator implements FloatBigListIterator {
protected final FloatBigListIterator i;
public UnmodifiableBigListIterator(final FloatBigListIterator i) {
this.i = i;
}
@Override
public boolean hasNext() {
return i.hasNext();
}
@Override
public boolean hasPrevious() {
return i.hasPrevious();
}
@Override
public float nextFloat() {
return i.nextFloat();
}
@Override
public float previousFloat() {
return i.previousFloat();
}
@Override
public long nextIndex() {
return i.nextIndex();
}
@Override
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 FloatBigListIterator unmodifiable(final FloatBigListIterator i) {
return new UnmodifiableBigListIterator(i);
}
/** A class exposing a list iterator as a big-list iterator.. */
public static class BigListIteratorListIterator implements FloatBigListIterator {
protected final FloatListIterator i;
protected BigListIteratorListIterator(final FloatListIterator 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;
}
@Override
public void set(float ok) {
i.set(ok);
}
@Override
public void add(float ok) {
i.add(ok);
}
@Override
public int back(int n) {
return i.back(n);
}
@Override
public long back(long n) {
return i.back(intDisplacement(n));
}
@Override
public void remove() {
i.remove();
}
@Override
public int skip(int n) {
return i.skip(n);
}
@Override
public long skip(long n) {
return i.skip(intDisplacement(n));
}
@Override
public boolean hasNext() {
return i.hasNext();
}
@Override
public boolean hasPrevious() {
return i.hasPrevious();
}
@Override
public float nextFloat() {
return i.nextFloat();
}
@Override
public float previousFloat() {
return i.previousFloat();
}
@Override
public long nextIndex() {
return i.nextIndex();
}
@Override
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 FloatBigListIterator asBigListIterator(final FloatListIterator i) {
return new BigListIteratorListIterator(i);
}
}