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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.objects;
import java.util.List;
import java.util.Collection;
import java.util.Random;
import java.util.RandomAccess;
/** A class providing static methods and objects that do useful things with type-specific lists.
*
* @see java.util.Collections
*/
public class ObjectLists {
private ObjectLists() {}
/** Shuffles the specified list using the specified pseudorandom number generator.
*
* @param l the list to be shuffled.
* @param random a pseudorandom number generator (please use a XorShift* generator).
* @return l.
*/
public static ObjectList shuffle(final ObjectList l, final Random random) {
for(int i = l.size(); i-- != 0;) {
final int p = random.nextInt(i + 1);
final K t = l.get(i);
l.set(i, l.get(p));
l.set(p, t);
}
return l;
}
/** An immutable class representing an empty type-specific list.
*
* This class may be useful to implement your own in case you subclass
* a type-specific list.
*/
public static class EmptyList extends ObjectCollections.EmptyCollection implements ObjectList , RandomAccess, java.io.Serializable, Cloneable {
private static final long serialVersionUID = -7046029254386353129L;
protected EmptyList() {}
@Override
public K get(int i) { throw new IndexOutOfBoundsException(); }
@Override
public boolean remove(Object k) { throw new UnsupportedOperationException(); }
@Override
public K remove(int i) { throw new UnsupportedOperationException(); }
@Override
public void add(final int index, final K k) { throw new UnsupportedOperationException(); }
@Override
public K set(final int index, final K k) { throw new UnsupportedOperationException(); }
@Override
public int indexOf(Object k) { return -1; }
@Override
public int lastIndexOf(Object k) { return -1; }
@Override
public boolean addAll(int i, Collection c) { throw new UnsupportedOperationException(); }
@SuppressWarnings("unchecked")
public ObjectListIterator listIterator() { return ObjectIterators.EMPTY_ITERATOR; }
@SuppressWarnings("unchecked")
public ObjectListIterator iterator() { return ObjectIterators.EMPTY_ITERATOR; }
@SuppressWarnings("unchecked")
public ObjectListIterator listIterator(int i) { if (i == 0) return ObjectIterators.EMPTY_ITERATOR; throw new IndexOutOfBoundsException(String.valueOf(i)); }
/** {@inheritDoc}
* @deprecated As of fastutil 5, replaced by {@link #listIterator()}. */
@Deprecated
@Override
public ObjectListIterator objectListIterator() { return listIterator(); }
/** {@inheritDoc}
* @deprecated As of fastutil 5, replaced by {@link #listIterator(int)}. */
@Deprecated
@Override
public ObjectListIterator objectListIterator(int i) { return listIterator(i); }
public ObjectList subList(int from, int to) { if (from == 0 && to == 0) return this; throw new IndexOutOfBoundsException(); }
/* {@inheritDoc}
* @deprecated As of fastutil 5, replaced by {@link #subList(int,int)}.
*/
@Deprecated
@Override
public ObjectList objectSubList(int from, int to) { return subList(from, to); }
@Override
public void getElements(int from, Object[] a, int offset, int length) { if (from == 0 && length == 0 && offset >= 0 && offset <= a.length) return; throw new IndexOutOfBoundsException(); }
@Override
public void removeElements(int from, int to) { throw new UnsupportedOperationException(); }
@Override
public void addElements(int index, final K a[], int offset, int length) { throw new UnsupportedOperationException(); }
@Override
public void addElements(int index, final K a[]) { throw new UnsupportedOperationException(); }
@Override
public void size(int s) { throw new UnsupportedOperationException(); }
@Override
public int compareTo(final List o) {
if (o == this) return 0;
return ((List)o).isEmpty() ? 0 : -1;
}
@Override
public Object clone() { return EMPTY_LIST; }
@Override
public int hashCode() { return 1; }
@Override
@SuppressWarnings("rawtypes")
public boolean equals(Object o) { return o instanceof List && ((List)o).isEmpty(); }
@Override
public String toString() { return "[]"; }
private Object readResolve() { return EMPTY_LIST; }
}
/** An empty list (immutable). It is serializable and cloneable.
*/
@SuppressWarnings("rawtypes")
public static final EmptyList EMPTY_LIST = new EmptyList();
/** Returns an empty list (immutable). It is serializable and cloneable.
*
* This method provides a typesafe access to {@link #EMPTY_LIST}.
* @return an empty list (immutable).
*/
@SuppressWarnings("unchecked")
public static ObjectList emptyList() {
return EMPTY_LIST;
}
/** An immutable class representing a type-specific singleton list.
*
* This class may be useful to implement your own in case you subclass
* a type-specific list.
*/
public static class Singleton extends AbstractObjectList implements RandomAccess, java.io.Serializable, Cloneable {
private static final long serialVersionUID = -7046029254386353129L;
private final K element;
private Singleton(final K element) {
this.element = element;
}
@Override
public K get(final int i) { if (i == 0) return element; throw new IndexOutOfBoundsException(); }
@Override
public boolean remove(Object k) { throw new UnsupportedOperationException(); }
@Override
public K remove(final int i) { throw new UnsupportedOperationException(); }
@Override
public boolean contains(final Object k) { return ( (k) == null ? (element) == null : (k).equals(element) ); }
/* Slightly optimized w.r.t. the one in ABSTRACT_SET. */
@Override
public Object[] toArray() {
Object a[] = new Object[1];
a[0] = element;
return a;
}
@Override
public ObjectListIterator listIterator() { return ObjectIterators.singleton(element); }
@Override
public ObjectListIterator iterator() { return listIterator(); }
@Override
public ObjectListIterator listIterator(int i) {
if (i > 1 || i < 0) throw new IndexOutOfBoundsException();
ObjectListIterator l = listIterator();
if (i == 1) l.next();
return l;
}
@Override
@SuppressWarnings("unchecked")
public ObjectList subList(final int from, final int to) {
ensureIndex(from);
ensureIndex(to);
if (from > to) throw new IndexOutOfBoundsException("Start index (" + from + ") is greater than end index (" + to + ")");
if (from != 0 || to != 1) return EMPTY_LIST;
return this;
}
@Override
public boolean addAll(int i, Collection c) { throw new UnsupportedOperationException(); }
@Override
public boolean addAll(final Collection 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 int size() { return 1; }
@Override
public void size(final int size) { throw new UnsupportedOperationException(); }
@Override
public void clear() { throw new UnsupportedOperationException(); }
@Override
public Object clone() { return this; }
}
/** Returns a type-specific immutable list containing only the specified element. The returned list is serializable and cloneable.
*
* @param element the only element of the returned list.
* @return a type-specific immutable list containing just element.
*/
public static ObjectList singleton(final K element) { return new Singleton (element); }
/** A synchronized wrapper class for lists. */
public static class SynchronizedList extends ObjectCollections.SynchronizedCollection implements ObjectList , java.io.Serializable {
private static final long serialVersionUID = -7046029254386353129L;
protected final ObjectList list; // Due to the large number of methods that are not in COLLECTION, this is worth caching.
protected SynchronizedList(final ObjectList l, final Object sync) {
super(l, sync);
this.list = l;
}
protected SynchronizedList(final ObjectList l) {
super(l);
this.list = l;
}
@Override
public K get(final int i) { synchronized(sync) { return list.get(i); } }
@Override
public K set(final int i, final K k) { synchronized(sync) { return list.set(i, k); } }
@Override
public void add(final int i, final K k) { synchronized(sync) { list.add(i, k); } }
@Override
public K remove(final int i) { synchronized(sync) { return list.remove(i); } }
@Override
public int indexOf(final Object k) { synchronized(sync) { return list.indexOf(k); } }
@Override
public int lastIndexOf(final Object k) { synchronized(sync) { return list.lastIndexOf(k); } }
@Override
public boolean addAll(final int index, final Collection c) { synchronized(sync) { return list.addAll(index, c); } }
@Override
public void getElements(final int from, final Object a[], final int offset, final int length) { synchronized(sync) { list.getElements(from, a, offset, length); } }
@Override
public void removeElements(final int from, final int to) { synchronized(sync) { list.removeElements(from, to); } }
@Override
public void addElements(int index, final K a[], int offset, int length) { synchronized(sync) { list.addElements(index, a, offset, length); } }
@Override
public void addElements(int index, final K a[]) { synchronized(sync) { list.addElements(index, a); } }
@Override
public void size(final int size) { synchronized(sync) { list.size(size); } }
@Override
public ObjectListIterator listIterator() { return list.listIterator(); }
@Override
public ObjectListIterator iterator() { return listIterator(); }
@Override
public ObjectListIterator listIterator(final int i) { return list.listIterator(i); }
/** Returns a type-specific list iterator on the list.
*
* @see #listIterator()
* @deprecated As of fastutil 5, replaced by {@link #listIterator()}.
*/
@Deprecated
@Override
public ObjectListIterator objectListIterator() { return listIterator(); }
/** Returns a type-specific list iterator on the list.
*
* @see #listIterator()
* @deprecated As of fastutil 5, replaced by {@link #listIterator(int)}.
*/
@Deprecated
@Override
public ObjectListIterator objectListIterator(final int i) { return listIterator(i); }
@Override
public ObjectList subList(final int from, final int to) { synchronized(sync) { return new SynchronizedList (list.subList(from, to), sync); } }
/* {@inheritDoc}
* @deprecated As of fastutil 5, replaced by {@link #subList(int,int)}.
*/
@Deprecated
@Override
public ObjectList objectSubList(final int from, final int to) { return subList(from, to); }
@Override
public boolean equals(final Object o) { if (o == this) return true; synchronized(sync) { return collection.equals(o); } }
@Override
public int hashCode() { synchronized(sync) { return collection.hashCode(); } }
@Override
public int compareTo(final List o) { synchronized(sync) { return list.compareTo(o); } }
private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException {
synchronized(sync) { s.defaultWriteObject(); }
}
}
/** A synchronized wrapper class for random-access lists. */
public static class SynchronizedRandomAccessList extends SynchronizedList implements RandomAccess, java.io.Serializable {
private static final long serialVersionUID = 0L;
protected SynchronizedRandomAccessList(final ObjectList l, final Object sync) {
super(l, sync);
}
protected SynchronizedRandomAccessList(final ObjectList l) {
super(l);
}
@Override
public ObjectList subList(final int from, final int to) { synchronized(sync) { return new SynchronizedRandomAccessList (list.subList(from, to), sync); } }
}
/** Returns a synchronized type-specific list backed by the given type-specific list.
*
* @param l the list to be wrapped in a synchronized list.
* @return a synchronized view of the specified list.
* @see java.util.Collections#synchronizedList(List)
*/
public static ObjectList synchronize(final ObjectList l) {
return l instanceof RandomAccess ? new SynchronizedRandomAccessList (l) : new SynchronizedList (l);
}
/** Returns a synchronized type-specific list backed by the given type-specific list, using an assigned object to synchronize.
*
* @param l the list to be wrapped in a synchronized list.
* @param sync an object that will be used to synchronize the access to the list.
* @return a synchronized view of the specified list.
* @see java.util.Collections#synchronizedList(List)
*/
public static ObjectList synchronize(final ObjectList l, final Object sync) {
return l instanceof RandomAccess ? new SynchronizedRandomAccessList (l, sync) : new SynchronizedList (l, sync);
}
/** An unmodifiable wrapper class for lists. */
public static class UnmodifiableList extends ObjectCollections.UnmodifiableCollection implements ObjectList , java.io.Serializable {
private static final long serialVersionUID = -7046029254386353129L;
protected final ObjectList list; // Due to the large number of methods that are not in COLLECTION, this is worth caching.
protected UnmodifiableList(final ObjectList l) {
super(l);
this.list = l;
}
@Override
public K get(final int i) { return list.get(i); }
@Override
public K set(final int i, final K k) { throw new UnsupportedOperationException(); }
@Override
public void add(final int i, final K k) { throw new UnsupportedOperationException(); }
@Override
public K remove(final int i) { throw new UnsupportedOperationException(); }
@Override
public int indexOf(final Object k) { return list.indexOf(k); }
@Override
public int lastIndexOf(final Object k) { return list.lastIndexOf(k); }
@Override
public boolean addAll(final int index, final Collection c) { throw new UnsupportedOperationException(); }
@Override
public void getElements(final int from, final Object a[], final int offset, final int length) { list.getElements(from, a, offset, length); }
@Override
public void removeElements(final int from, final int to) { throw new UnsupportedOperationException(); }
@Override
public void addElements(int index, final K a[], int offset, int length) { throw new UnsupportedOperationException(); }
@Override
public void addElements(int index, final K a[]) { throw new UnsupportedOperationException(); }
@Override
public void size(final int size) { list.size(size); }
@Override
public ObjectListIterator listIterator() { return ObjectIterators.unmodifiable(list.listIterator()); }
@Override
public ObjectListIterator iterator() { return listIterator(); }
@Override
public ObjectListIterator listIterator(final int i) { return ObjectIterators.unmodifiable(list.listIterator(i)); }
/** Returns a type-specific list iterator on the list.
*
* @see #listIterator()
* @deprecated As of fastutil 5, replaced by {@link #listIterator()}.
*/
@Deprecated
@Override
public ObjectListIterator objectListIterator() { return listIterator(); }
/** Returns a type-specific list iterator on the list.
*
* @see #listIterator()
* @deprecated As of fastutil 5, replaced by {@link #listIterator(int)}.
*/
@Deprecated
@Override
public ObjectListIterator objectListIterator(final int i) { return listIterator(i); }
public ObjectList subList(final int from, final int to) { return new UnmodifiableList (list.subList(from, to)); }
/* {@inheritDoc}
* @deprecated As of fastutil 5, replaced by {@link #subList(int,int)}.
*/
@Deprecated
@Override
public ObjectList objectSubList(final int from, final int to) { return subList(from, to); }
@Override
public boolean equals(final Object o) { if (o == this) return true; return collection.equals(o); }
@Override
public int hashCode() { return collection.hashCode(); }
@Override
public int compareTo(final List o) { return list.compareTo(o); }
}
/** An unmodifiable wrapper class for random-access lists. */
public static class UnmodifiableRandomAccessList extends UnmodifiableList implements RandomAccess, java.io.Serializable {
private static final long serialVersionUID = 0L;
protected UnmodifiableRandomAccessList(final ObjectList l) {
super(l);
}
@Override
public ObjectList subList(final int from, final int to) { return new UnmodifiableRandomAccessList (list.subList(from, to)); }
}
/** Returns an unmodifiable type-specific list backed by the given type-specific list.
*
* @param l the list to be wrapped in an unmodifiable list.
* @return an unmodifiable view of the specified list.
* @see java.util.Collections#unmodifiableList(List)
*/
public static ObjectList unmodifiable(final ObjectList l) {
return l instanceof RandomAccess ? new UnmodifiableRandomAccessList (l) : new UnmodifiableList (l);
}
}