it.unimi.dsi.fastutil.booleans

Class BooleanLists.SynchronizedList

java.lang.Object

it.unimi.dsi.fastutil.booleans.BooleanLists.SynchronizedList

All Implemented Interfaces:

BooleanCollection, BooleanIterable, BooleanList, java.io.Serializable, java.lang.Comparable<java.util.List<? extends java.lang.Boolean>>, java.lang.Iterable<java.lang.Boolean>, java.util.Collection<java.lang.Boolean>, java.util.List<java.lang.Boolean>

Direct Known Subclasses:

BooleanLists.SynchronizedRandomAccessList

Enclosing class:

BooleanLists

public static class BooleanLists.SynchronizedList
extends java.lang.Object
implements BooleanList, java.io.Serializable

A synchronized wrapper class for lists.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected BooleanCollection	collection
protected BooleanList	list
protected java.lang.Object	sync

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	SynchronizedList(BooleanList l)
protected	SynchronizedList(BooleanList l, java.lang.Object sync)

Method Summary

Modifier and Type	Method and Description
boolean	add(boolean k) Ensures that this collection contains the specified element (optional operation).
boolean	add(java.lang.Boolean k) Deprecated.
void	add(int i, boolean k) Inserts the specified element at the specified position in this list (optional operation).
void	add(int i, java.lang.Boolean k) Deprecated. Please use the corresponding type-specific method instead.
boolean	addAll(BooleanCollection c) Adds all elements of the given type-specific collection to this collection.
boolean	addAll(BooleanList l) Appends all of the elements in the specified type-specific list to the end of this type-specific list (optional operation).
boolean	addAll(java.util.Collection<? extends java.lang.Boolean> c)
boolean	addAll(int index, BooleanCollection c) Inserts all of the elements in the specified type-specific collection into this type-specific list at the specified position (optional operation).
boolean	addAll(int index, BooleanList l) Inserts all of the elements in the specified type-specific list into this type-specific list at the specified position (optional operation).
boolean	addAll(int index, java.util.Collection<? extends java.lang.Boolean> c)
void	addElements(int index, boolean[] a) Add (hopefully quickly) elements to this type-specific list.
void	addElements(int index, boolean[] a, int offset, int length) Add (hopefully quickly) elements to this type-specific list.
void	clear()
int	compareTo(java.util.List<? extends java.lang.Boolean> o)
boolean	contains(boolean k) Returns true if this collection contains the specified element.
boolean	contains(java.lang.Object k) Deprecated.
boolean	containsAll(BooleanCollection c) Checks whether this collection contains all elements from the given type-specific collection.
boolean	containsAll(java.util.Collection<?> c)
boolean	equals(java.lang.Object o)
void	forEach(it.unimi.dsi.fastutil.booleans.BooleanConsumer action) Performs the given action for each element of this type-specific Iterable until all elements have been processed or the action throws an exception.
java.lang.Boolean	get(int i) Deprecated. Please use the corresponding type-specific method instead.
boolean	getBoolean(int i) Returns the element at the specified position in this list.
void	getElements(int from, boolean[] a, int offset, int length) Copies (hopefully quickly) elements of this type-specific list into the given array.
int	hashCode()
int	indexOf(boolean k) Returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element.
int	indexOf(java.lang.Object o) Deprecated. Please use the corresponding type-specific method instead.
boolean	isEmpty()
BooleanListIterator	iterator() Returns a type-specific iterator on the elements of this collection.
int	lastIndexOf(boolean k) Returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element.
int	lastIndexOf(java.lang.Object o) Deprecated. Please use the corresponding type-specific method instead.
BooleanListIterator	listIterator() Returns a type-specific list iterator on the list.
BooleanListIterator	listIterator(int i) Returns a type-specific list iterator on the list starting at a given index.
java.util.stream.Stream<java.lang.Boolean>	parallelStream()
boolean	rem(boolean k) Removes a single instance of the specified element from this collection, if it is present (optional operation).
java.lang.Boolean	remove(int i) Deprecated. Please use the corresponding type-specific method instead.
boolean	remove(java.lang.Object k) Deprecated.
boolean	removeAll(BooleanCollection c) Remove from this collection all elements in the given type-specific collection.
boolean	removeAll(java.util.Collection<?> c)
boolean	removeBoolean(int i) Removes the element at the specified position in this list (optional operation).
void	removeElements(int from, int to) Removes (hopefully quickly) elements of this type-specific list.
boolean	removeIf(BooleanPredicate filter) Remove from this collection all elements which satisfy the given predicate.
void	replaceAll(BooleanUnaryOperator operator) Replaces each element of this list with the result of applying the operator to that element.
boolean	retainAll(BooleanCollection c) Retains in this collection only elements from the given type-specific collection.
boolean	retainAll(java.util.Collection<?> c)
boolean	set(int i, boolean k) Replaces the element at the specified position in this list with the specified element (optional operation).
java.lang.Boolean	set(int index, java.lang.Boolean k) Deprecated. Please use the corresponding type-specific method instead.
void	setElements(boolean[] a) Set (hopefully quickly) elements to match the array given.
void	setElements(int index, boolean[] a) Set (hopefully quickly) elements to match the array given.
void	setElements(int index, boolean[] a, int offset, int length) Set (hopefully quickly) elements to match the array given.
int	size()
void	size(int size) Sets the size of this list.
void	sort(it.unimi.dsi.fastutil.booleans.BooleanComparator comparator) Sort a list using a type-specific comparator.
void	sort(java.util.Comparator<? super java.lang.Boolean> comparator) Deprecated.
it.unimi.dsi.fastutil.booleans.BooleanSpliterator	spliterator() Returns a type-specific spliterator on the elements of this collection.
java.util.stream.Stream<java.lang.Boolean>	stream()
BooleanList	subList(int from, int to) Returns a type-specific view of the portion of this list from the index from, inclusive, to the index to, exclusive.
java.lang.Object[]	toArray()
boolean[]	toArray(boolean[] a) Returns an array containing all of the elements in this collection; the runtime type of the returned array is that of the specified array.
<T> T[]	toArray(T[] a)
boolean[]	toBooleanArray() Returns a primitive type array containing the items of this collection.
boolean[]	toBooleanArray(boolean[] a) Deprecated.
java.lang.String	toString()
void	unstableSort(it.unimi.dsi.fastutil.booleans.BooleanComparator comparator) Sorts this list using a sort not assured to be stable.
void	unstableSort(java.util.Comparator<? super java.lang.Boolean> comparator) Deprecated.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface it.unimi.dsi.fastutil.booleans.BooleanList

add, add, contains, of, of, of, of, of, remove, replaceAll, spliterator

Methods inherited from interface java.util.List

addAll, clear, containsAll, isEmpty, removeAll, retainAll, size, toArray, toArray

Methods inherited from interface it.unimi.dsi.fastutil.booleans.BooleanCollection

addAll, contains, containsAll, rem, removeAll, removeIf, retainAll, toArray, toBooleanArray, toBooleanArray

Methods inherited from interface java.util.Collection

parallelStream, stream

Methods inherited from interface it.unimi.dsi.fastutil.booleans.BooleanIterable

forEach, forEach

Field Detail

list

protected final BooleanList list

collection

protected final BooleanCollection collection

sync

protected final java.lang.Object sync

Constructor Detail

SynchronizedList

protected SynchronizedList(BooleanList l,
                           java.lang.Object sync)

SynchronizedList

protected SynchronizedList(BooleanList l)

Method Detail

getBoolean

public boolean getBoolean(int i)

Description copied from interface: BooleanList

Returns the element at the specified position in this list.

Specified by:

getBoolean in interface BooleanList

See Also:

List.get(int)

set

public boolean set(int i,
                   boolean k)

Description copied from interface: BooleanList

Replaces the element at the specified position in this list with the specified element (optional operation).

Specified by:

set in interface BooleanList

See Also:

List.set(int,Object)

add

public void add(int i,
                boolean k)

Description copied from interface: BooleanList

Inserts the specified element at the specified position in this list (optional operation).

Specified by:

add in interface BooleanList

See Also:

List.add(int,Object)

removeBoolean

public boolean removeBoolean(int i)

Description copied from interface: BooleanList

Removes the element at the specified position in this list (optional operation).

Specified by:

removeBoolean in interface BooleanList

See Also:

List.remove(int)

indexOf

public int indexOf(boolean k)

Description copied from interface: BooleanList

Returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element.

Specified by:

indexOf in interface BooleanList

See Also:

List.indexOf(Object)

lastIndexOf

public int lastIndexOf(boolean k)

Description copied from interface: BooleanList

Returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element.

Specified by:

lastIndexOf in interface BooleanList

See Also:

List.lastIndexOf(Object)

removeIf

public boolean removeIf(BooleanPredicate filter)

Description copied from interface: BooleanCollection

Remove from this collection all elements which satisfy the given predicate.

Specified by:

removeIf in interface BooleanCollection

Parameters:

filter - a predicate which returns true for elements to be removed.

Returns:

true if any elements were removed.

See Also:

Collection.removeIf(java.util.function.Predicate)

replaceAll

public void replaceAll(BooleanUnaryOperator operator)

Description copied from interface: BooleanList

Replaces each element of this list with the result of applying the operator to that element.

Specified by:

replaceAll in interface BooleanList

Parameters:

operator - the operator to apply to each element.

See Also:

List.replaceAll(java.util.function.UnaryOperator<E>)

addAll

public boolean addAll(int index,
                      java.util.Collection<? extends java.lang.Boolean> c)

Specified by:

addAll in interface java.util.List<java.lang.Boolean>

getElements

public void getElements(int from,
                        boolean[] a,
                        int offset,
                        int length)

Description copied from interface: BooleanList

Copies (hopefully quickly) elements of this type-specific list into the given array.

Specified by:

getElements in interface BooleanList

Parameters:

from - the start index (inclusive).

a - the destination array.

offset - the offset into the destination array where to store the first element copied.

length - the number of elements to be copied.

removeElements

public void removeElements(int from,
                           int to)

Description copied from interface: BooleanList

Removes (hopefully quickly) elements of this type-specific list.

Specified by:

removeElements in interface BooleanList

Parameters:

from - the start index (inclusive).

to - the end index (exclusive).

addElements

public void addElements(int index,
                        boolean[] a,
                        int offset,
                        int length)

Description copied from interface: BooleanList

Add (hopefully quickly) elements to this type-specific list.

Specified by:

addElements in interface BooleanList

Parameters:

index - the index at which to add elements.

a - the array containing the elements.

offset - the offset of the first element to add.

length - the number of elements to add.

addElements

public void addElements(int index,
                        boolean[] a)

Description copied from interface: BooleanList

Add (hopefully quickly) elements to this type-specific list.

Specified by:

addElements in interface BooleanList

Parameters:

index - the index at which to add elements.

a - the array containing the elements.

setElements

public void setElements(boolean[] a)

Description copied from interface: BooleanList

Set (hopefully quickly) elements to match the array given.

Specified by:

setElements in interface BooleanList

Parameters:

a - the array containing the elements.

setElements

public void setElements(int index,
                        boolean[] a)

Description copied from interface: BooleanList

Set (hopefully quickly) elements to match the array given.

Specified by:

setElements in interface BooleanList

Parameters:

index - the index at which to start setting elements.

a - the array containing the elements.

setElements

public void setElements(int index,
                        boolean[] a,
                        int offset,
                        int length)

Description copied from interface: BooleanList

Set (hopefully quickly) elements to match the array given. Sets each in this list to the corresponding elements in the array, as if by

 ListIterator iter = listIterator(index);
 int i = 0;
 while (i < length) {
   iter.next();
   iter.set(a[offset + i++]);
 }
 

However, the exact implementation may be more efficient, taking into account whether random access is faster or not, or at the discretion of subclasses, abuse internals.

Specified by:

setElements in interface BooleanList

Parameters:

index - the index at which to start setting elements.

a - the array containing the elements

offset - the offset of the first element to add.

length - the number of elements to add.

size

public void size(int size)

Description copied from interface: BooleanList

Sets the size of this list.

If the specified size is smaller than the current size, the last elements are discarded. Otherwise, they are filled with 0/null/false.

Specified by:

size in interface BooleanList

Parameters:

size - the new size.

listIterator

public BooleanListIterator listIterator()

Description copied from interface: BooleanList

Returns a type-specific list iterator on the list.

Specified by:

listIterator in interface BooleanList

Specified by:

listIterator in interface java.util.List<java.lang.Boolean>

See Also:

List.listIterator()

iterator

public BooleanListIterator iterator()

Description copied from interface: BooleanCollection

Returns a type-specific iterator on the elements of this collection.

Specified by:

iterator in interface BooleanCollection

Specified by:

iterator in interface BooleanIterable

Specified by:

iterator in interface BooleanList

Specified by:

iterator in interface java.lang.Iterable<java.lang.Boolean>

Specified by:

iterator in interface java.util.Collection<java.lang.Boolean>

Specified by:

iterator in interface java.util.List<java.lang.Boolean>

Returns:

a type-specific iterator on the elements of this collection.

See Also:

Iterable.iterator()

listIterator

public BooleanListIterator listIterator(int i)

Description copied from interface: BooleanList

Returns a type-specific list iterator on the list starting at a given index.

Specified by:

listIterator in interface BooleanList

Specified by:

listIterator in interface java.util.List<java.lang.Boolean>

See Also:

List.listIterator(int)

subList

public BooleanList subList(int from,
                           int to)

Description copied from interface: BooleanList

Returns a type-specific view of the portion of this list from the index from, inclusive, to the index to, exclusive.

Specified by:

subList in interface BooleanList

Specified by:

subList in interface java.util.List<java.lang.Boolean>

See Also:

List.subList(int,int)

equals

public boolean equals(java.lang.Object o)

Specified by:

equals in interface java.util.Collection<java.lang.Boolean>

Specified by:

equals in interface java.util.List<java.lang.Boolean>

hashCode

public int hashCode()

Specified by:

hashCode in interface java.util.Collection<java.lang.Boolean>

Specified by:

hashCode in interface java.util.List<java.lang.Boolean>

compareTo

public int compareTo(java.util.List<? extends java.lang.Boolean> o)

Specified by:

compareTo in interface java.lang.Comparable<java.util.List<? extends java.lang.Boolean>>

addAll

public boolean addAll(int index,
                      BooleanCollection c)

Description copied from interface: BooleanList

Inserts all of the elements in the specified type-specific collection into this type-specific list at the specified position (optional operation).

Specified by:

addAll in interface BooleanList

See Also:

List.addAll(int,java.util.Collection)

addAll

public boolean addAll(int index,
                      BooleanList l)

Description copied from interface: BooleanList

Inserts all of the elements in the specified type-specific list into this type-specific list at the specified position (optional operation).

Specified by:

addAll in interface BooleanList

See Also:

List.addAll(int,Collection)

addAll

public boolean addAll(BooleanList l)

Description copied from interface: BooleanList

Appends all of the elements in the specified type-specific list to the end of this type-specific list (optional operation).

Specified by:

addAll in interface BooleanList

See Also:

List.addAll(Collection)

get

@Deprecated
public java.lang.Boolean get(int i)

Deprecated. Please use the corresponding type-specific method instead.

Specified by:

get in interface BooleanList

Specified by:

get in interface java.util.List<java.lang.Boolean>

add

@Deprecated
public void add(int i,
                            java.lang.Boolean k)

Deprecated. Please use the corresponding type-specific method instead.

Specified by:

add in interface BooleanList

Specified by:

add in interface java.util.List<java.lang.Boolean>

set

@Deprecated
public java.lang.Boolean set(int index,
                                         java.lang.Boolean k)

Deprecated. Please use the corresponding type-specific method instead.

Specified by:

set in interface BooleanList

Specified by:

set in interface java.util.List<java.lang.Boolean>

remove

@Deprecated
public java.lang.Boolean remove(int i)

Deprecated. Please use the corresponding type-specific method instead.

Specified by:

remove in interface BooleanList

Specified by:

remove in interface java.util.List<java.lang.Boolean>

indexOf

@Deprecated
public int indexOf(java.lang.Object o)

Deprecated. Please use the corresponding type-specific method instead.

Specified by:

indexOf in interface BooleanList

Specified by:

indexOf in interface java.util.List<java.lang.Boolean>

lastIndexOf

@Deprecated
public int lastIndexOf(java.lang.Object o)

Deprecated. Please use the corresponding type-specific method instead.

Specified by:

lastIndexOf in interface BooleanList

Specified by:

lastIndexOf in interface java.util.List<java.lang.Boolean>

sort

public void sort(it.unimi.dsi.fastutil.booleans.BooleanComparator comparator)

Description copied from interface: BooleanList

Sort a list using a type-specific comparator.

Pass null to sort using natural ordering.

Specified by:

sort in interface BooleanList

See Also:

List.sort(java.util.Comparator)

unstableSort

public void unstableSort(it.unimi.dsi.fastutil.booleans.BooleanComparator comparator)

Description copied from interface: BooleanList

Sorts this list using a sort not assured to be stable.

Pass null to sort using natural ordering.

This differs from List.sort(java.util.Comparator) in that the results are not assured to be stable, but may be a bit faster.

Unless a subclass specifies otherwise, the results of the method if the list is concurrently modified during the sort are unspecified.

Specified by:

unstableSort in interface BooleanList

sort

@Deprecated
public void sort(java.util.Comparator<? super java.lang.Boolean> comparator)

Deprecated.

Description copied from interface: BooleanList

Specified by:

sort in interface BooleanList

Specified by:

sort in interface java.util.List<java.lang.Boolean>

unstableSort

@Deprecated
public void unstableSort(java.util.Comparator<? super java.lang.Boolean> comparator)

Deprecated.

Description copied from interface: BooleanList

Sorts this list using a sort not assured to be stable.

Specified by:

unstableSort in interface BooleanList

add

public boolean add(boolean k)

Description copied from interface: BooleanCollection

Ensures that this collection contains the specified element (optional operation).

Specified by:

add in interface BooleanCollection

See Also:

Collection.add(Object)

contains

public boolean contains(boolean k)

Description copied from interface: BooleanCollection

Returns true if this collection contains the specified element.

Specified by:

contains in interface BooleanCollection

See Also:

Collection.contains(Object)

rem

public boolean rem(boolean k)

Description copied from interface: BooleanCollection

Removes a single instance of the specified element from this collection, if it is present (optional operation).

Note that this method should be called remove(), but the clash with the similarly named index-based method in the List interface forces us to use a distinguished name. For simplicity, the set interfaces reinstates remove().

Specified by:

rem in interface BooleanCollection

See Also:

Collection.remove(Object)

size

public int size()

Specified by:

size in interface java.util.Collection<java.lang.Boolean>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface java.util.Collection<java.lang.Boolean>

toBooleanArray

public boolean[] toBooleanArray()

Description copied from interface: BooleanCollection

Returns a primitive type array containing the items of this collection.

Specified by:

toBooleanArray in interface BooleanCollection

Returns:

a primitive type array containing the items of this collection.

See Also:

Collection.toArray()

toArray

public java.lang.Object[] toArray()

Specified by:

toArray in interface java.util.Collection<java.lang.Boolean>

toBooleanArray

@Deprecated
public boolean[] toBooleanArray(boolean[] a)

Deprecated.

Description copied from interface: BooleanCollection

Returns a primitive type array containing the items of this collection.

Note that, contrarily to Collection.toArray(Object[]), this methods just writes all elements of this collection: no special value will be added after the last one.

Specified by:

toBooleanArray in interface BooleanCollection

Parameters:

a - if this array is big enough, it will be used to store this collection.

Returns:

a primitive type array containing the items of this collection.

See Also:

Collection.toArray(Object[])

toArray

public boolean[] toArray(boolean[] a)

Description copied from interface: BooleanCollection

Returns an array containing all of the elements in this collection; the runtime type of the returned array is that of the specified array.

Note that, contrarily to Collection.toArray(Object[]), this methods just writes all elements of this collection: no special value will be added after the last one.

Specified by:

toArray in interface BooleanCollection

Parameters:

a - if this array is big enough, it will be used to store this collection.

Returns:

a primitive type array containing the items of this collection.

See Also:

Collection.toArray(Object[])

addAll

public boolean addAll(BooleanCollection c)

Description copied from interface: BooleanCollection

Adds all elements of the given type-specific collection to this collection.

Specified by:

addAll in interface BooleanCollection

Parameters:

c - a type-specific collection.

Returns:

true if this collection changed as a result of the call.

See Also:

Collection.addAll(Collection)

containsAll

public boolean containsAll(BooleanCollection c)

Description copied from interface: BooleanCollection

Checks whether this collection contains all elements from the given type-specific collection.

Specified by:

containsAll in interface BooleanCollection

Parameters:

c - a type-specific collection.

Returns:

true if this collection contains all elements of the argument.

See Also:

Collection.containsAll(Collection)

removeAll

public boolean removeAll(BooleanCollection c)

Description copied from interface: BooleanCollection

Remove from this collection all elements in the given type-specific collection.

Specified by:

removeAll in interface BooleanCollection

Parameters:

c - a type-specific collection.

Returns:

true if this collection changed as a result of the call.

See Also:

Collection.removeAll(Collection)

retainAll

public boolean retainAll(BooleanCollection c)

Description copied from interface: BooleanCollection

Retains in this collection only elements from the given type-specific collection.

Specified by:

retainAll in interface BooleanCollection

Parameters:

c - a type-specific collection.

Returns:

true if this collection changed as a result of the call.

See Also:

Collection.retainAll(Collection)

add

@Deprecated
public boolean add(java.lang.Boolean k)

Deprecated.

Description copied from interface: BooleanCollection

Specified by:

add in interface BooleanCollection

Specified by:

add in interface java.util.Collection<java.lang.Boolean>

contains

@Deprecated
public boolean contains(java.lang.Object k)

Deprecated.

Description copied from interface: BooleanCollection

Specified by:

contains in interface BooleanCollection

Specified by:

contains in interface java.util.Collection<java.lang.Boolean>

remove

@Deprecated
public boolean remove(java.lang.Object k)

Deprecated.

Description copied from interface: BooleanCollection

Specified by:

remove in interface BooleanCollection

Specified by:

remove in interface java.util.Collection<java.lang.Boolean>

toArray

public <T> T[] toArray(T[] a)

Specified by:

toArray in interface java.util.Collection<java.lang.Boolean>

spliterator

public it.unimi.dsi.fastutil.booleans.BooleanSpliterator spliterator()

Description copied from interface: BooleanCollection

Returns a type-specific spliterator on the elements of this collection.

See Collection.spliterator() for more documentation on the requirements of the returned spliterator.

Specified by:

spliterator in interface BooleanCollection

Specified by:

spliterator in interface BooleanIterable

Specified by:

spliterator in interface java.lang.Iterable<java.lang.Boolean>

Specified by:

spliterator in interface java.util.Collection<java.lang.Boolean>

Returns:

a type-specific spliterator on the elements of this collection.

stream

public java.util.stream.Stream<java.lang.Boolean> stream()

Specified by:

stream in interface java.util.Collection<java.lang.Boolean>

parallelStream

public java.util.stream.Stream<java.lang.Boolean> parallelStream()

Specified by:

parallelStream in interface java.util.Collection<java.lang.Boolean>

forEach

public void forEach(it.unimi.dsi.fastutil.booleans.BooleanConsumer action)

Description copied from interface: BooleanIterable

Performs the given action for each element of this type-specific Iterable until all elements have been processed or the action throws an exception.

Specified by:

forEach in interface BooleanIterable

Parameters:

action - the action to be performed for each element.

See Also:

Iterable.forEach(java.util.function.Consumer)

addAll

public boolean addAll(java.util.Collection<? extends java.lang.Boolean> c)

Specified by:

addAll in interface java.util.Collection<java.lang.Boolean>

containsAll

public boolean containsAll(java.util.Collection<?> c)

Specified by:

containsAll in interface java.util.Collection<java.lang.Boolean>

removeAll

public boolean removeAll(java.util.Collection<?> c)

Specified by:

removeAll in interface java.util.Collection<java.lang.Boolean>

retainAll

public boolean retainAll(java.util.Collection<?> c)

Specified by:

retainAll in interface java.util.Collection<java.lang.Boolean>

clear

public void clear()

Specified by:

clear in interface java.util.Collection<java.lang.Boolean>

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object