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/*
* Java Genetic Algorithm Library (jenetics-3.0.1).
* Copyright (c) 2007-2015 Franz Wilhelmstötter
*
* 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.
*
* Author:
* Franz Wilhelmstötter ([email protected])
*/
package org.jenetics.util;
import static java.util.Objects.requireNonNull;
import static java.util.stream.Collectors.joining;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.Objects;
import java.util.RandomAccess;
import java.util.Spliterator;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.function.Supplier;
import java.util.stream.Collector;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
import org.jenetics.internal.collection.SeqSpliterator;
/**
* General interface for a ordered, fixed sized, object sequence.
*
* Use the {@link #asList()} method to work together with the
*
* Java Collection Framework.
*
* @author Franz Wilhelmstötter
* @since 1.0
* @version 3.0 — $Date: 2014-12-08 $
*/
public interface Seq extends Iterable {
/**
* Return the value at the given {@code index}.
*
* @param index index of the element to return.
* @return the value at the given {@code index}.
* @throws IndexOutOfBoundsException if the index is out of range
* (index < 0 || index >= size()).
*/
public T get(final int index);
/**
* Return the length of this sequence. Once the sequence is created, the
* length can't be changed.
*
* @return the length of this sequence.
*/
public int length();
/**
* @see #length()
* @return the size of this sequence
*/
public default int size() {
return length();
}
/**
* Tests whether a predicate holds for all elements of this sequence.
*
* @param predicate the predicate to use to test the elements.
* @return {@code true} if the given predicate p holds for all elements of
* this sequence, {@code false} otherwise.
* @throws NullPointerException if the given {@code predicate} is
* {@code null}.
*/
public default boolean forAll(final Predicate predicate) {
boolean valid = true;
if (this instanceof RandomAccess) {
for (int i = 0, n = length(); i < n && valid; ++i) {
valid = predicate.test(get(i));
}
} else {
final Iterator it = iterator();
while (it.hasNext() && valid) {
valid = predicate.test(it.next());
}
}
return valid;
}
/**
* Returns a sequential Stream with this sequence as its source.
*
* @since 3.0
*
* @return a sequential Stream over the elements in this sequence
*/
public default Stream stream() {
return StreamSupport.stream(new SeqSpliterator<>(this), false);
}
/**
* Returns a possibly parallel {@code Stream} with this sequence as its
* source. It is allowable for this method to return a sequential stream.
*
* @since 3.0
*
* @return a possibly parallel {@code Stream} over the elements in this
* collection
*/
public default Stream parallelStream() {
return StreamSupport.stream(new SeqSpliterator<>(this), true);
}
@Override
public default Spliterator spliterator() {
return new SeqSpliterator(this);
}
/**
* Returns {@code true} if this sequence contains the specified element.
*
* @param element element whose presence in this sequence is to be tested.
* The tested element can be {@code null}.
* @return {@code true} if this sequence contains the specified element
*/
public default boolean contains(final Object element) {
return indexOf(element) != -1;
}
/**
* Returns the index of the first occurrence of the specified element
* in this sequence, or -1 if this sequence does not contain the element.
*
* @param element element to search for, can be {@code null}
* @return the index of the first occurrence of the specified element in
* this sequence, or -1 if this sequence does not contain the element
*/
public default int indexOf(final Object element) {
return indexOf(element, 0, length());
}
/**
* Returns the index of the first occurrence of the specified element
* in this sequence, or -1 if this sequence does not contain the element.
*
* @param element element to search for, can be {@code null}
* @param start the start index (inclusively) for the element search.
* @return the index of the first occurrence of the specified element in
* this sequence, or -1 if this sequence does not contain the element
* @throws IndexOutOfBoundsException for an illegal end point index value
* ({@code start < 0 || start > length()}).
*/
public default int indexOf(final Object element, final int start) {
return indexOf(element, start, length());
}
/**
* Returns the index of the first occurrence of the specified element
* in this sequence, or -1 if this sequence does not contain the element.
*
* @param element element to search for, can be {@code null}
* @param start the start index (inclusively) for the element search.
* @param end the end index (exclusively) for the element search.
* @return the index of the first occurrence of the specified element in
* this sequence, or -1 if this sequence does not contain the element
* @throws IndexOutOfBoundsException for an illegal end point index value
* ({@code start < 0 || end > length() || start > end}).
*/
public default int indexOf(final Object element, final int start, final int end) {
return element != null ?
indexWhere(element::equals, start, end) :
indexWhere(Objects::isNull, start, end);
}
/**
*
* Returns the index of the first element on which the given predicate
* returns {@code true}, or -1 if the predicate returns false for every
* sequence element.
*
* [code]
* // Finding index of first null value.
* final int index = seq.indexOf(o -> o == null);
*
* // Assert of no null values.
* assert (sequence.indexOf(o -> o == null) == -1);
* [/code]
*
* @param predicate the search predicate.
* @return the index of the first element on which the given predicate
* returns {@code true}, or -1 if the predicate returns {@code false}
* for every sequence element.
* @throws NullPointerException if the given {@code predicate} is {@code null}.
*/
public default int indexWhere(final Predicate predicate) {
return indexWhere(predicate, 0, length());
}
/**
*
* Returns the index of the first element on which the given predicate
* returns {@code true}, or -1 if the predicate returns false for every
* sequence element.
*
* [code]
* // Finding index of first null value.
* final int index = seq.indexOf(o -> o == null);
*
* // Assert of no null values.
* assert (sequence.indexOf(o -> o == null) == -1);
* [/code]
*
* @param predicate the search predicate.
* @param start the search start index
* @return the index of the first element on which the given predicate
* returns {@code true}, or -1 if the predicate returns {@code false}
* for every sequence element.
* @throws NullPointerException if the given {@code predicate} is {@code null}.
* @throws IndexOutOfBoundsException for an illegal end point index value
* ({@code start < 0 || start > length()}).
*/
public default int indexWhere(
final Predicate predicate,
final int start
) {
return indexWhere(predicate, start, length());
}
/**
*
* Returns the index of the first element on which the given predicate
* returns {@code true}, or -1 if the predicate returns false for every
* sequence element.
*
* [code]
* // Finding index of first null value.
* final int index = seq.indexOf(o -> o == null);
*
* // Assert of no null values.
* assert (sequence.indexOf(o -> o == null) == -1);
* [/code]
*
* @param predicate the search predicate.
* @param start the search start index
* @param end the search end index
* @return the index of the first element on which the given predicate
* returns {@code true}, or -1 if the predicate returns {@code false}
* for every sequence element.
* @throws NullPointerException if the given {@code predicate} is {@code null}.
* @throws IndexOutOfBoundsException for an illegal end point index value
* ({@code start < 0 || end > length() || start > end}).
*/
public default int indexWhere(
final Predicate predicate,
final int start,
final int end
) {
requireNonNull(predicate, "Predicate");
int index = -1;
for (int i = 0, n = length(); i < n && index == -1; ++i) {
if (predicate.test(get(i))) {
index = i;
}
}
return index;
}
/**
* Returns the index of the last occurrence of the specified element
* in this sequence, or -1 if this sequence does not contain the element.
*
* @param element element to search for, can be {@code null}
* @return the index of the last occurrence of the specified element in
* this sequence, or -1 if this sequence does not contain the element
*/
public default int lastIndexOf(final Object element) {
return lastIndexOf(element, 0, length());
}
/**
* Returns the index of the last occurrence of the specified element
* in this sequence, or -1 if this sequence does not contain the element.
*
* @param element element to search for, can be {@code null}
* @param end the search end index
* @return the index of the last occurrence of the specified element in
* this sequence, or -1 if this sequence does not contain the element
* @throws IndexOutOfBoundsException for an illegal end point index value
* ({@code end < 0 || end > length()}).
*/
public default int lastIndexOf(final Object element, final int end) {
return lastIndexOf(element, 0, end);
}
/**
* Returns the index of the last occurrence of the specified element
* in this sequence, or -1 if this sequence does not contain the element.
*
* @param element element to search for, can be {@code null}
* @param start the search start index
* @param end the search end index
* @return the index of the last occurrence of the specified element in
* this sequence, or -1 if this sequence does not contain the element
* @throws IndexOutOfBoundsException for an illegal end point index value
* ({@code start < 0 || end > length() || start > end}).
*/
public default int lastIndexOf(
final Object element,
final int start,
final int end
) {
return element != null ?
lastIndexWhere(element::equals, start, end) :
lastIndexWhere(Objects::isNull, start, end);
}
/**
* Returns the index of the last element on which the given predicate
* returns {@code true}, or -1 if the predicate returns false for every
* sequence element.
*
* @param predicate the search predicate.
* @return the index of the last element on which the given predicate
* returns {@code true}, or -1 if the predicate returns false for
* every sequence element.
* @throws NullPointerException if the given {@code predicate} is {@code null}.
*/
public default int lastIndexWhere(final Predicate predicate) {
return lastIndexWhere(predicate, 0, length());
}
/**
* Returns the index of the last element on which the given predicate
* returns {@code true}, or -1 if the predicate returns false for every
* sequence element.
*
* @param predicate the search predicate.
* @param end the search end index
* @return the index of the last element on which the given predicate
* returns {@code true}, or -1 if the predicate returns false for
* every sequence element.
* @throws NullPointerException if the given {@code predicate} is {@code null}.
* @throws IndexOutOfBoundsException for an illegal end point index value
* ({@code end < 0 || end > length()}).
*/
public default int lastIndexWhere(
final Predicate predicate,
final int end
) {
return lastIndexWhere(predicate, 0, end);
}
/**
* Returns the index of the last element on which the given predicate
* returns {@code true}, or -1 if the predicate returns false for every
* sequence element.
*
* @param predicate the search predicate.
* @param start the search start index
* @param end the search end index
* @return the index of the last element on which the given predicate
* returns {@code true}, or -1 if the predicate returns false for
* every sequence element.
* @throws NullPointerException if the given {@code predicate} is {@code null}.
* @throws IndexOutOfBoundsException for an illegal end point index value
* ({@code start < 0 || end > length() || start > end}).
*/
public default int lastIndexWhere(
final Predicate predicate,
final int start,
final int end
) {
requireNonNull(predicate, "Predicate");
int index = -1;
for (int i = length(); --i >= 0 && index == -1;) {
if (predicate.test(get(i))) {
index = i;
}
}
return index;
}
/**
* Returns a fixed-size list backed by the specified sequence. (Changes to
* the returned list "write through" to the array.) The returned list is
* fixed size, serializable and implements {@link RandomAccess}.
*
* @return a list view of this sequence
*/
public List asList();
/**
* Builds a new sequence by applying a function to all elements of this
* sequence.
*
* @param the element type of the returned collection.
* @param mapper the function to apply to each element.
* @return a new sequence of type That resulting from applying the given
* function f to each element of this sequence and collecting the
* results.
* @throws NullPointerException if the element {@code mapper} is
* {@code null}.
*/
public Seq map(final Function mapper);
/**
* Return an array containing all of the elements in this sequence in right
* order. The returned array will be "safe" in that no references to it
* are maintained by this sequence. (In other words, this method must allocate
* a new array.) The caller is thus free to modify the returned array.
*
* @see java.util.Collection#toArray()
*
* @return an array containing all of the elements in this list in right
* order
*/
public default Object[] toArray() {
final Object[] array = new Object[size()];
for (int i = size(); --i >= 0;) {
array[i] = get(i);
}
return array;
}
/**
* Return an array containing all of the elements in this sequence in right
* order; the runtime type of the returned array is that of the specified
* array. If this sequence fits in the specified array, it is returned
* therein. Otherwise, a new array is allocated with the runtime type of the
* specified array and the length of this array.
*
* If this sequence fits in the specified array with room to spare (i.e.,
* the array has more elements than this array), the element in the array
* immediately following the end of this array is set to null. (This is
* useful in determining the length of the array only if the caller knows
* that the list does not contain any null elements.)
*
* @see java.util.Collection#toArray(Object[])
*
* @param array the array into which the elements of this array are to be
* stored, if it is big enough; otherwise, a new array of the same
* runtime type is allocated for this purpose.
* @return an array containing the elements of this array
* @throws ArrayStoreException if the runtime type of the specified array is
* not a super type of the runtime type of every element in this
* array
* @throws NullPointerException if the given array is {@code null}.
*/
@SuppressWarnings("unchecked")
public default T[] toArray(final T[] array) {
if (array.length < length()) {
final T[] copy = (T[])java.lang.reflect.Array.newInstance(
array.getClass().getComponentType(), length()
);
for (int i = length(); --i >= 0;) {
copy[i] = get(i);
}
return copy;
}
for (int i = 0, n = length(); i < n; ++i) {
array[i] = get(i);
}
return array;
}
/**
* Returns a view of the portion of this sequence between the specified
* {@code start}, inclusive, and {@code end}, exclusive. (If {@code start}
* and {@code end} are equal, the returned sequence has the length zero.)
* The returned sequence is backed by this sequence, so non-structural
* changes in the returned sequence are reflected in this sequence, and
* vice-versa.
*
* This method eliminates the need for explicit range operations (of the
* populationSort that commonly exist for arrays). Any operation that
* expects an sequence can be used as a range operation by passing an sub
* sequence view instead of an whole sequence.
*
* @param start low end point (inclusive) of the sub array.
* @return a view of the specified range within this array.
* @throws IndexOutOfBoundsException for an illegal end point index value
* ({@code start < 0 || start > length()}).
*/
public Seq subSeq(final int start);
/**
* Returns a view of the portion of this sequence between the specified
* {@code start}, inclusive, and {@code end}, exclusive. (If {@code start}
* and {@code end} are equal, the returned sequence has the length zero.)
* The returned sequence is backed by this sequence, so non-structural
* changes in the returned sequence are reflected in this array, and
* vice-versa.
*
* This method eliminates the need for explicit range operations (of the
* populationSort that commonly exist for arrays). Any operation that
* expects an array can be used as a range operation by passing an sub
* sequence view instead of an whole sequence.
*
* @param start low end point (inclusive) of the sub sequence.
* @param end high end point (exclusive) of the sub sequence.
* @return a view of the specified range within this sequence.
* @throws IndexOutOfBoundsException for an illegal end point index value
* ({@code start < 0 || end > length() || start > end}).
*/
public Seq subSeq(final int start, final int end);
/**
* Test whether the given array is sorted in ascending order.
*
* @return {@code true} if the given {@code array} is sorted in ascending
* order, {@code false} otherwise.
* @throws NullPointerException if the given array or one of it's element is
* {@code null}.
*/
@SuppressWarnings("unchecked")
public default boolean isSorted() {
boolean sorted = true;
for (int i = 0, n = length() - 1; i < n && sorted; ++i) {
sorted = ((Comparable)get(i)).compareTo(get(i + 1)) <= 0;
}
return sorted;
}
/**
* Test whether the given array is sorted in ascending order. The order of
* the array elements is defined by the given comparator.
*
* @param comparator the comparator which defines the order.
* @return {@code true} if the given {@code array} is sorted in ascending
* order, {@code false} otherwise.
* @throws NullPointerException if the given array or one of it's element or
* the comparator is {@code null}.
*/
public default boolean isSorted(final Comparator comparator) {
boolean sorted = true;
for (int i = 0, n = length() - 1; i < n && sorted; ++i) {
sorted = comparator.compare(get(i), get(i + 1)) <= 0;
}
return sorted;
}
/**
* Returns the hash code value for this sequence. The hash code is defined
* as followed:
*
* [code]
* int hashCode = 1;
* final Iterator<E> it = seq.iterator();
* while (it.hasNext()) {
* final E obj = it.next();
* hashCode = 31*hashCode + (obj == null ? 0 : obj.hashCode());
* }
* [/code]
*
* @see List#hashCode()
* @see Seq#hashCode(Seq)
*
* @return the hash code value for this list
*/
@Override
public int hashCode();
/**
* Compares the specified object with this sequence for equality. Returns
* true if and only if the specified object is also a sequence, both
* sequence have the same size, and all corresponding pairs of elements in
* the two sequences are equal. (Two elements e1 and e2 are equal if
* (e1==null ? e2==null : e1.equals(e2)).) This definition ensures that the
* equals method works properly across different implementations of the Seq
* interface.
*
* @see List#equals(Object)
* @see Seq#equals(Seq, Object)
*
* @param object the object to be compared for equality with this sequence.
* @return {@code true} if the specified object is equal to this sequence,
* {@code false} otherwise.
*/
@Override
public boolean equals(final Object object);
/**
* Create a string representation of the given sequence.
*
* @param prefix the prefix of the string representation; e.g {@code '['}.
* @param separator the separator of the array elements; e.g. {@code ','}.
* @param suffix the suffix of the string representation; e.g. {@code ']'}.
* @return the string representation of this sequence.
*/
public default String toString(
final String prefix,
final String separator,
final String suffix
) {
return stream()
.map(Object::toString)
.collect(joining(separator, prefix, suffix));
}
/**
* Create a string representation of the given sequence.
*
* @param separator the separator of the array elements; e.g. {@code ','}.
* @return the string representation of this sequence.
*/
public default String toString(final String separator) {
return toString("", separator, "");
}
/**
* Unified method for calculating the hash code of every {@link Seq}
* implementation. The hash code is defined as followed:
*
* [code]
* int hashCode = 1;
* final Iterator<E> it = seq.iterator();
* while (it.hasNext()) {
* final E obj = it.next();
* hashCode = 31*hashCode + (obj == null ? 0 : obj.hashCode());
* }
* [/code]
*
* @see Seq#hashCode()
* @see List#hashCode()
*
* @param seq the sequence to calculate the hash code for.
* @return the hash code of the given sequence.
*/
public static int hashCode(final Seq seq) {
int hash = 1;
for (Object element : seq) {
hash = 31*hash + (element == null ? 0: element.hashCode());
}
return hash;
}
/**
* Unified method for compare to sequences for equality.
*
* @see Seq#equals(Object)
*
* @param seq the sequence to test for equality.
* @param obj the object to test for equality with the sequence.
* @return {@code true} if the given objects are sequences and contain the
* same objects in the same order, {@code false} otherwise.
*/
public static boolean equals(final Seq seq, final Object obj) {
if (obj == seq) {
return true;
}
if (!(obj instanceof Seq)) {
return false;
}
final Seq other = (Seq)obj;
boolean equals = (seq.length() == other.length());
for (int i = seq.length(); equals && --i >= 0;) {
final Object element = seq.get(i);
if (element != null) {
equals = element.equals(other.get(i));
} else {
equals = other.get(i) == null;
}
}
return equals;
}
/* *************************************************************************
* Some static factory methods.
* ************************************************************************/
/**
* Returns a {@code Collector} that accumulates the input elements into a
* new {@code Seq}.
*
* @param the type of the input elements
* @return a {@code Collector} which collects all the input elements into a
* {@code Seq}, in encounter order
*/
public static Collector> toSeq() {
return Collector.of(
(Supplier>)ArrayList::new,
List::add,
(left, right) -> { left.addAll(right); return left; },
Seq::of
);
}
/**
* Create a new {@code Seq} from the given values.
*
* @param the element type
* @param values the array values.
* @return a new {@code Seq} with the given values.
* @throws NullPointerException if the {@code values} array is {@code null}.
*/
@SafeVarargs
public static Seq of(final T... values) {
return ISeq.of(values);
}
/**
* Create a new {@code Seq} from the given values.
*
* @param the element type
* @param values the array values.
* @return a new {@code Seq} with the given values.
* @throws NullPointerException if the {@code values} array is {@code null}.
*/
public static Seq of(final Iterable values) {
return ISeq.of(values);
}
}