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Small improvements to ListModelJavaList
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@jwharm
jwharm committed Dec 24, 2024
1 parent b7c09ab commit d2b3d6c
Showing 1 changed file with 100 additions and 36 deletions.
136 changes: 100 additions & 36 deletions modules/gio/src/main/java/io/github/jwharm/javagi/gio/ListModelJavaList.java
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/* Java-GI - Java language bindings for GObject-Introspection-based libraries
* Copyright (C) 2022-2023 Jan-Willem Harmannij
* Copyright (C) 2022-2024 Jan-Willem Harmannij
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*
Expand All @@ -24,16 +24,25 @@
import org.jetbrains.annotations.NotNull;

import java.lang.reflect.Array;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
import java.util.*;

/**
* This interface is implemented by {@link ListModel}, so it can be used like a
* regular Java {@link List}. The list is immutable, so all mutations such as
* {@link #add}, {@link #set} and {@link #remove} throw
* {@link UnsupportedOperationException}.
* regular Java {@link List}.
* <p>
* Because {@code ListModel} only defines operations to retrieve items and
* size, the default implementations of the {@code List} mutator methods
* throw {@code UnsupportedOperationException}. ListModel implementations that
* support mutation must override the following methods:
* <ul>
* <li>{@link #set(int, E)}
* <li>{@link #add(E)}
* <li>{@link #add(int, E)}
* <li>{@link #remove(int)}
* <li>{@link #remove(Object)}
* </ul>
* It is recommended to also override other operations such as {@link #clear()}
* with a more efficient implementation.
*
* @param <E> The item type must be a GObject.
*/
Expand All @@ -45,7 +54,8 @@ public interface ListModelJavaList<E extends GObject> extends List<E> {
/**
* {@inheritDoc}
*
* @apiNote This operation is implemented with {@link ListModel#getNItems()}
* @apiNote This operation is implemented with
* {@link ListModel#getNItems()}.
*/
@Override
default int size() {
Expand All @@ -54,6 +64,9 @@ default int size() {

/**
* {@inheritDoc}
*
* @apiNote This operation is implemented by checking if {@link #size}
* returns 0.
*/
@Override
default boolean isEmpty() {
Expand All @@ -79,16 +92,14 @@ default boolean contains(Object o) {
/**
* {@inheritDoc}
*/
@NotNull
@Override
default Iterator<E> iterator() {
default @NotNull Iterator<E> iterator() {
return listIterator();
}

/**
* {@inheritDoc}
*/
@NotNull
@Override
default Object @NotNull [] toArray() {
return toArray(new Object[0]);
Expand All @@ -97,10 +108,9 @@ default Iterator<E> iterator() {
/**
* {@inheritDoc}
*/
@NotNull
@Override
@SuppressWarnings("unchecked") // Unchecked casts are unavoidable here
default <T> T @NotNull [] toArray(@NotNull T @NotNull [] a) {
default <T> T @NotNull [] toArray(T @NotNull [] a) {
int size = size();
T[] data = a.length >= size ? a :
(T[]) Array.newInstance(a.getClass().getComponentType(), size);
Expand Down Expand Up @@ -132,6 +142,10 @@ default boolean remove(Object o) {

/**
* {@inheritDoc}
*
* @apiNote This operation is implemented by calling
* {@link #contains(Object)} for all elements in the specified
* collection.
*/
@Override
default boolean containsAll(@NotNull Collection<?> c) {
Expand All @@ -142,43 +156,80 @@ default boolean containsAll(@NotNull Collection<?> c) {
}

/**
* Always throws {@link UnsupportedOperationException}.
* {@inheritDoc}
*
* @apiNote This operation is implemented by calling {@link #add(E)}
* for all elements in the specified collection.
*/
@Override
default boolean addAll(@NotNull Collection<? extends E> c) {
throw new UnsupportedOperationException();
boolean changed = false;
for (E item : c) {
add(item);
changed = true;
}
return changed;
}

/**
* Always throws {@link UnsupportedOperationException}.
* {@inheritDoc}
*
* @apiNote This operation is implemented by calling {@link #add(int, E)}
* for all elements in the specified collection.
*/
@Override
default boolean addAll(int index, @NotNull Collection<? extends E> c) {
throw new UnsupportedOperationException();
boolean changed = false;
for (E item : c) {
add(index++, item);
changed = true;
}
return changed;
}

/**
* Always throws {@link UnsupportedOperationException}.
* {@inheritDoc}
*
* @apiNote This operation is implemented with {@link #remove(Object)} for
* all elements that are in the specified collection.
*/
@Override
default boolean removeAll(@NotNull Collection<?> c) {
throw new UnsupportedOperationException();
boolean changed = false;
for (Object item : c) {
if (remove(item))
changed = true;
}
return changed;
}

/**
* Always throws {@link UnsupportedOperationException}.
* {@inheritDoc}
*
* @apiNote This operation is implemented with {@link #remove(Object)} for
* all elements that are not in the specified collection.
*/
@Override
default boolean retainAll(@NotNull Collection<?> c) {
throw new UnsupportedOperationException();
boolean changed = false;
for (E item : this) {
if (!c.contains(item))
changed = remove(item);
}
return changed;
}

/**
* Always throws {@link UnsupportedOperationException}.
* {@inheritDoc}
*
* @apiNote This operation is implemented by repeatedly calling
* {@link #remove(int)} until the list is empty.
*/
@Override
default void clear() {
throw new UnsupportedOperationException();
int size = size();
for (int i = 0; i < size; i++)
remove(0);
}

/**
Expand Down Expand Up @@ -248,20 +299,19 @@ default int lastIndexOf(Object o) {
/**
* {@inheritDoc}
*/
@NotNull
@Override
default ListIterator<E> listIterator() {
default @NotNull ListIterator<E> listIterator() {
return listIterator(0);
}

/**
* {@inheritDoc}
*/
@NotNull
@Override
default ListIterator<E> listIterator(int index) {
default @NotNull ListIterator<E> listIterator(int index) {
return new ListIterator<>() {
int next = index;
int next = index; // Index of the next element to be returned
int last = -1; // Index of the last returned element

@Override
public boolean hasNext() {
Expand All @@ -270,6 +320,9 @@ public boolean hasNext() {

@Override
public E next() {
if (!hasNext())
throw new NoSuchElementException();
last = next;
return get(next++);
}

Expand All @@ -280,7 +333,10 @@ public boolean hasPrevious() {

@Override
public E previous() {
return get(--next);
if (!hasPrevious())
throw new NoSuchElementException();
last = --next;
return get(last);
}

@Override
Expand All @@ -295,28 +351,36 @@ public int previousIndex() {

@Override
public void remove() {
throw new UnsupportedOperationException();
if (last < 0)
throw new IllegalStateException();
ListModelJavaList.this.remove(last);
if (last < next) // Adjust 'next' if remove was before it
next--;
last = -1; // Reset 'last'
}

@Override
public void set(E e) {
throw new UnsupportedOperationException();
if (last < 0)
throw new IllegalStateException();
ListModelJavaList.this.set(last, e);
}

@Override
public void add(E e) {
throw new UnsupportedOperationException();
ListModelJavaList.this.add(next, e);
next++; // Adjust 'next' to reflect the added element
last = -1; // Reset 'last'
}
};
}

/**
* {@inheritDoc}
*/
@NotNull
@Override
default List<E> subList(int fromIndex, int toIndex) {
if (fromIndex < 0 || toIndex > size() || fromIndex > toIndex)
default @NotNull List<E> subList(int fromIndex, int toIndex) {
if (fromIndex < 0 || fromIndex > toIndex || toIndex > size())
throw new IndexOutOfBoundsException();

return new ListModelJavaList<>() {
Expand Down

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