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Objectos Way allows you to build full-stack web applications using only Java.
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/*
* Copyright (C) 2022-2023 Objectos Software LTDA.
*
* 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 objectos.way;
import java.util.Arrays;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Objects;
/**
* This class provides {@code static} utility methods for {@link java.util.List}
* classes and objects.
*/
final class UtilLists {
static class SimpleIterator extends Util.UnmodifiableIterator {
private final Object[] data;
private final int size;
private int index;
public SimpleIterator(Object[] data, int size) {
this.data = data;
this.size = size;
}
@Override
public final boolean hasNext() {
return index < size;
}
@SuppressWarnings("unchecked")
@Override
public final E next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
else {
var result = data[index];
index++;
return (E) result;
}
}
}
private UtilLists() {}
/**
* Returns the only element of the specified list or throws an exception if
* the list is empty or if the list contains more than one element.
*
* @param
* the class of the objects in the list
* @param list
* the list whose only element is to be returned
*
* @return the only element of this list
*
* @throws IllegalStateException
* if the list is empty or if the list contains more than one element
*/
public static T getOnly(List list) {
switch (list.size()) {
case 0:
throw new IllegalStateException("Could not getOnly: empty.");
case 1:
return list.get(0);
default:
throw new IllegalStateException("Could not getOnly: more than one element.");
}
}
static boolean containsImpl(Object[] data, int size, Object o) {
if (o == null) {
return false;
}
for (int i = 0; i < size; i++) {
var thisElem = data[i];
if (thisElem.equals(o)) {
return true;
}
}
return false;
}
static boolean equals0(List self, List that) {
var size = self.size();
if (size != that.size()) {
return false;
}
for (int i = 0; i < size; i++) {
var e = self.get(i);
var o = that.get(i);
// e is guaranteed to be not null
if (!e.equals(o)) {
return false;
}
}
return true;
}
static boolean equalsImpl(List self, Object obj) {
return obj == self
|| obj instanceof List that && equals0(self, that);
}
static Object getImpl(Object[] data, int size, int index) {
Objects.checkIndex(index, size);
return data[index];
}
static int hashCodeImpl(Object[] data, int size) {
var hashCode = 1;
for (int i = 0; i < size; i++) {
var e = data[i];
// e is guaranteed to be not null
hashCode = 31 * hashCode + e.hashCode();
}
return hashCode;
}
static int indexOfImpl(Object[] data, int size, Object o) {
var result = -1;
if (o == null) {
return result;
}
for (int i = 0; i < size; i++) {
var element = data[i];
if (element.equals(o)) {
result = i;
break;
}
}
return result;
}
static String joinImpl(Object[] data, int size) {
if (size == 0) {
return "";
}
if (size == 1) {
var o = data[0];
return o.toString();
}
var sb = new StringBuilder();
for (int i = 0; i < size; i++) {
sb.append(data[i]);
}
return sb.toString();
}
static String joinImpl(Object[] data, int size, String delimiter) {
Check.notNull(delimiter, "delimiter == null");
if (size == 0) {
return "";
}
Object o;
if (size == 1) {
o = data[0];
return o.toString();
}
StringBuilder sb;
sb = new StringBuilder();
o = data[0];
sb.append(o.toString());
for (int i = 1; i < size; i++) {
sb.append(delimiter);
o = data[i];
sb.append(o.toString());
}
return sb.toString();
}
static String joinImpl(Object[] data, int size, String delimiter, String prefix, String suffix) {
Check.notNull(delimiter, "delimiter == null");
Check.notNull(prefix, "prefix == null");
Check.notNull(suffix, "suffix == null");
if (size == 0) {
return prefix + suffix;
}
Object o;
if (size == 1) {
o = data[0];
return prefix + o.toString() + suffix;
}
var sb = new StringBuilder();
sb.append(prefix);
o = data[0];
sb.append(o.toString());
for (int i = 1; i < size; i++) {
sb.append(delimiter);
o = data[i];
sb.append(o.toString());
}
sb.append(suffix);
return sb.toString();
}
static int lastIndexOfImpl(Object[] data, int size, Object o) {
var result = -1;
for (int i = size - 1; i >= 0; i--) {
var element = data[i];
if (element.equals(o)) {
result = i;
break;
}
}
return result;
}
@SuppressWarnings("unchecked")
static T[] toArrayImpl(Object[] data, int size, T[] a) {
Check.notNull(a, "a == null");
if (a.length < size) {
Class newType;
newType = a.getClass();
Object[] copy;
copy = Arrays.copyOf(data, size, newType);
return (T[]) copy;
}
System.arraycopy(data, 0, a, 0, size);
if (a.length > size) {
a[size] = null;
}
return a;
}
static String toStringImpl(Object self, Object[] data, int size) {
if (size == 0) {
return "[]";
}
StringBuilder sb;
sb = new StringBuilder();
sb.append('[');
for (int idx = 0; idx < size; idx++) {
if (idx > 0) {
sb.append(',');
sb.append(' ');
}
Object o;
o = data[idx];
if (o == self) {
sb.append("(this Collection)");
} else {
sb.append(o);
}
}
sb.append(']');
return sb.toString();
}
}