/*
* Copyright 2013 The Netty Project
*
* The Netty Project licenses this file to you 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 io.netty.util.internal;
import io.netty.util.Recycler;
import io.netty.util.Recycler.Handle;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.RandomAccess;
/**
* A simple list which is reyclable. This implementation does not allow {@code null} elements to be added.
*/
public final class RecyclableArrayList extends ArrayList<Object> {
private static final long serialVersionUID = -8605125654176467947L;
private static final int DEFAULT_INITIAL_CAPACITY = 8;
private static final Recycler<RecyclableArrayList> RECYCLER = new Recycler<RecyclableArrayList>() {
@Override
protected RecyclableArrayList newObject(Handle handle) {
return new RecyclableArrayList(handle);
}
};
/**
* Create a new empty {@link RecyclableArrayList} instance
*/
public static RecyclableArrayList newInstance() {
return newInstance(DEFAULT_INITIAL_CAPACITY);
}
/**
* Create a new empty {@link RecyclableArrayList} instance with the given capacity.
*/
public static RecyclableArrayList newInstance(int minCapacity) {
RecyclableArrayList ret = RECYCLER.get();
ret.ensureCapacity(minCapacity);
return ret;
}
private final Handle handle;
private RecyclableArrayList(Handle handle) {
this(handle, DEFAULT_INITIAL_CAPACITY);
}
private RecyclableArrayList(Handle handle, int initialCapacity) {
super(initialCapacity);
this.handle = handle;
}
@Override
public boolean addAll(Collection<?> c) {
checkNullElements(c);
return super.addAll(c);
}
@Override
public boolean addAll(int index, Collection<?> c) {
checkNullElements(c);
return super.addAll(index, c);
}
private static void checkNullElements(Collection<?> c) {
if (c instanceof RandomAccess && c instanceof List) {
// produce less garbage
List<?> list = (List<?>) c;
int size = list.size();
for (int i = 0; i < size; i++) {
if (list.get(i) == null) {
throw new IllegalArgumentException("c contains null values");
}
}
} else {
for (Object element: c) {
if (element == null) {
throw new IllegalArgumentException("c contains null values");
}
}
}
}
@Override
public boolean add(Object element) {
if (element == null) {
throw new NullPointerException("element");
}
return super.add(element);
}
@Override
public void add(int index, Object element) {
if (element == null) {
throw new NullPointerException("element");
}
super.add(index, element);
}
@Override
public Object set(int index, Object element) {
if (element == null) {
throw new NullPointerException("element");
}
return super.set(index, element);
}
/**
* Clear and recycle this instance.
*/
public boolean recycle() {
clear();
return RECYCLER.recycle(this, handle);
}
}