// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// https://developers.google.com/protocol-buffers/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
package com.google.protobuf;
import com.google.protobuf.
Internal.
ProtobufList;
import java.util.
AbstractList;
import java.util.
Collection;
import java.util.
List;
import java.util.
RandomAccess;
/**
* An abstract implementation of {@link ProtobufList} which manages mutability semantics. All mutate
* methods must check if the list is mutable before proceeding. Subclasses must invoke
* {@link #ensureIsMutable()} manually when overriding those methods.
* <p>
* This implementation assumes all subclasses are array based, supporting random access.
*/
abstract class
AbstractProtobufList<E> extends
AbstractList<E> implements
ProtobufList<E> {
protected static final int
DEFAULT_CAPACITY = 10;
/**
* Whether or not this list is modifiable.
*/
private boolean
isMutable;
/**
* Constructs a mutable list by default.
*/
AbstractProtobufList() {
isMutable = true;
}
@
Override
public boolean
equals(
Object o) {
if (
o == this) {
return true;
}
if (!(
o instanceof
List)) {
return false;
}
// Handle lists that do not support RandomAccess as efficiently as possible by using an iterator
// based approach in our super class. Otherwise our index based approach will avoid those
// allocations.
if (!(
o instanceof
RandomAccess)) {
return super.equals(
o);
}
List<?>
other = (
List<?>)
o;
final int
size =
size();
if (
size !=
other.
size()) {
return false;
}
for (int
i = 0;
i <
size;
i++) {
if (!
get(
i).
equals(
other.
get(
i))) {
return false;
}
}
return true;
}
@
Override
public int
hashCode() {
final int
size =
size();
int
hashCode = 1;
for (int
i = 0;
i <
size;
i++) {
hashCode = (31 *
hashCode) +
get(
i).
hashCode();
}
return
hashCode;
}
@
Override
public boolean
add(E
e) {
ensureIsMutable();
return super.add(
e);
}
@
Override
public void
add(int
index, E
element) {
ensureIsMutable();
super.add(
index,
element);
}
@
Override
public boolean
addAll(
Collection<? extends E>
c) {
ensureIsMutable();
return super.addAll(
c);
}
@
Override
public boolean
addAll(int
index,
Collection<? extends E>
c) {
ensureIsMutable();
return super.addAll(
index,
c);
}
@
Override
public void
clear() {
ensureIsMutable();
super.clear();
}
@
Override
public boolean
isModifiable() {
return
isMutable;
}
@
Override
public final void
makeImmutable() {
isMutable = false;
}
@
Override
public E
remove(int
index) {
ensureIsMutable();
return super.remove(
index);
}
@
Override
public boolean
remove(
Object o) {
ensureIsMutable();
return super.remove(
o);
}
@
Override
public boolean
removeAll(
Collection<?>
c) {
ensureIsMutable();
return super.removeAll(
c);
}
@
Override
public boolean
retainAll(
Collection<?>
c) {
ensureIsMutable();
return super.retainAll(
c);
}
@
Override
public E
set(int
index, E
element) {
ensureIsMutable();
return super.set(
index,
element);
}
/**
* Throws an {@link UnsupportedOperationException} if the list is immutable. Subclasses are
* responsible for invoking this method on mutate operations.
*/
protected void
ensureIsMutable() {
if (!
isMutable) {
throw new
UnsupportedOperationException();
}
}
}