Java tutorial
/* * 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.buffer; import io.netty.util.IllegalReferenceCountException; import io.netty.util.internal.ObjectUtil; import io.netty.util.internal.StringUtil; /** * Default implementation of a {@link ByteBufHolder} that holds it's data in a {@link ByteBuf}. * */ public class DefaultByteBufHolder implements ByteBufHolder { private final ByteBuf data; public DefaultByteBufHolder(ByteBuf data) { this.data = ObjectUtil.checkNotNull(data, "data"); } @Override public ByteBuf content() { if (data.refCnt() <= 0) { throw new IllegalReferenceCountException(data.refCnt()); } return data; } /** * {@inheritDoc} * <p> * This method calls {@code replace(content().copy())} by default. */ @Override public ByteBufHolder copy() { return replace(data.copy()); } /** * {@inheritDoc} * <p> * This method calls {@code replace(content().duplicate())} by default. */ @Override public ByteBufHolder duplicate() { return replace(data.duplicate()); } /** * {@inheritDoc} * <p> * This method calls {@code replace(content().retainedDuplicate())} by default. */ @Override public ByteBufHolder retainedDuplicate() { return replace(data.retainedDuplicate()); } /** * {@inheritDoc} * <p> * Override this method to return a new instance of this object whose content is set to the specified * {@code content}. The default implementation of {@link #copy()}, {@link #duplicate()} and * {@link #retainedDuplicate()} invokes this method to create a copy. */ @Override public ByteBufHolder replace(ByteBuf content) { return new DefaultByteBufHolder(content); } @Override public int refCnt() { return data.refCnt(); } @Override public ByteBufHolder retain() { data.retain(); return this; } @Override public ByteBufHolder retain(int increment) { data.retain(increment); return this; } @Override public ByteBufHolder touch() { data.touch(); return this; } @Override public ByteBufHolder touch(Object hint) { data.touch(hint); return this; } @Override public boolean release() { return data.release(); } @Override public boolean release(int decrement) { return data.release(decrement); } /** * Return {@link ByteBuf#toString()} without checking the reference count first. This is useful to implement * {@link #toString()}. */ protected final String contentToString() { return data.toString(); } @Override public String toString() { return StringUtil.simpleClassName(this) + '(' + contentToString() + ')'; } /** * This implementation of the {@code equals} operation is restricted to * work only with instances of the same class. The reason for that is that * Netty library already has a number of classes that extend {@link DefaultByteBufHolder} and * override {@code equals} method with an additional comparison logic and we * need the symmetric property of the {@code equals} operation to be preserved. * * @param o the reference object with which to compare. * @return {@code true} if this object is the same as the obj * argument; {@code false} otherwise. */ @Override public boolean equals(Object o) { if (this == o) { return true; } if (o != null && getClass() == o.getClass()) { return data.equals(((DefaultByteBufHolder) o).data); } return false; } @Override public int hashCode() { return data.hashCode(); } }