AbstractWebSocketMessage.java

/*
 * Copyright 2002-2014 the original author or authors.
 *
 * 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 ameba.websocket;


import ameba.util.Assert;

import java.util.Objects;

/**
 * A message that can be handled or sent on a WebSocket connection.
 *
 * @author Rossen Stoyanchev
 * @author icode
 *
 */
public abstract class AbstractWebSocketMessage<T> implements WebSocketMessage<T> {

    private final T payload;

    private final boolean last;


    /**
     * Create a new WebSocket message with the given payload.
     *
     * @param payload the non-null payload
     */
    AbstractWebSocketMessage(T payload) {
        this(payload, true);
    }

    /**
     * Create a new WebSocket message given payload representing the full or partial
     * message content. When the {@code isLast} boolean flag is set to {@code false}
     * the message is sent as partial content and more partial messages will be
     * expected until the boolean flag is set to {@code true}.
     *
     * @param payload the non-null payload
     * @param isLast  if the message is the last of a series of partial messages
     */
    AbstractWebSocketMessage(T payload, boolean isLast) {
        Assert.notNull(payload, "payload must not be null");
        this.payload = payload;
        this.last = isLast;
    }


    /**
     * Return the message payload, never be {@code null}.
     *
     * @return a T object.
     */
    public T getPayload() {
        return this.payload;
    }

    /**
     * Whether this is the last part of a message sent as a series of partial messages.
     *
     * @return a boolean.
     */
    public boolean isLast() {
        return this.last;
    }


    /**
     * {@inheritDoc}
     */
    @Override
    public boolean equals(Object other) {
        if (this == other) {
            return true;
        }
        if (!(other instanceof AbstractWebSocketMessage)) {
            return false;
        }
        AbstractWebSocketMessage<?> otherMessage = (AbstractWebSocketMessage<?>) other;
        return Objects.deepEquals(this.payload, otherMessage.payload);
    }

    /** {@inheritDoc} */
    @Override
    public int hashCode() {
        return Objects.hashCode(this.payload);
    }

    /** {@inheritDoc} */
    @Override
    public String toString() {
        return getClass().getSimpleName() + " payload=[" + toStringPayload() +
                "], byteCount=" + getPayloadLength() + ", last=" + isLast() + "]";
    }

    /**
     * <p>toStringPayload.</p>
     *
     * @return a {@link java.lang.String} object.
     */
    protected abstract String toStringPayload();

}