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/*
* Copyright 2002-2024 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
*
* https://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 org.springframework.http.codec;
import java.time.Duration;
import org.springframework.lang.Nullable;
import org.springframework.util.ObjectUtils;
/**
* Representation for a Server-Sent Event for use with Spring's reactive Web support.
* {@code Flux} or {@code Observable} is the
* reactive equivalent to Spring MVC's {@code SseEmitter}.
*
* @author Sebastien Deleuze
* @author Arjen Poutsma
* @since 5.0
* @param the type of data that this event contains
* @see ServerSentEventHttpMessageWriter
* @see Server-Sent Events W3C recommendation
*/
public final class ServerSentEvent {
@Nullable
private final String id;
@Nullable
private final String event;
@Nullable
private final Duration retry;
@Nullable
private final String comment;
@Nullable
private final T data;
private ServerSentEvent(@Nullable String id, @Nullable String event, @Nullable Duration retry,
@Nullable String comment, @Nullable T data) {
this.id = id;
this.event = event;
this.retry = retry;
this.comment = comment;
this.data = data;
}
/**
* Return the {@code id} field of this event, if available.
*/
@Nullable
public String id() {
return this.id;
}
/**
* Return the {@code event} field of this event, if available.
*/
@Nullable
public String event() {
return this.event;
}
/**
* Return the {@code retry} field of this event, if available.
*/
@Nullable
public Duration retry() {
return this.retry;
}
/**
* Return the comment of this event, if available.
*/
@Nullable
public String comment() {
return this.comment;
}
/**
* Return the {@code data} field of this event, if available.
*/
@Nullable
public T data() {
return this.data;
}
@Override
public boolean equals(@Nullable Object other) {
return (this == other || (other instanceof ServerSentEvent that &&
ObjectUtils.nullSafeEquals(this.id, that.id) &&
ObjectUtils.nullSafeEquals(this.event, that.event) &&
ObjectUtils.nullSafeEquals(this.retry, that.retry) &&
ObjectUtils.nullSafeEquals(this.comment, that.comment) &&
ObjectUtils.nullSafeEquals(this.data, that.data)));
}
@Override
public int hashCode() {
return ObjectUtils.nullSafeHash(this.id, this.event, this.retry, this.comment, this.data);
}
@Override
public String toString() {
return ("ServerSentEvent [id = '" + this.id + "', event='" + this.event + "', retry=" +
this.retry + ", comment='" + this.comment + "', data=" + this.data + ']');
}
/**
* Return a builder for a {@code ServerSentEvent}.
* @param the type of data that this event contains
* @return the builder
*/
public static Builder builder() {
return new BuilderImpl<>();
}
/**
* Return a builder for a {@code ServerSentEvent}, populated with the given {@linkplain #data() data}.
* @param the type of data that this event contains
* @return the builder
*/
public static Builder builder(T data) {
return new BuilderImpl<>(data);
}
/**
* A mutable builder for a {@code ServerSentEvent}.
*
* @param the type of data that this event contains
*/
public interface Builder {
/**
* Set the value of the {@code id} field.
* @param id the value of the id field
* @return {@code this} builder
*/
Builder id(String id);
/**
* Set the value of the {@code event} field.
* @param event the value of the event field
* @return {@code this} builder
*/
Builder event(String event);
/**
* Set the value of the {@code retry} field.
* @param retry the value of the retry field
* @return {@code this} builder
*/
Builder retry(Duration retry);
/**
* Set SSE comment. If a multi-line comment is provided, it will be turned into multiple
* SSE comment lines as defined in Server-Sent Events W3C recommendation.
* @param comment the comment to set
* @return {@code this} builder
*/
Builder comment(String comment);
/**
* Set the value of the {@code data} field. If the {@code data} argument is a multi-line
* {@code String}, it will be turned into multiple {@code data} field lines as defined
* in the Server-Sent Events W3C recommendation. If {@code data} is not a String, it will
* be {@linkplain org.springframework.http.codec.json.Jackson2JsonEncoder encoded} into JSON.
* @param data the value of the data field
* @return {@code this} builder
*/
Builder data(@Nullable T data);
/**
* Builds the event.
* @return the built event
*/
ServerSentEvent build();
}
private static class BuilderImpl implements Builder {
@Nullable
private String id;
@Nullable
private String event;
@Nullable
private Duration retry;
@Nullable
private String comment;
@Nullable
private T data;
public BuilderImpl() {
}
public BuilderImpl(T data) {
this.data = data;
}
@Override
public Builder id(String id) {
this.id = id;
return this;
}
@Override
public Builder event(String event) {
this.event = event;
return this;
}
@Override
public Builder retry(Duration retry) {
this.retry = retry;
return this;
}
@Override
public Builder comment(String comment) {
this.comment = comment;
return this;
}
@Override
public Builder data(@Nullable T data) {
this.data = data;
return this;
}
@Override
public ServerSentEvent build() {
return new ServerSentEvent<>(this.id, this.event, this.retry, this.comment, this.data);
}
}
}