org.springframework.web.reactive.HandlerResult Maven / Gradle / Ivy
/*
* Copyright 2002-2017 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.web.reactive;
import java.util.function.Function;
import reactor.core.publisher.Mono;
import org.springframework.core.MethodParameter;
import org.springframework.core.ResolvableType;
import org.springframework.lang.Nullable;
import org.springframework.ui.Model;
import org.springframework.util.Assert;
/**
* Represent the result of the invocation of a handler or a handler method.
*
* @author Rossen Stoyanchev
* @since 5.0
*/
public class HandlerResult {
private final Object handler;
@Nullable
private final Object returnValue;
private final ResolvableType returnType;
private final BindingContext bindingContext;
@Nullable
private Function> exceptionHandler;
/**
* Create a new {@code HandlerResult}.
* @param handler the handler that handled the request
* @param returnValue the return value from the handler possibly {@code null}
* @param returnType the return value type
*/
public HandlerResult(Object handler, @Nullable Object returnValue, MethodParameter returnType) {
this(handler, returnValue, returnType, null);
}
/**
* Create a new {@code HandlerResult}.
* @param handler the handler that handled the request
* @param returnValue the return value from the handler possibly {@code null}
* @param returnType the return value type
* @param context the binding context used for request handling
*/
public HandlerResult(Object handler, @Nullable Object returnValue, MethodParameter returnType,
@Nullable BindingContext context) {
Assert.notNull(handler, "'handler' is required");
Assert.notNull(returnType, "'returnType' is required");
this.handler = handler;
this.returnValue = returnValue;
this.returnType = ResolvableType.forMethodParameter(returnType);
this.bindingContext = (context != null ? context : new BindingContext());
}
/**
* Return the handler that handled the request.
*/
public Object getHandler() {
return this.handler;
}
/**
* Return the value returned from the handler, if any.
*/
@Nullable
public Object getReturnValue() {
return this.returnValue;
}
/**
* Return the type of the value returned from the handler -- e.g. the return
* type declared on a controller method's signature. Also see
* {@link #getReturnTypeSource()} to obtain the underlying
* {@link MethodParameter} for the return type.
*/
public ResolvableType getReturnType() {
return this.returnType;
}
/**
* Return the {@link MethodParameter} from which {@link #getReturnType()
* returnType} was created.
*/
public MethodParameter getReturnTypeSource() {
return (MethodParameter) this.returnType.getSource();
}
/**
* Return the BindingContext used for request handling.
*/
public BindingContext getBindingContext() {
return this.bindingContext;
}
/**
* Return the model used for request handling. This is a shortcut for
* {@code getBindingContext().getModel()}.
*/
public Model getModel() {
return this.bindingContext.getModel();
}
/**
* Configure an exception handler that may be used to produce an alternative
* result when result handling fails. Especially for an async return value
* errors may occur after the invocation of the handler.
* @param function the error handler
* @return the current instance
*/
public HandlerResult setExceptionHandler(Function> function) {
this.exceptionHandler = function;
return this;
}
/**
* Whether there is an exception handler.
*/
public boolean hasExceptionHandler() {
return (this.exceptionHandler != null);
}
/**
* Apply the exception handler and return the alternative result.
* @param failure the exception
* @return the new result or the same error if there is no exception handler
*/
public Mono applyExceptionHandler(Throwable failure) {
return (this.exceptionHandler != null ? this.exceptionHandler.apply(failure) : Mono.error(failure));
}
}