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/*
* Copyright 2007-2008, Josh Devins.
*
* 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 org.mattressframework.api.http;
import org.apache.commons.lang.Validate;
/**
* A simple model encapsulating elements of an HTTP response.
*
*
* This does not include any entity, since that is handled by the return value
* of a resource method. This differs greatly from JSR 311 which specifies that
* a resource method can return a Response. Not allowing this is much more
* pragmatic since it follows a rule that any entity to be returned in a
* response must also be returned from the resource method. No exceptions to the
* rule. End of story.
*
*
*
* To build the other elements of an HTTP response, an instance of
* {@link Response} can be injected into a resource method. Instances are
* semi-immutable since the Response must be instantiated to be passed by
* reference to the resource method. Once instantiated however, the setter
* methods can only be called once, or else an {@link IllegalStateException}
* will be thrown. Using the constructor will create an immutable instance,
* although this is only done by the framework.
*
*
*
* If setting the header fields manually, take care to only set headers that
* pertain to the response, and not to the entity since those will be set by the
* framework if needed. If entity header fields are added manually, the
* framework may override them.
* TODO: More information about what headers can be overriden by the framework.
*
*
*
* - RFC 2616 (HTTP/1.1), Section
* 6.2 Response Header Fields
*
*
* @author Josh Devins ([email protected])
*/
public final class Response {
private int status = -1;
private Header[] headers = null;
/**
* Default constructor. Setter methods can be called once after
* instantiating this way.
*/
public Response() {
// defaults already set
}
/**
* Creates an immutable instance of this class. Internally calls
* {@link #setStatus(int)} and {@link #setHeaders(Header[])}. Sets the
* headers to an empty array.
*/
public Response(final int status) {
setStatus(status);
setHeaders(new Header[0]);
}
/**
* Creates an immutable instance of this class. Internally calls
* {@link #setStatus(int)} and {@link #setHeaders(Header[])}.
*/
public Response(final int status, final Header... headers) {
setStatus(status);
setHeaders(headers);
}
public Header[] getHeaders() {
return headers;
}
public int getStatus() {
return status;
}
/**
* Sets the headers to be sent back with the response. This can only be
* called once.
*
* @throws IllegalArgumentException
* Thrown if the headers being set contain or are themselves
* null.
* @throws IllegalStateException
* Thrown if this method is called more than once.
*/
public void setHeaders(final Header... headers) {
Validate.noNullElements(headers);
if (this.headers != null) {
throw new IllegalStateException("Headers have already been set.");
}
this.headers = headers;
}
/**
* Sets the status to be sent back with the response. This can only be
* called once.
*
* @throws IllegalArgumentException
* Thrown if the status being set is not greater than or equal
* to 0.
* @throws IllegalStateException
* Thrown if this method is called more than once.
*/
public void setStatus(final int status) {
Validate.isTrue(status >= 0);
if (this.status != -1) {
throw new IllegalStateException("Status has already been set.");
}
this.status = status;
}
}