/*
* Copyright 2008 - 2009 Lars Heuer (heuer[at]semagia.com). All rights reserved.
*
* 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 com.semagia.atomico.server.impl.jaxrs;
import java.util.Date;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.Request;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.Response.ResponseBuilder;
import com.semagia.atomico.server.IConfiguration;
import com.semagia.atomico.server.IServerApplication;
import com.semagia.atomico.server.ServerApplicationProvider;
import com.semagia.atomico.server.storage.IModifiableStorage;
import com.semagia.atomico.server.storage.IStorage;
/**
* Abstract base class for all resources.
*
* Provides mainly access to the underlying storage and configuration.
*
* @author Lars Heuer (heuer[at]semagia.com) <a href="http://www.semagia.com/">Semagia</a>
*/
abstract class AbstractBaseResource {
protected final Request _request;
private final IServerApplication _app;
AbstractBaseResource(final Request request) {
_request = request;
_app = ServerApplicationProvider.getServerApplication();
if (_app == null) {
throw new WebApplicationException(Response.Status.INTERNAL_SERVER_ERROR);
}
}
/**
* Returns the time when the resource was modified.
* <p>
* This method is invoked by {@link #makeResponseBuilder()} and this property
* may be state-dependent.
* </p>
*
* @return The time when this resource was modified.
*/
protected abstract long lastModification();
/**
* Creates a {@link ResponseBuilder} with a last-modified header.
*
* If the request contains a <tt>If-Modified-Since</tt> header and the
* resource wasn't modified, a {@link WebApplicationException} with
* the status <tt>Not modified (304)</tt> is thrown.
*
* @return A response builder.
* @throws WebApplicationException In case the resource wasn't modified.
*/
protected ResponseBuilder makeResponseBuilder() throws WebApplicationException {
final Date lastModification = new Date(lastModification());
ResponseBuilder builder = _request.evaluatePreconditions(lastModification);
if (builder != null) {
// Preconditions are met, report the status to the client
throw new WebApplicationException(builder.build());
}
builder = Response.ok();
builder.lastModified(lastModification);
return builder;
}
/**
* Returns the configuration instance.
*
* @return The configuration.
*/
protected IConfiguration getConfiguration() {
return _app.getConfiguration();
}
/**
* Returns the underlying storage.
*
* @return The storage instance to operate upon, never <tt>null</tt>.
*/
protected IStorage getStorage() {
return _app.getStorage();
}
/**
* Returns either an {@link IModifiableStorage}
*
* @return A {@link IModifiableStorage}.
* @throws WebApplicationException If the storage is not modifiable.
*/
protected IModifiableStorage getModifiableStorage() throws WebApplicationException {
final IStorage storage = getStorage();
if (!storage.isModifiable()) {
throw new WebApplicationException(ResponseUtils.methodNotAllowed());
}
return (IModifiableStorage) storage;
}
}