| /* |
| * Copyright 2010 Google Inc. |
| * |
| * 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.google.gwt.requestfactory.client.impl; |
| |
| import com.google.gwt.requestfactory.shared.EntityProxy; |
| import com.google.gwt.requestfactory.shared.EntityProxyId; |
| |
| /** |
| * Nothing fancy. |
| * |
| * @param <P> the type of EntityProxy object the id describes |
| */ |
| public class SimpleEntityProxyId<P extends EntityProxy> implements |
| EntityProxyId<P> { |
| /** |
| * A placeholder value for {@link #clientId} to indicate the id was not |
| * created locally. |
| */ |
| private static final int NEVER_EPHEMERAL = -1; |
| |
| /** |
| * The client-side id is ephemeral, and is valid only during the lifetime of a |
| * module. Any use of the client-side id except to send to the server as a |
| * bookkeeping exercise is wrong. |
| */ |
| private final int clientId; |
| |
| /** |
| * The hashcode of the id must remain stable, even if the server id is later |
| * assigned. |
| */ |
| private final int hashCode; |
| |
| private final Class<P> proxyClass; |
| |
| /** |
| * The serverId is totally opaque to the client. It's probably a |
| * base64-encoded string, but it could be digits of pi. Any code that does |
| * anything other than send the contents of this field back to the server is |
| * wrong. |
| */ |
| private String serverId; |
| |
| /** |
| * Construct a stable id. May only be called from |
| * {@link AbstractRequestFactory#getId}. |
| */ |
| SimpleEntityProxyId(Class<P> proxyClass, String serverId) { |
| setServerId(serverId); |
| clientId = NEVER_EPHEMERAL; |
| hashCode = serverId.hashCode(); |
| this.proxyClass = proxyClass; |
| } |
| |
| /** |
| * Construct an ephemeral id. May be called only from |
| * {@link AbstractRequestFactory#allocateId}. |
| */ |
| SimpleEntityProxyId(Class<P> proxyClass, int clientId) { |
| this.clientId = clientId; |
| this.proxyClass = proxyClass; |
| hashCode = clientId; |
| } |
| |
| public boolean equals(Object o) { |
| if (this == o) { |
| return true; |
| } |
| if (!(o instanceof SimpleEntityProxyId<?>)) { |
| return false; |
| } |
| SimpleEntityProxyId<?> other = (SimpleEntityProxyId<?>) o; |
| if (!proxyClass.equals(other.proxyClass)) { |
| return false; |
| } |
| |
| if (clientId != NEVER_EPHEMERAL && clientId == other.clientId) { |
| /* |
| * Unexpected: It should be the case that locally-created ids are never |
| * aliased and will be caught by the first if statement. |
| */ |
| return true; |
| } |
| |
| if (serverId != null && serverId.equals(other.serverId)) { |
| return true; |
| } |
| return false; |
| } |
| |
| public int getClientId() { |
| return clientId; |
| } |
| |
| public Class<P> getProxyClass() { |
| return proxyClass; |
| } |
| |
| public String getServerId() { |
| return serverId; |
| } |
| |
| public int hashCode() { |
| return hashCode; |
| } |
| |
| public boolean isEphemeral() { |
| return serverId == null; |
| } |
| |
| /** |
| * Allows the server id token to be set. This method may be called exactly |
| * once over the lifetime of an id. |
| */ |
| public void setServerId(String serverId) { |
| if (this.serverId != null) { |
| throw new IllegalStateException(); |
| } |
| this.serverId = serverId; |
| } |
| } |