| /* |
| * 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.web.bindery.requestfactory.shared.impl; |
| |
| import com.google.web.bindery.requestfactory.shared.BaseProxy; |
| |
| /** |
| * The base implementation of id objects in the RequestFactory system. This type |
| * exists to allow ValueProxies to be implemented in the same manner as an |
| * EntityProxy as far as metadata maintenance is concerned. There is a specific |
| * subtype {@link SimpleEntityProxyId} which implements the requisite public |
| * interface for EntityProxy types. |
| * |
| * @param <P> the type of BaseProxy object the id describes |
| */ |
| public class SimpleProxyId<P extends BaseProxy> { |
| /** |
| * A placeholder value for {@link #clientId} to indicate the id was not |
| * created locally. |
| */ |
| public 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 encodedAddress 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 encodedAddress; |
| |
| /** |
| * The hashcode of the id must remain stable, even if the server id is later |
| * assigned. |
| */ |
| private final int hashCode; |
| |
| /** |
| * The EntityProxy type. |
| */ |
| private final Class<P> proxyClass; |
| |
| /** |
| * A flag to indicate that the id is synthetic, that it is not valid beyond |
| * the duration of the request. |
| */ |
| private int syntheticId; |
| |
| /** |
| * Construct an ephemeral id. May be called only from |
| * {@link IdFactory#createId()}. |
| */ |
| SimpleProxyId(Class<P> proxyClass, int clientId) { |
| assert proxyClass != null; |
| this.clientId = clientId; |
| this.proxyClass = proxyClass; |
| hashCode = clientId; |
| } |
| |
| /** |
| * Construct a stable id. May only be called from {@link IdFactory#createId()} |
| */ |
| SimpleProxyId(Class<P> proxyClass, String encodedAddress) { |
| assert proxyClass != null; |
| assert encodedAddress != null; |
| setServerId(encodedAddress); |
| clientId = NEVER_EPHEMERAL; |
| hashCode = encodedAddress.hashCode(); |
| this.proxyClass = proxyClass; |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (this == o) { |
| return true; |
| } |
| if (!(o instanceof SimpleProxyId<?>)) { |
| return false; |
| } |
| SimpleProxyId<?> other = (SimpleProxyId<?>) 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 (encodedAddress != null && encodedAddress.equals(other.encodedAddress)) { |
| return true; |
| } |
| return false; |
| } |
| |
| public int getClientId() { |
| return clientId; |
| } |
| |
| public Class<P> getProxyClass() { |
| return proxyClass; |
| } |
| |
| /** |
| * TODO: Rename to getAddress(). |
| */ |
| public String getServerId() { |
| return encodedAddress; |
| } |
| |
| /** |
| * A flag to indicate that the id is synthetic, that it is not valid beyond |
| * the duration of the request. |
| */ |
| public int getSyntheticId() { |
| return syntheticId; |
| } |
| |
| @Override |
| public int hashCode() { |
| return hashCode; |
| } |
| |
| public boolean isEphemeral() { |
| return encodedAddress == null; |
| } |
| |
| public boolean isSynthetic() { |
| return syntheticId > 0; |
| } |
| |
| /** |
| * Allows the server address token to be set. This method may be called |
| * exactly once over the lifetime of an id. |
| */ |
| public void setServerId(String encodedAddress) { |
| if (this.encodedAddress != null) { |
| throw new IllegalStateException(); |
| } |
| assert !"null".equals(encodedAddress); |
| this.encodedAddress = encodedAddress; |
| } |
| |
| public void setSyntheticId(int syntheticId) { |
| this.syntheticId = syntheticId; |
| } |
| |
| /** |
| * For debugging use only. |
| */ |
| @Override |
| public String toString() { |
| if (isEphemeral()) { |
| return IdUtil.ephemeralId(clientId, proxyClass.getName()); |
| } else if (isSynthetic()) { |
| return IdUtil.syntheticId(syntheticId, proxyClass.getName()); |
| } else { |
| return IdUtil.persistedId(encodedAddress, proxyClass.getName()); |
| } |
| } |
| |
| /** |
| * Returns <code>true</code> if the id was created as an ephemeral id. |
| */ |
| public boolean wasEphemeral() { |
| return clientId != NEVER_EPHEMERAL; |
| } |
| } |