com.google.web.bindery.requestfactory.shared.impl.SimpleProxyId Maven / Gradle / Ivy
/*
* 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 the type of BaseProxy object the id describes
*/
public class SimpleProxyId
{
/**
* 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
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
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
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
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 true if the id was created as an ephemeral id.
*/
public boolean wasEphemeral() {
return clientId != NEVER_EPHEMERAL;
}
}