com.google.gwt.dev.SessionModule Maven / Gradle / Ivy
/*
* Copyright 2009 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.dev;
import java.util.HashMap;
import java.util.Map;
/**
* Class used in the module drop-down box so that we can have a unique
* object in the dropdown. It is important that identity is maintained, such
* that if sessionKey, modulePanel, and moduleDisplayName are the same the
* same SessionModule instance is returned so == means the same as equals.
*/
final class SessionModule {
/**
* Used to cache instances so we always return the same SessionModule
* instance for the same key values.
*/
private static final Map instanceCache
= new HashMap();
/**
* Return a SessionModule instance for a given sessionKey, modulePanel, and
* moduleDisplayName, re-using an existing instance if it exists.
*
* @param sessionKey
* @param modulePanel
* @param moduleDisplayName
* @return unique SessionModule instance matching sessionKey and
* moduleDisplayName
*/
public static SessionModule create(String sessionKey,
Disconnectable modulePanel, String moduleDisplayName) {
SessionModule sessionModule = new SessionModule(sessionKey, modulePanel,
moduleDisplayName);
if (instanceCache.containsKey(sessionModule)) {
return instanceCache.get(sessionModule);
}
instanceCache.put(sessionModule, sessionModule);
return sessionModule;
}
// @NotNull
private final Disconnectable modulePanel;
// @NotNull
private final String moduleDisplayName;
// @NotNull
private final String sessionKey;
private SessionModule(String sessionKey, Disconnectable modulePanel,
String moduleDisplayName) {
if (sessionKey == null) {
throw new IllegalArgumentException("sessionKey cannot be null");
}
if (modulePanel == null) {
throw new IllegalArgumentException("modulePanel cannot be null");
}
if (moduleDisplayName == null) {
throw new IllegalArgumentException("moduleDisplayName cannot be null");
}
this.sessionKey = sessionKey;
this.modulePanel = modulePanel;
this.moduleDisplayName = moduleDisplayName;
}
// Even though we guarantee identity, we still need equals implemented
// so we can do so.
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null || getClass() != obj.getClass()) {
return false;
}
SessionModule other = (SessionModule) obj;
return sessionKey.equals(other.sessionKey)
&& modulePanel.equals(other.modulePanel)
&& moduleDisplayName.equals(other.moduleDisplayName);
}
public String getModuleDisplayName() {
return moduleDisplayName;
}
public Disconnectable getModulePanel() {
return modulePanel;
}
/**
* @return a unique key representing the session and the module name
* within that session.
*/
public String getStringKey() {
return sessionKey + moduleDisplayName;
}
@Override
public int hashCode() {
return sessionKey.hashCode() + 31 * moduleDisplayName.hashCode();
}
/**
* @return a string suitable for human display only, which consists of the
* module's short name, possibly including a disambiguator for multiple
* instances of the module name within the same session.
*/
@Override
public String toString() {
return moduleDisplayName;
}
}