| /* |
| * 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.util; |
| |
| import java.io.Serializable; |
| |
| /** |
| * A "typed string" utility class that improves the readability of generic code |
| * by using proper types. Equality and comparison are implemented by using both |
| * the concrete type and string value. |
| */ |
| public abstract class StringKey implements Comparable<StringKey>, Serializable { |
| |
| /** |
| * The hashcode is computed and stored since this type is expected to be used |
| * as a map key. |
| */ |
| private final int hashCode; |
| private final String value; |
| |
| /** |
| * Constructor. A <code>null</code> value is legal. |
| * |
| * @param value the value this key object represents |
| */ |
| protected StringKey(String value) { |
| this.value = value; |
| this.hashCode = getClass().getName().hashCode() * 13 |
| + (value == null ? 0 : value.hashCode()); |
| } |
| |
| /** |
| * Compares based on concrete type name and then value. |
| */ |
| public final int compareTo(StringKey o) { |
| if (getClass() == o.getClass()) { |
| if (value == null) { |
| return o.value == null ? 0 : -1; |
| } else if (o.value == null) { |
| return value == null ? 0 : 1; |
| } else { |
| return value.compareTo(o.value); |
| } |
| } |
| return getClass().getName().compareTo(o.getClass().getName()); |
| } |
| |
| /** |
| * Delegates to {@link #compareTo}. |
| */ |
| @Override |
| public final boolean equals(Object o) { |
| if (o == null) { |
| return false; |
| } |
| return compareTo((StringKey) o) == 0 ? true : false; |
| } |
| |
| /** |
| * Returns the value of the StringKey. |
| */ |
| public final String get() { |
| return value; |
| } |
| |
| @Override |
| public final int hashCode() { |
| return hashCode; |
| } |
| |
| /** |
| * Delegates to {@link #get()}. |
| */ |
| @Override |
| public String toString() { |
| return value; |
| } |
| } |