Java tutorial
/**************************************************************** * Licensed to the Apache Software Foundation (ASF) under one * * or more contributor license agreements. See the NOTICE file * * distributed with this work for additional information * * regarding copyright ownership. The ASF licenses this file * * to you 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 org.apache.mailet; import java.util.Objects; import com.google.common.base.MoreObjects; import com.google.common.base.Preconditions; import com.google.common.base.Strings; /** * Strong typing for attribute name, which represents the name of an attribute stored in a mail. * * @since Mailet API v3.2 */ public class AttributeName { private final String name; public static AttributeName of(String name) { Preconditions.checkNotNull(name, "`name` is compulsory"); Preconditions.checkArgument(!Strings.isNullOrEmpty(name), "`name` should not be empty"); return new AttributeName(name); } private AttributeName(String name) { this.name = name; } public String asString() { return name; } @Override public final boolean equals(Object o) { if (o instanceof AttributeName) { AttributeName that = (AttributeName) o; return Objects.equals(this.name, that.name); } return false; } @Override public final int hashCode() { return Objects.hash(name); } @Override public String toString() { return MoreObjects.toStringHelper(this).add("name", name).toString(); } }