001 /** 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018 019 package org.apache.hadoop.lib.wsrs; 020 021 import org.apache.hadoop.lib.util.Check; 022 023 import java.text.MessageFormat; 024 025 public abstract class Param<T> { 026 protected T value; 027 028 public T parseParam(String name, String str) { 029 Check.notNull(name, "name"); 030 try { 031 return (str != null && str.trim().length() > 0) ? parse(str) : null; 032 } catch (Exception ex) { 033 throw new IllegalArgumentException( 034 MessageFormat.format("Parameter [{0}], invalid value [{1}], value must be [{2}]", 035 name, str, getDomain())); 036 } 037 } 038 039 public T value() { 040 return value; 041 } 042 043 protected void setValue(T value) { 044 this.value = value; 045 } 046 047 protected abstract String getDomain(); 048 049 protected abstract T parse(String str) throws Exception; 050 051 public String toString() { 052 return value.toString(); 053 } 054 }