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
019package org.apache.hadoop.lib.wsrs;
020
021import org.apache.hadoop.lib.util.Check;
022
023import java.text.MessageFormat;
024
025public 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}