001// ***************************************************************************************************************************
002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
003// * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
004// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
005// * with the License.  You may obtain a copy of the License at                                                              *
006// *                                                                                                                         *
007// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
008// *                                                                                                                         *
009// * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an  *
010// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the        *
011// * specific language governing permissions and limitations under the License.                                              *
012// ***************************************************************************************************************************
013package org.apache.juneau.internal;
014
015import static org.apache.juneau.common.internal.StringUtils.*;
016import static org.apache.juneau.common.internal.ThrowableUtils.*;
017
018/**
019 * Builder class for {@link Exception} objects.
020 *
021 * <h5 class='section'>See Also:</h5><ul>
022 * </ul>
023 *
024 * @param <T> The exception class.
025 */
026@FluentSetters
027public class ExceptionBuilder<T extends Throwable> {
028
029   private final Class<T> type;
030   private String message;
031   private Throwable causedBy;
032
033   /**
034    * Default constructor.
035    * @param type The exception type to create.
036    */
037   public ExceptionBuilder(Class<T> type) {
038      this.type = type;
039   }
040
041   /**
042    * Specifies the exception message.
043    *
044    * @param msg The exception message.  Can be <jk>null</jk>.
045    *    <br>If <jk>null</jk>, then the caused-by message is used if available.
046    * @param args The exception message arguments.
047    * @return This object.
048    */
049   @FluentSetter
050   public ExceptionBuilder<T> message(String msg, Object...args) {
051      message = format(msg, args);
052      return this;
053   }
054
055   /**
056    * Specifies the caused-by exception.
057    *
058    * @param value The caused-by exception.  Can be <jk>null</jk>.
059    * @return This object.
060    */
061   @FluentSetter
062   public ExceptionBuilder<T> causedBy(Throwable value) {
063      causedBy = value;
064      return this;
065   }
066
067   // <FluentSetters>
068
069   // </FluentSetters>
070
071   /**
072    * Creates the exception.
073    *
074    * @return The exception.
075    */
076   public T build() {
077      try {
078         return type.getConstructor(String.class, Throwable.class).newInstance(message, causedBy);
079      } catch (Exception e) {
080         throw asRuntimeException(e);
081      }
082   }
083}