001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.camel;
018
019/**
020 * An exception caused when a mandatory header is not available on a message
021 * {@link Exchange}
022 *
023 * @see org.apache.camel.support.ExchangeHelper#getMandatoryHeader(Exchange, String, Class)
024 */
025public class NoSuchHeaderException extends CamelExchangeException {
026
027    private final String headerName;
028    private final transient Class<?> type;
029
030    public NoSuchHeaderException(Exchange exchange, String headerName, Class<?> type) {
031        super("No '" + headerName + "' header available of type: " + type.getName()
032              + reason(exchange, headerName), exchange);
033        this.headerName = headerName;
034        this.type = type;
035    }
036
037    public String getHeaderName() {
038        return headerName;
039    }
040
041    public Class<?> getType() {
042        return type;
043    }
044
045    protected static String reason(Exchange exchange, String propertyName) {
046        Object value = exchange.getProperty(propertyName);
047        return valueDescription(value);
048    }
049
050    static String valueDescription(Object value) {
051        if (value == null) {
052            return "";
053        }
054        return " but has value: " + value + " of type: " + value.getClass().getCanonicalName();
055    }
056}