/** * 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.camel; import java.util.List; import java.util.Map; import org.apache.camel.spi.Synchronization; import org.apache.camel.spi.UnitOfWork; /** * An Exchange is the message container holding the information during the entire routing of * a {@link Message} received by a {@link Consumer}. * <p/> * During processing down the {@link Processor} chain, the {@link Exchange} provides access to the * current (not the original) request and response {@link Message} messages. The {@link Exchange} * also holds meta-data during its entire lifetime stored as properties accessible using the * various {@link #getProperty(String)} methods. The {@link #setProperty(String, Object)} is * used to store a property. For example you can use this to store security, SLA related * data or any other information deemed useful throughout processing. If an {@link Exchange} * failed during routing the {@link Exception} that caused the failure is stored and accessible * via the {@link #getException()} method. * <p/> * An Exchange is created when a {@link Consumer} receives a request. A new {@link Message} is * created, the request is set as the body of the {@link Message} and depending on the {@link Consumer} * other {@link Endpoint} and protocol related information is added as headers on the {@link Message}. * Then an Exchange is created and the newly created {@link Message} is set as the in on the Exchange. * Therefore an Exchange starts its life in a {@link Consumer}. The Exchange is then sent down the * {@link Route} for processing along a {@link Processor} chain. The {@link Processor} as the name * suggests is what processes the {@link Message} in the Exchange and Camel, in addition to * providing out-of-the-box a large number of useful processors, it also allows you to create your own. * The rule Camel uses is to take the out {@link Message} produced by the previous {@link Processor} * and set it as the in for the next {@link Processor}. If the previous {@link Processor} did not * produce an out, then the in of the previous {@link Processor} is sent as the next in. At the * end of the processing chain, depending on the {@link ExchangePattern Message Exchange Pattern} (or MEP) * the last out (or in of no out available) is sent by the {@link Consumer} back to the original caller. * <p/> * Camel, in addition to providing out-of-the-box a large number of useful processors, it also allows * you to implement and use your own. When the Exchange is passed to a {@link Processor}, it always * contains an in {@link Message} and no out {@link Message}. The {@link Processor} <b>may</b> produce * an out, depending on the nature of the {@link Processor}. The in {@link Message} can be accessed * using the {@link #getIn()} method. Since the out message is null when entering the {@link Processor}, * the {@link #getOut()} method is actually a convenient factory method that will lazily instantiate a * {@link org.apache.camel.impl.DefaultMessage} which you could populate. As an alternative you could * also instantiate your specialized {@link Message} and set it on the exchange using the * {@link #setOut(org.apache.camel.Message)} method. Please note that a {@link Message} contains not only * the body but also headers and attachments. If you are creating a new {@link Message} the headers and * attachments of the in {@link Message} are not automatically copied to the out by Camel and you'll have * to set the headers and attachments you need yourself. If your {@link Processor} is not producing a * different {@link Message} but only needs to slightly modify the in, you can simply update the in * {@link Message} returned by {@link #getIn()}. * <p/> * See this <a href="http://camel.apache.org/using-getin-or-getout-methods-on-exchange.html">FAQ entry</a> * for more details. * */ public interface Exchange { String AUTHENTICATION = "CamelAuthentication"; String AUTHENTICATION_FAILURE_POLICY_ID = "CamelAuthenticationFailurePolicyId"; String ACCEPT_CONTENT_TYPE = "CamelAcceptContentType"; String AGGREGATED_SIZE = "CamelAggregatedSize"; String AGGREGATED_TIMEOUT = "CamelAggregatedTimeout"; String AGGREGATED_COMPLETED_BY = "CamelAggregatedCompletedBy"; String AGGREGATED_CORRELATION_KEY = "CamelAggregatedCorrelationKey"; String AGGREGATED_COLLECTION_GUARD = "CamelAggregatedCollectionGuard"; String AGGREGATION_STRATEGY = "CamelAggregationStrategy"; String AGGREGATION_COMPLETE_CURRENT_GROUP = "CamelAggregationCompleteCurrentGroup"; String AGGREGATION_COMPLETE_ALL_GROUPS = "CamelAggregationCompleteAllGroups"; String AGGREGATION_COMPLETE_ALL_GROUPS_INCLUSIVE = "CamelAggregationCompleteAllGroupsInclusive"; String ASYNC_WAIT = "CamelAsyncWait"; String BATCH_INDEX = "CamelBatchIndex"; String BATCH_SIZE = "CamelBatchSize"; String BATCH_COMPLETE = "CamelBatchComplete"; String BEAN_METHOD_NAME = "CamelBeanMethodName"; String BEAN_MULTI_PARAMETER_ARRAY = "CamelBeanMultiParameterArray"; String BINDING = "CamelBinding"; // do not prefix with Camel and use lower-case starting letter as its a shared key // used across other Apache products such as AMQ, SMX etc. String BREADCRUMB_ID = "breadcrumbId"; String CHARSET_NAME = "CamelCharsetName"; String CIRCUIT_BREAKER_STATE = "CamelCircuitBreakerState"; String CREATED_TIMESTAMP = "CamelCreatedTimestamp"; String CONTENT_ENCODING = "Content-Encoding"; String CONTENT_LENGTH = "Content-Length"; String CONTENT_TYPE = "Content-Type"; String COOKIE_HANDLER = "CamelCookieHandler"; String CORRELATION_ID = "CamelCorrelationId"; String DATASET_INDEX = "CamelDataSetIndex"; String DEFAULT_CHARSET_PROPERTY = "org.apache.camel.default.charset"; String DESTINATION_OVERRIDE_URL = "CamelDestinationOverrideUrl"; String DISABLE_HTTP_STREAM_CACHE = "CamelDisableHttpStreamCache"; String DUPLICATE_MESSAGE = "CamelDuplicateMessage"; String DOCUMENT_BUILDER_FACTORY = "CamelDocumentBuilderFactory"; String EXCEPTION_CAUGHT = "CamelExceptionCaught"; String EXCEPTION_HANDLED = "CamelExceptionHandled"; String EVALUATE_EXPRESSION_RESULT = "CamelEvaluateExpressionResult"; String ERRORHANDLER_CIRCUIT_DETECTED = "CamelFErrorHandlerCircuitDetected"; String ERRORHANDLER_HANDLED = "CamelErrorHandlerHandled"; String EXTERNAL_REDELIVERED = "CamelExternalRedelivered"; String FAILURE_HANDLED = "CamelFailureHandled"; String FAILURE_ENDPOINT = "CamelFailureEndpoint"; String FAILURE_ROUTE_ID = "CamelFailureRouteId"; String FATAL_FALLBACK_ERROR_HANDLER = "CamelFatalFallbackErrorHandler"; String FILE_CONTENT_TYPE = "CamelFileContentType"; String FILE_LOCAL_WORK_PATH = "CamelFileLocalWorkPath"; String FILE_NAME = "CamelFileName"; String FILE_NAME_ONLY = "CamelFileNameOnly"; String FILE_NAME_PRODUCED = "CamelFileNameProduced"; String FILE_NAME_CONSUMED = "CamelFileNameConsumed"; String FILE_PATH = "CamelFilePath"; String FILE_PARENT = "CamelFileParent"; String FILE_LAST_MODIFIED = "CamelFileLastModified"; String FILE_LENGTH = "CamelFileLength"; String FILE_LOCK_FILE_ACQUIRED = "CamelFileLockFileAcquired"; String FILE_LOCK_FILE_NAME = "CamelFileLockFileName"; String FILE_LOCK_EXCLUSIVE_LOCK = "CamelFileLockExclusiveLock"; String FILE_LOCK_RANDOM_ACCESS_FILE = "CamelFileLockRandomAccessFile"; String FILTER_MATCHED = "CamelFilterMatched"; String FILTER_NON_XML_CHARS = "CamelFilterNonXmlChars"; String GROUPED_EXCHANGE = "CamelGroupedExchange"; String HTTP_BASE_URI = "CamelHttpBaseUri"; String HTTP_CHARACTER_ENCODING = "CamelHttpCharacterEncoding"; String HTTP_METHOD = "CamelHttpMethod"; String HTTP_PATH = "CamelHttpPath"; String HTTP_PROTOCOL_VERSION = "CamelHttpProtocolVersion"; String HTTP_QUERY = "CamelHttpQuery"; String HTTP_RAW_QUERY = "CamelHttpRawQuery"; String HTTP_RESPONSE_CODE = "CamelHttpResponseCode"; String HTTP_RESPONSE_TEXT = "CamelHttpResponseText"; String HTTP_URI = "CamelHttpUri"; String HTTP_URL = "CamelHttpUrl"; String HTTP_CHUNKED = "CamelHttpChunked"; String HTTP_SERVLET_REQUEST = "CamelHttpServletRequest"; String HTTP_SERVLET_RESPONSE = "CamelHttpServletResponse"; String INTERCEPTED_ENDPOINT = "CamelInterceptedEndpoint"; String INTERCEPT_SEND_TO_ENDPOINT_WHEN_MATCHED = "CamelInterceptSendToEndpointWhenMatched"; String LANGUAGE_SCRIPT = "CamelLanguageScript"; String LOG_DEBUG_BODY_MAX_CHARS = "CamelLogDebugBodyMaxChars"; String LOG_DEBUG_BODY_STREAMS = "CamelLogDebugStreams"; String LOG_EIP_NAME = "CamelLogEipName"; String LOOP_INDEX = "CamelLoopIndex"; String LOOP_SIZE = "CamelLoopSize"; String MAXIMUM_CACHE_POOL_SIZE = "CamelMaximumCachePoolSize"; String MAXIMUM_ENDPOINT_CACHE_SIZE = "CamelMaximumEndpointCacheSize"; String MAXIMUM_TRANSFORMER_CACHE_SIZE = "CamelMaximumTransformerCacheSize"; String MAXIMUM_VALIDATOR_CACHE_SIZE = "CamelMaximumValidatorCacheSize"; String MESSAGE_HISTORY = "CamelMessageHistory"; String MESSAGE_HISTORY_HEADER_FORMAT = "CamelMessageHistoryHeaderFormat"; String MESSAGE_HISTORY_OUTPUT_FORMAT = "CamelMessageHistoryOutputFormat"; String MULTICAST_INDEX = "CamelMulticastIndex"; String MULTICAST_COMPLETE = "CamelMulticastComplete"; String NOTIFY_EVENT = "CamelNotifyEvent"; String ON_COMPLETION = "CamelOnCompletion"; String OVERRULE_FILE_NAME = "CamelOverruleFileName"; String PARENT_UNIT_OF_WORK = "CamelParentUnitOfWork"; String STREAM_CACHE_UNIT_OF_WORK = "CamelStreamCacheUnitOfWork"; String RECIPIENT_LIST_ENDPOINT = "CamelRecipientListEndpoint"; String RECEIVED_TIMESTAMP = "CamelReceivedTimestamp"; String REDELIVERED = "CamelRedelivered"; String REDELIVERY_COUNTER = "CamelRedeliveryCounter"; String REDELIVERY_MAX_COUNTER = "CamelRedeliveryMaxCounter"; String REDELIVERY_EXHAUSTED = "CamelRedeliveryExhausted"; String REDELIVERY_DELAY = "CamelRedeliveryDelay"; String REST_HTTP_URI = "CamelRestHttpUri"; String REST_HTTP_QUERY = "CamelRestHttpQuery"; String ROLLBACK_ONLY = "CamelRollbackOnly"; String ROLLBACK_ONLY_LAST = "CamelRollbackOnlyLast"; String ROUTE_STOP = "CamelRouteStop"; String REUSE_SCRIPT_ENGINE = "CamelReuseScripteEngine"; String COMPILE_SCRIPT = "CamelCompileScript"; String SAXPARSER_FACTORY = "CamelSAXParserFactory"; String SCHEDULER_POLLED_MESSAGES = "CamelSchedulerPolledMessages"; String SOAP_ACTION = "CamelSoapAction"; String SKIP_GZIP_ENCODING = "CamelSkipGzipEncoding"; String SKIP_WWW_FORM_URLENCODED = "CamelSkipWwwFormUrlEncoding"; String SLIP_ENDPOINT = "CamelSlipEndpoint"; String SPLIT_INDEX = "CamelSplitIndex"; String SPLIT_COMPLETE = "CamelSplitComplete"; String SPLIT_SIZE = "CamelSplitSize"; String TIMER_COUNTER = "CamelTimerCounter"; String TIMER_FIRED_TIME = "CamelTimerFiredTime"; String TIMER_NAME = "CamelTimerName"; String TIMER_PERIOD = "CamelTimerPeriod"; String TIMER_TIME = "CamelTimerTime"; String TO_ENDPOINT = "CamelToEndpoint"; String TRACE_EVENT = "CamelTraceEvent"; String TRACE_EVENT_NODE_ID = "CamelTraceEventNodeId"; String TRACE_EVENT_TIMESTAMP = "CamelTraceEventTimestamp"; String TRACE_EVENT_EXCHANGE = "CamelTraceEventExchange"; String TRY_ROUTE_BLOCK = "TryRouteBlock"; String TRANSFER_ENCODING = "Transfer-Encoding"; String UNIT_OF_WORK_EXHAUSTED = "CamelUnitOfWorkExhausted"; /** * @deprecated UNIT_OF_WORK_PROCESS_SYNC is not in use and will be removed in future Camel release */ @Deprecated String UNIT_OF_WORK_PROCESS_SYNC = "CamelUnitOfWorkProcessSync"; String XSLT_FILE_NAME = "CamelXsltFileName"; String XSLT_ERROR = "CamelXsltError"; String XSLT_FATAL_ERROR = "CamelXsltFatalError"; String XSLT_WARNING = "CamelXsltWarning"; /** * Returns the {@link ExchangePattern} (MEP) of this exchange. * * @return the message exchange pattern of this exchange */ ExchangePattern getPattern(); /** * Allows the {@link ExchangePattern} (MEP) of this exchange to be customized. * * This typically won't be required as an exchange can be created with a specific MEP * by calling {@link Endpoint#createExchange(ExchangePattern)} but it is here just in case * it is needed. * * @param pattern the pattern */ void setPattern(ExchangePattern pattern); /** * Returns a property associated with this exchange by name * * @param name the name of the property * @return the value of the given property or <tt>null</tt> if there is no property for * the given name */ Object getProperty(String name); /** * Returns a property associated with this exchange by name * * @param name the name of the property * @param defaultValue the default value to return if property was absent * @return the value of the given property or <tt>defaultValue</tt> if there is no * property for the given name */ Object getProperty(String name, Object defaultValue); /** * Returns a property associated with this exchange by name and specifying * the type required * * @param name the name of the property * @param type the type of the property * @return the value of the given property or <tt>null</tt> if there is no property for * the given name or <tt>null</tt> if it cannot be converted to the given type */ <T> T getProperty(String name, Class<T> type); /** * Returns a property associated with this exchange by name and specifying * the type required * * @param name the name of the property * @param defaultValue the default value to return if property was absent * @param type the type of the property * @return the value of the given property or <tt>defaultValue</tt> if there is no property for * the given name or <tt>null</tt> if it cannot be converted to the given type */ <T> T getProperty(String name, Object defaultValue, Class<T> type); /** * Sets a property on the exchange * * @param name of the property * @param value to associate with the name */ void setProperty(String name, Object value); /** * Removes the given property on the exchange * * @param name of the property * @return the old value of the property */ Object removeProperty(String name); /** * Remove all of the properties associated with the exchange matching a specific pattern * * @param pattern pattern of names * @return boolean whether any properties matched */ boolean removeProperties(String pattern); /** * Removes the properties from this exchange that match the given <tt>pattern</tt>, * except for the ones matching one ore more <tt>excludePatterns</tt> * * @param pattern pattern of names that should be removed * @param excludePatterns one or more pattern of properties names that should be excluded (= preserved) * @return boolean whether any properties matched */ boolean removeProperties(String pattern, String... excludePatterns); /** * Returns all of the properties associated with the exchange * * @return all the headers in a Map */ Map<String, Object> getProperties(); /** * Returns whether any properties has been set * * @return <tt>true</tt> if any properties has been set */ boolean hasProperties(); /** * Returns the inbound request message * * @return the message */ Message getIn(); /** * Returns the inbound request message as the given type * * @param type the given type * @return the message as the given type or <tt>null</tt> if not possible to covert to given type */ <T> T getIn(Class<T> type); /** * Sets the inbound message instance * * @param in the inbound message */ void setIn(Message in); /** * Returns the outbound message, lazily creating one if one has not already * been associated with this exchange. * <p/> * <br/><b>Important:</b> If you want to change the current message, then use {@link #getIn()} instead as it will * ensure headers etc. is kept and propagated when routing continues. Bottom line end users should rarely use * this method. * <p/> * <br/>If you want to test whether an OUT message have been set or not, use the {@link #hasOut()} method. * <p/> * See also the class java doc for this {@link Exchange} for more details and this * <a href="http://camel.apache.org/using-getin-or-getout-methods-on-exchange.html">FAQ entry</a>. * * @return the response * @see #getIn() */ Message getOut(); /** * Returns the outbound request message as the given type * <p/> * <br/><b>Important:</b> If you want to change the current message, then use {@link #getIn()} instead as it will * ensure headers etc. is kept and propagated when routing continues. Bottom line end users should rarely use * this method. * <p/> * <br/>If you want to test whether an OUT message have been set or not, use the {@link #hasOut()} method. * <p/> * See also the class java doc for this {@link Exchange} for more details and this * <a href="http://camel.apache.org/using-getin-or-getout-methods-on-exchange.html">FAQ entry</a>. * * @param type the given type * @return the message as the given type or <tt>null</tt> if not possible to covert to given type * @see #getIn(Class) */ <T> T getOut(Class<T> type); /** * Returns whether an OUT message has been set or not. * * @return <tt>true</tt> if an OUT message exists, <tt>false</tt> otherwise. */ boolean hasOut(); /** * Sets the outbound message * * @param out the outbound message */ void setOut(Message out); /** * Returns the exception associated with this exchange * * @return the exception (or null if no faults) */ Exception getException(); /** * Returns the exception associated with this exchange. * <p/> * Is used to get the caused exception that typically have been wrapped in some sort * of Camel wrapper exception * <p/> * The strategy is to look in the exception hierarchy to find the first given cause that matches the type. * Will start from the bottom (the real cause) and walk upwards. * * @param type the exception type * @return the exception (or <tt>null</tt> if no caused exception matched) */ <T> T getException(Class<T> type); /** * Sets the exception associated with this exchange * <p/> * Camel will wrap {@link Throwable} into {@link Exception} type to * accommodate for the {@link #getException()} method returning a plain {@link Exception} type. * * @param t the caused exception */ void setException(Throwable t); /** * Returns true if this exchange failed due to either an exception or fault * * @return true if this exchange failed due to either an exception or fault * @see Exchange#getException() * @see Message#setFault(boolean) * @see Message#isFault() */ boolean isFailed(); /** * Returns true if this exchange is transacted */ boolean isTransacted(); /** * Returns true if this exchange is an external initiated redelivered message (such as a JMS broker). * <p/> * <b>Important: </b> It is not always possible to determine if the message is a redelivery * or not, and therefore <tt>null</tt> is returned. Such an example would be a JDBC message. * However JMS brokers provides details if a message is redelivered. * * @return <tt>true</tt> if redelivered, <tt>false</tt> if not, <tt>null</tt> if not able to determine */ Boolean isExternalRedelivered(); /** * Returns true if this exchange is marked for rollback */ boolean isRollbackOnly(); /** * Returns the container so that a processor can resolve endpoints from URIs * * @return the container which owns this exchange */ CamelContext getContext(); /** * Creates a copy of the current message exchange so that it can be * forwarded to another destination * <p/> * Notice this operation invokes <tt>copy(false)</tt> */ Exchange copy(); /** * Creates a copy of the current message exchange so that it can be * forwarded to another destination * * @param safeCopy whether to copy exchange properties and message headers safely to a new map instance, * or allow sharing the same map instances in the returned copy. */ Exchange copy(boolean safeCopy); /** * Returns the endpoint which originated this message exchange if a consumer on an endpoint * created the message exchange, otherwise this property will be <tt>null</tt> */ Endpoint getFromEndpoint(); /** * Sets the endpoint which originated this message exchange. This method * should typically only be called by {@link org.apache.camel.Endpoint} implementations * * @param fromEndpoint the endpoint which is originating this message exchange */ void setFromEndpoint(Endpoint fromEndpoint); /** * Returns the route id which originated this message exchange if a route consumer on an endpoint * created the message exchange, otherwise this property will be <tt>null</tt> */ String getFromRouteId(); /** * Sets the route id which originated this message exchange. This method * should typically only be called by the internal framework. * * @param fromRouteId the from route id */ void setFromRouteId(String fromRouteId); /** * Returns the unit of work that this exchange belongs to; which may map to * zero, one or more physical transactions */ UnitOfWork getUnitOfWork(); /** * Sets the unit of work that this exchange belongs to; which may map to * zero, one or more physical transactions */ void setUnitOfWork(UnitOfWork unitOfWork); /** * Returns the exchange id (unique) */ String getExchangeId(); /** * Set the exchange id */ void setExchangeId(String id); /** * Adds a {@link org.apache.camel.spi.Synchronization} to be invoked as callback when * this exchange is completed. * * @param onCompletion the callback to invoke on completion of this exchange */ void addOnCompletion(Synchronization onCompletion); /** * Checks if the passed {@link org.apache.camel.spi.Synchronization} instance is * already contained on this exchange. * * @param onCompletion the callback instance that is being checked for * @return <tt>true</tt>, if callback instance is already contained on this exchange, else <tt>false</tt> */ boolean containsOnCompletion(Synchronization onCompletion); /** * Handover all the on completions from this exchange to the target exchange. * * @param target the target exchange */ void handoverCompletions(Exchange target); /** * Handover all the on completions from this exchange * * @return the on completions */ List<Synchronization> handoverCompletions(); }