[camel] branch master updated: First cut of a migration guide

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davsclaus pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/camel.git


The following commit(s) were added to refs/heads/master by this push:
     new 2153b13  First cut of a migration guide
2153b13 is described below

commit 2153b1327eeb4ed86f42c7a60ea29fd3f6444f17
Author: Claus Ibsen <cl...@gmail.com>
AuthorDate: Tue Jan 29 09:11:37 2019 +0100

    First cut of a migration guide
---
 MIGRATION.md | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)

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+Apache Camel 3 Migration Guide
+==============================
+
+This document is intended for helping you migrate your Apache Camel applications
+from version 2.x to 3.0.
+
+Before you start
+----------------
+
+// TODO when we drop Java8
+// TODO Apache Camel 3 requires Java 11. Java 8 are no longer supported.
+
+Modularization of camel-core
+----------------------------
+
+One of the biggest change is the modularization of camel-core.
+In Camel 2.x camel-core was one JAR file, which now has been splitup into many JARs as follows:
+
+TODO: as table of all the modules
+- camel-core
+- camel-api
+ 
+Maven users of Apache Camel can keep using the dependency *camel-core* which will have transitive dependency on all of its modules, and therefore no migration is needed.
+However users whom wants to trim the size of the classes on the classpath, can use fine grained Maven dependency on only the modules needed.
+
+TODO: we need camel-core-minimal dependecy for just basic Camel
+
+
+Migrating custom components
+---------------------------
+
+You should depend on `camel-support` and not `camel-core` directly.
+
+The classes from `org.apache.camel.impl` that was intended to support Camel developers building custom components has been moved out of `camel-core` into `camel-support` into the `org.apache.camel.support` package. For example classes such as `DefaultComponent`, `DefaultEndpoint` etc has been moved and migration is nessasary.
+
+// TODO: Should we create a camel2-support JAR with an adapter to bridge between 2.x and 3.0
+
+Deprecated APIs and Components
+------------------------------
+
+All deprecated APIs and components from Camel 2.x has been removed in Camel 3.
+
+Migration Camel applications
+----------------------------
+
+The following API changes may affect your existing Camel applications, which needs to be migrated.
+
+### Moved APIs
+
+TODO: Should this be a table?
+TODO: Add the other moved classes/packages etc
+
+The classes from `org.apache.camel.impl` that was intended to support Camel developers building custom components has been moved out of `camel-core` into `camel-support` into the `org.apache.camel.support` package. If you have built custom Camel components that may have used some of these APIs you would then need to migrate.
+
+All the classes in `org.apache.camel.util.component` has been moved from the camel-core JAR to the package `org.apache.camel.support.component` in the `camel-support` JAR.
+
+The class `FileIdempotentRepository` has been moved from `org.apache.camel.processor.idempotent.FileIdempotentRepository` in the camel-core JAR to `org.apache.camel.support.processor.idempotent.FileIdempotentRepository` and moved to the `camel-suppor` JAR.
+
+The class `MemoryIdempotentRepository` has been moved from `org.apache.camel.processor.idempotent.MemoryIdempotentRepository` in the camel-core JAR to `org.apache.camel.support.processor.idempotent.MemoryIdempotentRepository` and moved to the `camel-suppor` JAR.
+
+The class `XsltAggregationStrategy` has been moved from `org.apache.camel.builder.XsltAggregationStrategy` in the camel-core JAR to `org.apache.camel.component.xslt.XsltAggregationStrategy` and moved to the `camel-xslt` JAR.
+
+The method `xslt` has been removed from `org.apache.camel.builder.AggregationStrategies`. Instead use the `XsltAggregationStrategy` from `camel-xslt` JAR directly.
+
+The getter/setter for `bindingMode` on `RestEndpoint` has been changed to use type `org.apache.camel.spi.RestConfiguration.RestBindingMode` from `camel-api` JAR. Instead of using this type class you can also call the setter method with string type instead.
+