| /////////////////////////////////////////////////////////////// |
| * 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. |
| /////////////////////////////////////////////////////////////// |
| |
| [[library-uowfile,UoWFile Library]] |
| = UoWFile = |
| |
| [devstatus] |
| -------------- |
| source=libraries/uowfile/dev-status.xml |
| -------------- |
| |
| The UoWFile Library provides an easy way to bind file operations to UnitOfWorks. |
| |
| In other words, using this library you can easily attach files to your |
| Composites, mostly EntityComposites, so that if the UoW gets discarded, changes |
| to files are discarded too. Concurrent modifications are properly handled. |
| |
| Note that it has a performance impact relative to the files size as it |
| duplicates the file to keep a backup for eventual rollback. However, the API |
| provides a way to get non-managed handles on the attached files to keep your |
| read-only operations fast. |
| |
| The location of files is left to the developer using a private mixin. |
| |
| |
| include::../../build/docs/buildinfo/artifact.txt[] |
| |
| == Logging == |
| |
| The SLF4J Logger used by this library is named "org.qi4j.library.uowfile". |
| |
| |
| == Add an attached file to an Entity == |
| |
| Let's say you have the following Entity: |
| |
| [snippet,java] |
| ---- |
| source=libraries/uowfile/src/test/java/org/qi4j/library/uowfile/HasUoWFileTest.java |
| tag=entity |
| ---- |
| |
| To add an attached file to it you first need to extends HasUoWFileLifecycle: |
| |
| [snippet,java] |
| ---- |
| source=libraries/uowfile/src/test/java/org/qi4j/library/uowfile/HasUoWFileTest.java |
| tag=uowfile |
| ---- |
| |
| This provides you with the following contract: |
| |
| [snippet,java] |
| ---- |
| source=libraries/uowfile/src/main/java/org/qi4j/library/uowfile/singular/HasUoWFile.java |
| tag=contract |
| ---- |
| |
| Next you need to write the UoWFileLocator mixin: |
| |
| [snippet,java] |
| ---- |
| source=libraries/uowfile/src/test/java/org/qi4j/library/uowfile/HasUoWFileTest.java |
| tag=locator |
| ---- |
| |
| Assemble all this as follow: |
| |
| [snippet,java] |
| ---- |
| source=libraries/uowfile/src/test/java/org/qi4j/library/uowfile/HasUoWFileTest.java |
| tag=assembly |
| ---- |
| |
| You can now use the following methods on your EntityComposite: |
| |
| [snippet,java] |
| ---- |
| source=libraries/uowfile/src/test/java/org/qi4j/library/uowfile/HasUoWFileTest.java |
| tag=api |
| ---- |
| |
| |
| == Going plural == |
| |
| Now if you want to attach several files to one entity, this library provides a |
| simple mechanism allowing you to use any enum as discriminator. |
| |
| Let's say you have the following Entity: |
| |
| [snippet,java] |
| ---- |
| source=libraries/uowfile/src/test/java/org/qi4j/library/uowfile/HasUoWFilesTest.java |
| tag=entity |
| ---- |
| |
| It's the very same as the one used to start the singular file support described |
| above. |
| |
| To add an attached file to it you first need to write an enum and extends |
| HasUoWFilesLifecycle: |
| |
| [snippet,java] |
| ---- |
| source=libraries/uowfile/src/test/java/org/qi4j/library/uowfile/HasUoWFilesTest.java |
| tag=uowfile |
| ---- |
| |
| This provides you with the following contract: |
| |
| [snippet,java] |
| ---- |
| source=libraries/uowfile/src/main/java/org/qi4j/library/uowfile/plural/HasUoWFiles.java |
| tag=contract |
| ---- |
| |
| Next you need to write the UoWFileLocator mixin: |
| |
| [snippet,java] |
| ---- |
| source=libraries/uowfile/src/test/java/org/qi4j/library/uowfile/HasUoWFilesTest.java |
| tag=locator |
| ---- |
| |
| Assemble all this as follow: |
| |
| [snippet,java] |
| ---- |
| source=libraries/uowfile/src/test/java/org/qi4j/library/uowfile/HasUoWFilesTest.java |
| tag=assembly |
| ---- |
| |
| You can now use the following methods on your EntityComposite: |
| |
| [snippet,java] |
| ---- |
| source=libraries/uowfile/src/test/java/org/qi4j/library/uowfile/HasUoWFilesTest.java |
| tag=api |
| ---- |
| |
| |