Hi, What does the "merlin.deployment" property exactly specify.I read abt it yesterday somewhere on avalon site but can't find it now.
thanks --- Stephen McConnell <[EMAIL PROTECTED]> wrote: > Mathews Julien wrote: > > > Yeah Stephen, This helps in making things more > clear. > > > > Stephen wrote: > > The > > > >> avalon-repository > >> system uses artifact references as the key to > locating meta data > >> about embedded classloaders. The classloader > meta data is > >> maintained as a properties file with the .meta > extension. For > >> example the above artifact meta address > translates to: > >> The content of the meta file is automatically > generated using the > >> avalon-plugin avalon:artifact goal. > > > > > > > > How does the avalon:artifact goal generate the > meta information in the > > .meta info. I mean where does is get the info abt > the "implementation > > dependencies" etc. > > > >> From some project.xml or some meta tags or where > ? > > The avalon:artifact goal scans the project PMC > (Maven's project > definition) and looks at all of the dependencies > that are listed. For > each dependency, the plugin looks for a declared > dependency properties > and does some special processing for properties > named > "avalon.classloader". For example the following is > a dependency > declaration within the merlin/kernel/impl > project.xml: > > <dependency> > <groupId>merlin</groupId> > <artifactId>merlin-api</artifactId> > <version>3.3-SNAPSHOT</version> > <properties> > > <avalon.classloader>spi</avalon.classloader> > </properties> > </dependency> > > The plugin will look for the property name > "avalon.classloader" and if > the property value is "api" then the dependency will > be loaded into an > api classloader. If the property is "spi" the > dependency will be loaded > into a spi classloader which is created as a child > of the spi loader. > If no "avalon.classloader" property is declared that > dependency will be > loaded into a impl classloader which is created as a > child of the spi > loader. > > The avalon-repository bootstrapping system will > attempt to construct a > classloader chain that looks like the following: > > |----------------------| > | api classloader | > |----------------------| > ^ > | > |----------------------| > | spi classloader | > |----------------------| > ^ > | > |----------------------| > | imp classloader | > |----------------------| > > > > Could you pls explain a little bit. > > The avalon:artifact source file is a jelly script in > > avalon/util/plugin/plugin.jelly. > > Cheers, Stephen. > > > > Thanks > > Mathews > > > > > > > >> From: Stephen McConnell <[EMAIL PROTECTED]> > >> Reply-To: "Avalon framework users" > <[EMAIL PROTECTED]> > >> To: Avalon Users <[EMAIL PROTECTED]> > >> Subject: [merlin] introduction to embedding > >> Date: Sun, 25 Jan 2004 16:17:19 +0100 > >> > >> > >> This is a little introduction to embedding > Merlin. The descriptions > >> starts off with an overview of the Avalon > Repository bootstrapping > >> system - which at the end of the day is the core > embedding technology > >> used within the merlin platform. > >> > >> Simple Embedding Example: > >> ------------------------- > >> > >> 1. creating an initial context > >> > >> File cache = new File( "my-cache" ); > >> InitialContext context = new > DefaultInitialContext( cache ); > >> > >> The above code defines a cache directory for > the repository > >> system to use when loading resources needed in > your embedded > >> application - and provides the directory as an > argument when > >> creating a new InitialContext object. The > InitialContext is > >> you hook into the repository system and the > embedding machinery. > >> > >> 2. declare what you want to embed > >> > >> String spec = > >> > "artifact:avalon-logging/avalon-logkit?version=1.0-SNAPSHOT" > >> Artifact artifact = > >> Artifact.createArtifact( spec ); > >> > >> An artifact is a logical reference to a jar > file (or other type > >> of resource) that the repository can access. > The avalon-repository > >> system uses artifact references as the key to > locating meta data > >> about embedded classloaders. The classloader > meta data is > >> maintained as a properties file with the .meta > extension. For > >> example the above artifact meta address > translates to: > >> > >> > [host]/avalon-logging/jars/avalon-logkit-impl-1.0-SNAPSHOT.jar.meta > >> > >> The content of the meta file is automatically > generated using the > >> avalon-plugin avalon:artifact goal. Two real > examples are attached > >> (the logkit factory and the merlin factory > meta). > >> > >> The contents of the meta file includes: > >> > >> * a ordered list of jar files that are > required to > >> construct a classloader for the embedded > application > >> > >> * the name of a factory class to be used as > the embedded > >> instance creator > >> > >> 3. create the factory > >> > >> Using the initial context and the artifact you > now have everything > >> you need to create you embedded instance. > >> > >> Builder builder = m_context.newBuilder( > artifact ); > >> Factory factory = builder.getFactory(); > >> > >> Behind the scenes the avalon-repository system > has gone off, pulled > >> down the meta data, downloaded and cached all > of the classloader > >> entries, constructed a new classloader, and > instantiated the > >> factory. > >> > >> 4. parameterizing the factory > >> > >> The factory object is the central entry point > of === message truncated === __________________________________ Do you Yahoo!? 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