git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@274764 13f79535-47bb-0310-9956-ffa450edef68master
| @@ -1,68 +0,0 @@ | |||
| <?xml version="1.0"?> | |||
| <document> | |||
| <properties> | |||
| <index value="2"/> | |||
| <author email="antoine@apache.org">Antoine Levy-Lambert</author> | |||
| <title>Antlib Class Loaders</title> | |||
| </properties> | |||
| <body> | |||
| <section name="Jose Alberto Fernandez"> | |||
| <p> | |||
| Let me first say that this feature appeared by the need to be able to say, | |||
| </p> | |||
| <source><![CDATA[ | |||
| <antlib name="A" classpathref="XYZ"/> | |||
| <antlib name="B" classpathref="XYZ"/> | |||
| ]]></source> | |||
| <p> | |||
| And being able to make sure that B and A use the same classLoader | |||
| and therefore they can use each other components. | |||
| </p> | |||
| <p> | |||
| My solution at the time was this idea of a named classloader that | |||
| you could define using a classpath, and then tell your antlibs use | |||
| this or that classloader, if you use the same classloader visibility | |||
| is guaranteed. | |||
| </p> | |||
| </section> | |||
| <section name="Stefan Bodewig 23.04.2003 17:11"> | |||
| ... | |||
| <p> | |||
| I understand that usecase (using the same class loader for 2 different antlibs) | |||
| and think it's important. See Steve | |||
| Loughran's comment on the .NET tasks wanting to have access to the | |||
| datatypes defined in the cpptasks project for example. | |||
| </p><p> | |||
| Take a look at what Costin had done to <taskdef> and <typedef> with | |||
| the loaderref attribute. This has now (i.e. CVS HEAD) been | |||
| generalized in ClasspathUtils, the infrastructure for named | |||
| classloaders is there - at least the foundation for it. | |||
| </p><p> | |||
| Stefan | |||
| </p> | |||
| </section> | |||
| <section name="Costin Manolache 29.04.2003 18:52"> | |||
| <p> | |||
| The main issue is how to enforce ordering to deal with dependencies | |||
| between the antlibs. | |||
| </p><p> | |||
| Or simply do not deal with dependencies, ie antlibs must not (yet) | |||
| depend on on the other, except for the core ones. | |||
| </p><p> | |||
| Using an unified class loader ( at least as default ) - like jboss is doing, | |||
| or like JMX loading policy - has a lot of benefits. It also has some cases | |||
| that are not well covered - so we'll probably need to deal with both | |||
| "unified loader" and "loader hierarchy" cases. | |||
| </p> | |||
| </section> | |||
| </body> | |||
| </document> | |||
| @@ -1,45 +0,0 @@ | |||
| <?xml version="1.0"?> | |||
| <document> | |||
| <properties> | |||
| <index value="2"/> | |||
| <author email="antoine@apache.org">Antoine Levy-Lambert</author> | |||
| <title>Antlib Contract</title> | |||
| </properties> | |||
| <body> | |||
| <section name="definition of antlibs"> | |||
| <p> | |||
| Antlibs are special-purpose jar files containing a deployment descriptor called antlib.xml. | |||
| These jar files contain ant tasks and types. In the near future, they will also contain custom components too able to act as filters, mappers, ... | |||
| </p> | |||
| <p> | |||
| The precise location of the deployment descriptor is already a point of discussion. (such as com/xyz/anttasks/antlib.xml). <a href="antlib_descriptors.html#concerns concerning the location of the descriptor (Costin Manolache)">Costin Manolache would prefer deployment descriptors to live in packages </a> The original proposal is to put the deployment descriptor into META-INF/antlib.xml in the jar files. | |||
| </p> | |||
| </section> | |||
| <section name="loading of antlibs"> | |||
| <p> | |||
| Under ant.home, a new subdirectory autolib would be created for antlibs to be loaded "spontaneously". | |||
| </p> | |||
| <p> | |||
| antlibs can also be loaded explicitly with an <antlib/> task. | |||
| </p> | |||
| </section> | |||
| <section name="links"> | |||
| <p> | |||
| <a href="http://cvs.apache.org/viewcvs.cgi/*checkout*/ant/proposal/sandbox/antlib/docs/manual/CoreTasks/antlib.html?rev=HEAD">Antlib task documentation</a> | |||
| </p> | |||
| <p> | |||
| <a href="http://cvs.apache.org/viewcvs.cgi/*checkout*/ant/proposal/sandbox/antlib/docs/manual/CoreTasks/antjar.html?rev=HEAD">Antjar task documentation</a> | |||
| </p> | |||
| </section> | |||
| <section name="todo"> | |||
| <subsection name="versions"> | |||
| <p> | |||
| ant-required-version, antlib-version (version used to build the library) | |||
| </p> | |||
| </subsection> | |||
| </section> | |||
| </body> | |||
| </document> | |||
| @@ -1,71 +0,0 @@ | |||
| <?xml version="1.0"?> | |||
| <document> | |||
| <properties> | |||
| <index value="2"/> | |||
| <author email="antoine@apache.org">Antoine Levy-Lambert</author> | |||
| <title>Antlib Descriptor</title> | |||
| </properties> | |||
| <body> | |||
| <section name="antlib descriptor in the proposal"> | |||
| <source><![CDATA[ | |||
| <antlib version="1.5" > | |||
| <task name="mkdir" class="org.apache.tools.ant.taskdefs.Mkdir"/> | |||
| ... | |||
| <data-type name="fileset" class="org.apache.tools.ant.types.FileSet"/> | |||
| ... | |||
| <role name="filter" class="org.apache.tools.ant.filters.ChainableReader"/> | |||
| ... | |||
| <filter name="escapeunicode" class="org.apache.tools.ant.filters.EscapeUnicode"/> | |||
| </antlib> | |||
| ]]></source> | |||
| <p> | |||
| This is the layout of the antlib descriptor in the proposal. In each antlib jar file, the descriptor would be found under | |||
| META-INF/antlib.xml | |||
| </p> | |||
| </section> | |||
| <section name="concerns concerning the location of the descriptor (Costin Manolache)"> | |||
| My concerns with getResources() as opposed to | |||
| getResource( PACKAGE/antlib.xml): | |||
| <ol> | |||
| <li> | |||
| startup time. In order to load one library you need to process all | |||
| of them. It can be resolved with caching the result and looking at .jar | |||
| modifications. Most likely we'll have dozens of antlibs - and that'll only | |||
| grow in time. The processing of (all) TLDs at startup ( for tomcat ) adds a | |||
| very visible overhead on startup, and at least tomcat is a long-running | |||
| process. | |||
| </li> | |||
| <br/> | |||
| <li> | |||
| Placing multiple antlibs in a single jar may be trickier. | |||
| </li> | |||
| <br/> | |||
| <li> | |||
| It may place too much emphasis on the .jars and filesystem layout. | |||
| </li> | |||
| <br/> | |||
| <li> | |||
| A bit harder to control ( as we know from c-logging and JAXP ), | |||
| </li> | |||
| <br/> | |||
| <li>Explicit control over what antlibs are to be used - versus loading | |||
| everything. Well - I like "magic" loading, but a lot of things in ant | |||
| are done explicitely. | |||
| </li> | |||
| </ol> | |||
| <br/> | |||
| <p> | |||
| I have no problem accepting a getResources() solution ( just like I'm | |||
| ok with using XML - but not any XML :-), but those issues should be | |||
| considered. | |||
| <br/> | |||
| A lot of the "mess" in ant is the result of doing some things without | |||
| considering all implications or just as side effect of how code happened | |||
| to work. That's why I'm so strongly for breaking things down to individual | |||
| problems instead of a bundle solution. | |||
| </p> | |||
| Costin | |||
| </section> | |||
| </body> | |||
| </document> | |||
| @@ -1,151 +0,0 @@ | |||
| <?xml version="1.0" encoding="UTF-8"?> | |||
| <document> | |||
| <properties> | |||
| <index value="2"/> | |||
| <author email="antoine@apache.org">Antoine Levy-Lambert</author> | |||
| <title>Antlib Namespaces</title> | |||
| </properties> | |||
| <body> | |||
| <section name="J.Pietschmann 03.05.2003 17:25"> | |||
| <p> | |||
| Nicola Ken Barozzi wrote: | |||
| < This seems interesting, and brings up what XML namespaces can be used for. | |||
| </p><p> | |||
| XML namespaces are indented to disambiguate short local element | |||
| and attribute names. Any sematic associated to XML namespaces | |||
| beside this has to be weighted carefully. | |||
| </p><p> | |||
| Lets take an example. There are two projects, Foo and Bar, | |||
| each providing a task, lets call them <foo> and <bar> | |||
| respectively. Both tasks take a <part> child, by coincidence. | |||
| Of course, because the projects act uncoordinated, the <part> | |||
| child element has a different semantic. In order to make this | |||
| clearer, let's say the Foo <part> takes an optional <mumble> | |||
| child while the Bar <part> takes three mandatory <xonx> | |||
| children. | |||
| </p><p> | |||
| Someone finds both the <foo> and the <bar> task exciting and | |||
| wants to use both in an Ant build file. No problem so far: | |||
| because ot the way Ant elements get their child elements and | |||
| create associated Java objects, this should work. | |||
| Now said someone got a super-duper schema directed XML editor | |||
| and wants to use it for editing the build.xml file. He asks | |||
| all projects for a schema (DTD, XSD, RNG, whatever) for this | |||
| purpose and merges them in order to get a schema for his build | |||
| file. At this point the two <part> elements are likely to clash | |||
| (at least for DTDs, where element names are global). While | |||
| it is possible to merge the content models so that <part> now | |||
| takes either an optional <mumble> or three <xonx> children, this | |||
| would allow the user to put <xonx> children into the <part> of | |||
| the <foo> task. This is only a minor inconvenience for most | |||
| people, but an unthinkable horror for true purists. | |||
| </p><p> | |||
| Introduce namespaces: the Foo projects names its namespace | |||
| "http://www.fooproject.org/anttask" while the Bar project uses | |||
| "URI:bar" or whatever. For the XML parser it is only really | |||
| important that two different strings are used. You see, the | |||
| longer the strings the less tha chance they will clash, and | |||
| they probably won't clash if they start with the URLs of the | |||
| project's homepages (the intent behind the recommendation to | |||
| use URLs, because it's the closest thing to a global registry | |||
| you can get short of actually creating a global registry). | |||
| Anyway, because the expanded names of the <part> elements are | |||
| now "{http://www.fooproject.org/anttask}part" and "{URI:bar}part" | |||
| respectively they obviously no longer clash. | |||
| BTW you can write this as | |||
| </p> | |||
| <source><![CDATA[ | |||
| <target name="foo"> | |||
| <foo xmlns="http://www.fooproject.org/anttask"> | |||
| <part> | |||
| <mumble> | |||
| </part> | |||
| </foo> | |||
| <bar xmlns="URI:bar"> | |||
| <part><xonx/><xonx/><xonx/></part> | |||
| </bar> | |||
| <target> | |||
| ]]></source> | |||
| <p> | |||
| or as | |||
| </p> | |||
| <source><![CDATA[ | |||
| <target name="foo" | |||
| xmlns:foo="http://www.fooproject.org/anttask" | |||
| xmlns:bar="URI:bar"> | |||
| <foo:foo> | |||
| <foo:part> | |||
| <foo:mumble> | |||
| </foo:part> | |||
| </foo:foo> | |||
| <bar:bar> | |||
| <bar:part><bar:xonx/><bar:xonx/><bar:xonx/></bar:part> | |||
| </bar:bar> | |||
| <target> | |||
| ]]></source> | |||
| <p> | |||
| take your pick (if you think the "foo" and "bar" prefixes are too | |||
| long, use "a" and "b" instead, it doesn't matter). | |||
| </p><p> | |||
| So far, the namespace names should only be different for different | |||
| projects, so why is it dangerous to associate some semantic with it, | |||
| like letting them point to a jar file? The problem is again that | |||
| general purpose XML tools, like the above mentioned super-duper XML | |||
| editor may associate their own semantics with the namespace, like | |||
| how to auto-format certain elements. This information will be stored | |||
| in some config files, and it requires that the namespace name is | |||
| the same until the semantics of the elements in it have changed | |||
| enough that it warrants assigning a new namespace name. | |||
| </p><p> | |||
| Summary: | |||
| </p> | |||
| <ol> | |||
| <li> | |||
| XML namespaces are there to facilitate aggregation of XML adhering | |||
| to schemas (content models) of different, uncoordinated origin. | |||
| </li><li> | |||
| XML Namespaces should be used in a way that no end user action | |||
| can result in two namespace names becoming unintentionally the | |||
| same. | |||
| </li><li> | |||
| XML Namespace names should preferably be assigned by the people | |||
| or project which specifies the semantics of the XML elemnets and | |||
| attributes therein. | |||
| </li><li> | |||
| XML Namespace names should be kept unchanged until a change of | |||
| the semantic of the elements warrants a change. | |||
| </li><li> | |||
| Good tools should not monopolize XML namespace syntax for its | |||
| own semantics. | |||
| </li> | |||
| </ol> | |||
| <p> | |||
| The schema directed editor should provide an example hoe tools | |||
| can take advantage of XML namespaces: use them as a key into a | |||
| DB/config to get it's own associated semantic. | |||
| In particular for Ant/Antlib I can imagine that each library | |||
| provides a factory object associated to the XML namespace for | |||
| the library. | |||
| </p><p> | |||
| The FOP parser uses such a two stage lookup: first the namespace | |||
| is used to get a factory object from a hash table, then the factory | |||
| is used with the local XML element name to create a Java object | |||
| which is inserted into the FO tree. The hash table with the factories | |||
| is initialized at startup, the associations between namespace name | |||
| and factory class name is read from a Services file. Want to add | |||
| a FOP extension? Get the default Services file, add a line with | |||
| your namespace-to-factoryclassname mapping put it into the jar with | |||
| all the classes and drop the jar as first into the classpath. If the | |||
| user wants to use multiple extensions, well, edit the main Services | |||
| instead, dead easy. | |||
| </p><p> | |||
| HTH | |||
| J.Pietschmann | |||
| </p> | |||
| </section> | |||
| </body> | |||
| </document> | |||
| @@ -1,48 +0,0 @@ | |||
| <?xml version="1.0"?> | |||
| <document> | |||
| <properties> | |||
| <index value="2"/> | |||
| <author email="antoine@apache.org">Antoine Levy-Lambert</author> | |||
| <title>Antlib Roadmap</title> | |||
| </properties> | |||
| <body> | |||
| <section name="Antlib with tasks and types only"> | |||
| <p> | |||
| Let me quote here Stefan Bodewig - April 24th 2003. | |||
| </p> | |||
| <p> | |||
| Let's make a version of antlib that knows about two predefined roles, | |||
| task and data-type. I think this is already feature complete in the | |||
| proposal (which does even more). | |||
| </p> | |||
| <p> | |||
| Let's move this code with the restriction to tasks and types into the | |||
| main branch ASAP. Let's sort out the classloading requirements as | |||
| well as the interplay of antlib with taskdef and typedef here. | |||
| </p> | |||
| <p> | |||
| After this flies, I'd expect us to get roles sorted out. If we feel | |||
| like removing the difference between tasks and types, we can do so | |||
| then as well. | |||
| </p> | |||
| </section> | |||
| <section name="Roles and components in build files"> | |||
| <p> | |||
| A second step : make a detailed proposal concerning roles and implement roles and components in ant core. | |||
| </p> | |||
| </section> | |||
| <section name="Roles and components in antlibs"> | |||
| <p> | |||
| Once roles and components are properly defined and implemented in ant core, we would revisit <antlib> and implement roles and components there. | |||
| </p> | |||
| </section> | |||
| <section name="Namespaces"> | |||
| <p> | |||
| After we have antlibs, roles, and components, we should specify how we are going to proceed concerning namespaces and prefixes. | |||
| </p> | |||
| </section> | |||
| </body> | |||
| </document> | |||
| @@ -1,68 +0,0 @@ | |||
| <?xml version="1.0"?> | |||
| <document> | |||
| <properties> | |||
| <index value="2"/> | |||
| <author email="jalberto@cellectivity.com">Jose Alberto Fernandez</author> | |||
| <author email="antoine@apache.org">Antoine Levy-Lambert</author> | |||
| <title>Antlib</title> | |||
| </properties> | |||
| <body> | |||
| <section name="Introduction"> | |||
| <p>The purpose of this document is to summarize the discussions taking | |||
| place concerning antlib. I will try to always give proper credit, and to represent | |||
| honestly different views expressed on the ant development mailing list. | |||
| Send comments/criticisms if you are not happy with these documents. | |||
| </p> | |||
| </section> | |||
| <section name="Overview"> | |||
| <p> | |||
| Jose Alberto Fernandez 03.04.2003 18:25 | |||
| </p> | |||
| <p> | |||
| There are the following features in the antlib proposal: | |||
| <ol> | |||
| <li> | |||
| antlib & antjar | |||
| </li> | |||
| <li> | |||
| type definitions that allow to define new implementations of mappers, selectors, paths, conditions, etc. That you can define in your antlib and a way to link this with the introspectors (I am not sure how complete this is). | |||
| </li> | |||
| <li> | |||
| A scoping framework for the symbol tables needed to manage the antlib definitions (I think ANT has something on this regard) | |||
| </li> | |||
| <li> | |||
| A framework for managing classloaders where you can specify which classloader to use when loading an antlib. | |||
| </li> | |||
| </ol> | |||
| </p> | |||
| </section> | |||
| <section name="Specific themes"> | |||
| <ol> | |||
| <li> | |||
| <a href="antlib_contract.html"> Antlib contract</a> | |||
| </li> | |||
| <li> | |||
| <a href="antlib_descriptors.html"> Antlib descriptors</a> | |||
| </li> | |||
| <li> | |||
| <a href="antlib_classloaders.html">Classloaders</a> | |||
| </li> | |||
| <li> | |||
| <a href="roles.html">Roles, polymorphism, introspection</a> | |||
| </li> | |||
| <li> | |||
| <a href="antlib_namespaces.html">XML namespaces</a> | |||
| </li> | |||
| <li> | |||
| <a href="antlib_roadmap.html">Roadmap</a> | |||
| </li> | |||
| </ol> | |||
| </section> | |||
| </body> | |||
| </document> | |||
| @@ -1,263 +0,0 @@ | |||
| <?xml version="1.0"?> | |||
| <document> | |||
| <properties> | |||
| <index value="2"/> | |||
| <author email="antoine@apache.org">Antoine Levy-Lambert</author> | |||
| <title>Roles</title> | |||
| </properties> | |||
| <body> | |||
| <section name="What is a role"> | |||
| <p> | |||
| I am quoting here Jose Alberto Fernandez 26.04.2003 22:05: | |||
| Roles allow defining families of objects (members of a role) that can be | |||
| used by tasks or inner elements developed separately. | |||
| The developer of the object accepting a particular role as a subelement | |||
| has no knowledge of the implementation of the object but much more | |||
| importantly it has no knowledge of the XML element tag used to refer | |||
| to this subelement in the XML file. | |||
| </p> | |||
| <p> | |||
| In the antlib proposal, there are two preset roles : | |||
| <ul> | |||
| <li>task</li> | |||
| <li>datatype</li> | |||
| </ul> | |||
| Examples of other roles are : | |||
| <ul> | |||
| <li>mapper</li> | |||
| <li>filter</li> | |||
| </ul> | |||
| </p> | |||
| <p> | |||
| What does it all mean? It means we can now write a task, well typed, which | |||
| can be accept different XML subelements depending on the declarations of | |||
| other objects present on the build. The vendor specific elements of | |||
| <ejbjar>, <jspc> and others are typical examples of where this capability | |||
| can be very useful. Other parts of core could benefit of course. | |||
| </p> | |||
| <br/> | |||
| <subsection name="What do they do that is no possible in ANT"> | |||
| <p> | |||
| They allow IntrospectionHelper to connect an XML subelement eventhough | |||
| introspection cannot find a create or add/Configured method for it. | |||
| It is a well typed methanism, the parent object will only be passed objects | |||
| that it knows how to deal with. And the parent object does not need to have | |||
| any knowledge of what currently available members are on the role. | |||
| </p> | |||
| </subsection> | |||
| </section> | |||
| <section name="roles versus DynamicConfigurator"> | |||
| <p> | |||
| The closest thing in ANT today is DynamicConfigurator but its purpose | |||
| is on the other way around. Given an elementTag with no matching method | |||
| it is up to the parent object to try to make sense of it. | |||
| If we were to use this mechanism to accomplish what roles try to do, | |||
| it would require the parent object implementor to be aware of where | |||
| to find the correct definition (remember it is a 3rd party implementation) | |||
| and perform the creation. It will be also its responsibility to | |||
| resolve type conflicts, name collisions, etc. This are all things | |||
| that should be done by IntrospectionHelper directly. | |||
| </p> | |||
| <p> | |||
| Also notice that Roles do not supersede DynamicConfigurator. On one hand roles | |||
| let external implementations to be considered as possible subelements | |||
| of a parent object, on the other hand, DynamicConfigurator allows a node | |||
| to decide given its current state what is the meaning of a particular element. | |||
| This cannot be done by roles in the general case, and that is good. | |||
| </p> </section> | |||
| <section name="Implementation of roles in the proposal"> | |||
| <p>this section quotes Jose Alberto Fernandez</p> | |||
| <p> | |||
| Here I may deviate from the exact code and add thoughts about where | |||
| do I think it should go. | |||
| </p> | |||
| <subsection name="Usage of Roles"> | |||
| <p> | |||
| The principle is very simple: | |||
| </p> | |||
| <br/> | |||
| <ol> | |||
| <li> | |||
| A role is defined by an interface. This interface is the parameter | |||
| for a new special family of addConfigured(<interface>) methods. | |||
| </li> | |||
| <li> | |||
| <p> | |||
| When IntrospectionHelper fails to find a create/add method for the | |||
| element, it will look at all the roles used in the addConfigured | |||
| methods and on each of those roles will try to find an object declared | |||
| with that element-tag name. If one and only one match is found then | |||
| the instantiation is successful and the new object will be configured; | |||
| otherwise it is an error and parsing stops. | |||
| </p> | |||
| <br/> | |||
| </li> | |||
| <li> | |||
| <p> | |||
| The configured object may or may not implement the Role interface, | |||
| if it does not, an Adaptor object may be instantiated as a proxy | |||
| for the object. Which adaptor is used depends on how the implementation | |||
| was declared. | |||
| </p> | |||
| <br/> | |||
| </li> | |||
| <li> | |||
| <p> | |||
| The resulting object is passed as an argument to the addConfigured() method. | |||
| </p> | |||
| <br/> | |||
| </li> | |||
| </ol> | |||
| </subsection> | |||
| <subsection name="Declaration of roles"> | |||
| <p> | |||
| A role definition associates a name with an (Interface,Adaptor) pair. | |||
| The only reason for associating a name with the role is to ease notation when | |||
| declaring members of a role. | |||
| </p> | |||
| <br/> | |||
| <p> | |||
| Notice that the same interface or the same Adaptor may appear in multiple | |||
| declarations. This only means that depending on the name used the adaptor | |||
| of choice will be different. | |||
| </p> | |||
| <br/> | |||
| <p> | |||
| There can only be one pair associated with each name. | |||
| </p> | |||
| <br/> | |||
| </subsection> | |||
| <subsection name="Declaration of implementations (members)"> | |||
| <br/> | |||
| <p> | |||
| A class is declared as belonging to a role by specifying the name to be used | |||
| when appearing in that role. The same class may belong to multiple roles | |||
| and may specify the same or different names on each one. | |||
| <br/> | |||
| </p> | |||
| <p> | |||
| The name used for the role during the declaration only determines which | |||
| Adaptor will be available, if required. | |||
| <br/> | |||
| </p> | |||
| <p> | |||
| Within a role-interface there can only be one object associated | |||
| with each name. | |||
| <br/> | |||
| </p> | |||
| </subsection> | |||
| <subsection name="Scoping rules"> | |||
| <br/> | |||
| <p> | |||
| This is probably the more dificult aspect since given the way | |||
| <ant> and <antcall> work it means possible redeclarations on every | |||
| level of recursion. Whether declarations should just supercede | |||
| one another or be smarter is something to look into. | |||
| <br/> | |||
| </p> | |||
| </subsection> | |||
| <subsection name="Syntax"> | |||
| <br/> | |||
| <p> | |||
| I have left out the issues of how the syntax looks like on purpose. | |||
| <br/> | |||
| </p> | |||
| <p> | |||
| Syntax is just that and I am sure we can reach agreement somehow. | |||
| It is also clear that we should provide tasks to define roles | |||
| and declare members of roles direclty on the build. | |||
| <br/> | |||
| </p> | |||
| </subsection> | |||
| </section> | |||
| <section name="Making ant aware of tag/role/class associations"> | |||
| <p> | |||
| The antlib proposal says : | |||
| Let's declare explicitly that a tag can be used in a particular role and is implemented by a specific class. | |||
| The declaration happens inside antlibs in the file META-INF/antlib.xml | |||
| </p> | |||
| Example : | |||
| <source><![CDATA[ | |||
| <filter name="escapeunicode" class="org.apache.tools.ant.filters.EscapeUnicode"/> | |||
| ]]></source> | |||
| <p> | |||
| CM says : | |||
| A normal typedef is enough to make ant aware of the existence of the class org.apache.tools.ant.filters.EscapeUnicode. | |||
| Due to the fact that EscapeUnicode implements ChainableReader, the association between EscapeUnicode and the filter role does not need to be stated explicitly. | |||
| </p> | |||
| </section> | |||
| <section name="Method names in parent classes supporting roles"> | |||
| <p> | |||
| There is a discussion about how methods to add nested elements of a specific roles in a parent class should be called, and what their signature should be like. | |||
| </p> | |||
| <p> | |||
| CM : | |||
| <source> | |||
| addTYPE(TYPE) | |||
| </source> | |||
| for instance <source>addChainableReader(ChainableReader a)</source> | |||
| </p> | |||
| <p> | |||
| PR: | |||
| to add an element before its own attributes and nested elements are configured. | |||
| <source> | |||
| void add(TYPE) | |||
| </source> | |||
| to add an already configured element | |||
| <source> | |||
| void addConfigured(TYPE) | |||
| </source> | |||
| </p> | |||
| <p> | |||
| in the ant code of 1.6 : | |||
| <source>public Object createDynamicElement(String name)</source> | |||
| </p> | |||
| </section> | |||
| <section name="Cardinality problems"> | |||
| <subsection name="One tag, several implementations"> | |||
| <p> | |||
| The <weblogic> element in <ejbjar>, <jspc>, <serverdeploy>, has different meanings. | |||
| </p> | |||
| <p> | |||
| This is an argument to introduce roles in ant, and to associate an XML tag with a role and an implementation class. | |||
| </p> | |||
| </subsection> | |||
| <subsection name="Parent classes accepting one interface in different functions"> | |||
| <p> | |||
| As an example, the dependset task accepts nested filesets for two different functions : | |||
| <ul> | |||
| <li>source</li> | |||
| <li>target</li> | |||
| </ul> | |||
| </p> | |||
| <p>Stefan Bodewig/Costin Manolache suggest :</p> | |||
| <source><![CDATA[ | |||
| <dependset> | |||
| <zipfileset ant:type="srcfileset"> | |||
| </dependset> | |||
| ]]></source> | |||
| </subsection> | |||
| <subsection name="adapters"> | |||
| <p> | |||
| The antlib proposal mentions adapter classes, which would be connected to roles. | |||
| Costin Manolache says that adapter classes should be tied to components, not roles. | |||
| The reason : two different components implementing the same interface (AKA role) can require different adapters. | |||
| </p> | |||
| </subsection> | |||
| </section> | |||
| <section name="role proposal"> | |||
| <p> | |||
| slightly modified version of something writte by Jose Alberto Fernandez | |||
| </p> | |||
| <source><![CDATA[ | |||
| <role name="roleName" className="...." [adapter="...."] /> | |||
| <!-- I have added the possibility to declare a specific adapter per component to take into account what Costin said --> | |||
| <component name="elementName" role="roleName" className="....." [adapter="...."] /> | |||
| ]]></source> | |||
| </section> | |||
| </body> | |||
| </document> | |||