Add in proposals for replacement of the Avalon Configuration system

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@271941 13f79535-47bb-0310-9956-ffa450edef68

proposal/myrmidon/src/java/org/apache/myrmidon/api/metadata/ModelElement.java

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+/*
+ * Copyright (C) The Apache Software Foundation. All rights reserved.
+ *
+ * This software is published under the terms of the Apache Software License
+ * version 1.1, a copy of which has been included  with this distribution in
+ * the LICENSE.txt file.
+ */
+package org.apache.myrmidon.api.metadata;
+
+/**
+ * A ModelElement represents the data necessary to configure
+ * the task or sub-object. It usually represents an XML element in a
+ * build file and has similar features to XML elements.
+ *
+ * <p>It has a set of un-ordered attributes with each attribute mapping
+ * a key to a value. The ModelElement can also have either a set of ordered
+ * sub-elements or text content (one or the other - not both).</p>
+ *
+ * @author <a href="mailto:peter@apache.org">Peter Donald</a>
+ * @version $Revision$ $Date$
+ */
+public class ModelElement
+{
+    /**
+     * Return an array containing all the child <code>ModelElement</code>s
+     * that are contained within this <code>ModelElement</code>. If this method
+     * returns an array containing 1 or more elements then it must return null
+     * for getContent() method.
+     *
+     * @todo determine whether we return null or an empty array when no
+     *       child elements.
+     * @return all the child <code>ModelElement</code>s
+     * @see #getContent()
+     */
+    public ModelElement[] getChildren()
+    {
+        return null;
+    }
+
+    /**
+     * Return an array containing the names of all the attributes stored
+     * in this <code>ModelElement</code>. The user can then pass these
+     * parameters into the getAttribute() method of this class to get the
+     * value of the attribute.
+     *
+     * @return an array of the attribute names
+     * @see #getAttribute(String)
+     */
+    public String[] getAttributeNames()
+    {
+        return null;
+    }
+
+    /**
+     * Get the value of the attribute passed in.
+     * If no such attribute exists return null.
+     *
+     * @param name the name of the attribute to retrieve value for
+     * @return the value of the attribute with specified name or null
+     *         if no such element.
+     */
+    public String getAttribute( final String name )
+    {
+        return null;
+    }
+
+    /**
+     * Retrieve the content of this element if any. Will return
+     * null if no content available. Note it is invalid for this
+     * method to return a non-null value and the getChildren()
+     * method to return an array of 1 or more child elements.
+     *
+     * @return the content value if any, else null
+     * @see #getChildren()
+     */
+    public String getContent()
+    {
+        return null;
+    }
+}

proposal/myrmidon/src/java/org/apache/myrmidon/api/metadata/Modeller.java

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+/*
+ * Copyright (C) The Apache Software Foundation. All rights reserved.
+ *
+ * This software is published under the terms of the Apache Software License
+ * version 1.1, a copy of which has been included  with this distribution in
+ * the LICENSE.txt file.
+ */
+package org.apache.myrmidon.api.metadata;
+
+/**
+ * The Modeller interface specifies that the implementing object
+ * wishes to handle its own configuration stage. In which case the
+ * object is passed the ModelElement representing itself and it uses
+ * the element to configure itself.
+ *
+ * @author <a href="mailto:peter@apache.org">Peter Donald</a>
+ * @version $Revision$ $Date$
+ * @see ModelElement
+ */
+public interface Modeller
+{
+    /**
+     * Pass the object a read-only instance of it's own
+     * model.
+     *
+     * @param element the ModelElement representing object
+     */
+    void model( ModelElement element );
+}