Added in sketch of new item set type approach which is generalisation of current system.

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@268706 13f79535-47bb-0310-9956-ffa450edef68

proposal/myrmidon/src/java/org/apache/ant/util/ItemSet.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 file.
+ */
+package org.apache.ant.util;
+
+import org.apache.ant.tasklet.DataType;
+
+/**
+ * Interface for ItemSet.
+ * An item set contains a number of items. Example item sets include
+ * PatternSets, FileSets, FilterSets etc.
+ *
+ * @author <a href="mailto:donaldp@apache.org">Peter Donald</a>
+ */
+public interface ItemSet
+    extends DataType
+{
+    /**
+     * Returns an array containing the items(s) contained within set.
+     * 
+     * Question: should ItemSet be context sensitive????
+     */
+    Object[] getItems( /* Context context??? */ );
+}

proposal/myrmidon/src/java/org/apache/ant/util/Mapper.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 file.
+ */
+package org.apache.ant.util;
+
+import org.apache.ant.tasklet.DataType;
+
+/**
+ * Interface for Mappers.
+ * Mappers are responsible for mapping source items to targets items.
+ * Example mappers will map source files to destination files 
+ * (ie A.java to A.class).
+ *
+ * @author <a href="mailto:donaldp@apache.org">Peter Donald</a>
+ * @author <a href="mailto:stefan.bodewig@epost.de">Stefan Bodewig</a>
+ */
+public interface Mapper
+    extends DataType
+{
+    /**
+     * Returns an array containing the target items(s) for the
+     * given source file.
+     *
+     * <p>if the given rule doesn't apply to the input item,
+     * implementation must return null. Scanner will then
+     * omit the item in question.</p> 
+     *
+     * @param item the item to be mapped
+     */
+    Object[] mapItem( Object item );
+}

proposal/myrmidon/src/java/org/apache/ant/util/Scanner.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 file.
+ */
+package org.apache.ant.util;
+
+import org.apache.avalon.Component;
+
+/**
+ * Interface for Scanners.
+ *
+ * @author <a href="mailto:donaldp@apache.org">Peter Donald</a>
+ */
+public interface Scanner
+    extends Component
+{
+}