Initial revision

From-SVN: r102074

libjava/classpath/gnu/java/beans/decoder/VoidHandler.java

@@ -0,0 +1,140 @@
+/* gnu.java.beans.decoder.VoidHandler
+   Copyright (C) 2004 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+ 
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+package gnu.java.beans.decoder;
+
+import java.beans.ExceptionListener;
+
+import org.xml.sax.Attributes;
+
+public class VoidHandler extends AbstractElementHandler
+{
+    /**
+     * @param PersistenceParser
+     */
+    VoidHandler(ElementHandler parent)
+    {
+        super(parent, true);
+    }
+
+    protected Context startElement(
+        Attributes attributes,
+        ExceptionListener exceptionListener)
+        throws AssemblyException
+    {
+        Context ctx = startElementImpl(attributes);
+        ctx.setStatement(true);
+
+        return ctx;
+    }
+
+    private Context startElementImpl(Attributes attributes)
+        throws AssemblyException
+    {
+        String id = attributes.getValue("id");
+        String className = attributes.getValue("class");
+        String methodName = attributes.getValue("method");
+        String propertyName = attributes.getValue("property");
+        String index = attributes.getValue("index");
+
+        if (className != null)
+        {
+            try
+            {
+                Class klass = instantiateClass(className);
+
+                // class name exists which means that we are in a static context.
+                // so we may want to ...
+                // run a constructor if methodName is "new" or null
+                if (methodName == null || methodName.equals("new"))
+                    // if the id is null the result cannot be by the decoder accessed but the
+                    // constructor may have side effects (e.g. registering itself in a global registry)
+                    return new ConstructorContext(id, klass);
+
+                // (falling through is important!)
+                // run a static method on the given class (if methodName exists, which is implied already) 
+                return new StaticMethodContext(id, klass, methodName);
+            }
+            catch (ClassNotFoundException cnfe)
+            {
+                throw new AssemblyException(cnfe);
+            }
+        }
+        else
+        {
+            // className does not exist which means we are in the context of
+            // some object and want to ...
+            // access an element by index
+            if (index != null)
+            {
+                // note: whether this resolves into get(i) or set(i, o) depends on the
+                // number of arguments and is decided by the ObjectAssembler
+                try
+                {
+                    return new IndexContext(id, Integer.parseInt(index));
+                }
+                catch (NumberFormatException nfe)
+                {
+                    throw new AssemblyException(nfe);
+                }
+            }
+
+            // access a method if methodName exists
+            if (methodName != null)
+                return new MethodContext(id, methodName);
+
+            // (falling through is important!)
+            // access a property if a propertyName exists
+            if (propertyName != null && propertyName.length() > 0)
+                // this is reported as an ordinary method invocation where the propertyName is
+                // converted into a 'setter'-method name: convert first character of property name
+                // to upper case and prepend 'set'
+                // Note: This will be a setter-method because the <void> tag implies that no return
+                // value is expected (but a side effect)
+                return new PropertyContext(id, propertyName);
+        }
+
+        // if code reaches this point the tag has wrong attributes. The following test
+        // does not make it better but can provide are more specific error message for
+        // a common mistake: <void> tags are not allowed to have an idref attribute
+        throw new AssemblyException(
+            new IllegalArgumentException(
+                (attributes.getValue("idref") == null)
+                    ? "Missing attributes for <void> tag"
+                    : "<void> does not support 'idref' attribute."));
+    }
+}