Generalize velocity creation and classloader setting for code generation ant tasks into GenTask

git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@6109 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/presents/tools/GenDObjectTask.java

@@ -31,22 +31,14 @@ import java.util.ArrayList;
 import java.io.File;
 import java.io.StringWriter;
 
-import org.apache.tools.ant.AntClassLoader;
 import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.DirectoryScanner;
-import org.apache.tools.ant.Task;
 import org.apache.tools.ant.types.FileSet;
-import org.apache.tools.ant.types.Reference;
-import org.apache.tools.ant.util.ClasspathUtils;
 import org.apache.velocity.VelocityContext;
-import org.apache.velocity.app.VelocityEngine;
-
 import com.google.common.collect.Lists;
 
 import com.samskivert.util.StringUtil;
 
-import com.samskivert.velocity.VelocityUtil;
-
 import com.threerings.presents.annotation.TransportHint;
 import com.threerings.presents.dobj.DObject;
 import com.threerings.presents.dobj.DSet;
@@ -55,7 +47,7 @@ import com.threerings.presents.dobj.OidList;
 /**
  * Generates necessary additional distributed object declarations and methods.
  */
-public class GenDObjectTask extends Task
+public class GenDObjectTask extends GenTask
 {
     /**
      * Adds a nested <fileset> element which enumerates service declaration source files.
@@ -65,41 +57,13 @@ public class GenDObjectTask extends Task
         _filesets.add(set);
     }
 
-    /** Configures our classpath which we'll use to load service classes. */
-    public void setClasspathref (Reference pathref)
-    {
-        _cloader = ClasspathUtils.getClassLoaderForPath(getProject(), pathref);
-
-        // set the parent of the classloader to be the classloader used to load this task,
-        // rather than the classloader used to load Ant, so that we have access to Narya
-        // classes like TransportHint
-        ((AntClassLoader)_cloader).setParent(getClass().getClassLoader());
-    }
-
     @Override
     public void execute ()
     {
-        if (_cloader == null) {
-            String errmsg = "This task requires a 'classpathref' attribute " +
-                "to be set to the project's classpath.";
-            throw new BuildException(errmsg);
-        }
-
-        try {
-            _velocity = VelocityUtil.createEngine();
-        } catch (Exception e) {
-            throw new BuildException("Failure initializing Velocity", e);
-        }
-
         // resolve the DObject class using our classloader
-        try {
+        _doclass = loadClass(DObject.class.getName());
-            _doclass = _cloader.loadClass(DObject.class.getName());
+        _dsclass = loadClass(DSet.class.getName());
-            _dsclass = _cloader.loadClass(DSet.class.getName());
+        _olclass = loadClass(OidList.class.getName());
-            _olclass = _cloader.loadClass(OidList.class.getName());
-
-        } catch (Exception e) {
-            throw new BuildException("Can't resolve InvocationListener", e);
-        }
 
         for (FileSet fs : _filesets) {
             DirectoryScanner ds = fs.getDirectoryScanner(getProject());
@@ -116,17 +80,12 @@ public class GenDObjectTask extends Task
     {
         // load up the file and determine it's package and classname
         String name = null;
+        Class<?> klass = loadClass(name);
         try {
-            // System.err.println("Processing " + source + "...");
             name = GenUtil.readClassName(source);
-            processObject(source, _cloader.loadClass(name));
+            processObject(source, klass);
-        } catch (ClassNotFoundException cnfe) {
-            System.err.println("Failed to load " + name + ".\n" +
-                               "Missing class: " + cnfe.getMessage());
-            System.err.println("Be sure to set the 'classpathref' attribute to a classpath\n" +
-                               "that contains your projects invocation service classes.");
         } catch (Exception e) {
-            throw new BuildException("Failed to process " + source.getName() + ": " + e, e);
+            throw new BuildException("Failed to process " + source.getName(), e);
         }
     }
 
@@ -248,12 +207,6 @@ public class GenDObjectTask extends Task
     /** A list of filesets that contain tile images. */
     protected ArrayList<FileSet> _filesets = Lists.newArrayList();
 
-    /** Used to do our own classpath business. */
-    protected ClassLoader _cloader;
-
-    /** Used to generate source files from templates. */
-    protected VelocityEngine _velocity;
-
     /** {@link DObject} resolved with the proper classloader so that we
      * can compare it to loaded derived classes. */
     protected Class<?> _doclass;

src/java/com/threerings/presents/tools/GenTask.java

@@ -0,0 +1,66 @@
+package com.threerings.presents.tools;
+
+import org.apache.tools.ant.AntClassLoader;
+import org.apache.tools.ant.BuildException;
+import org.apache.tools.ant.Task;
+import org.apache.tools.ant.types.Reference;
+import org.apache.tools.ant.util.ClasspathUtils;
+import org.apache.velocity.app.VelocityEngine;
+
+import com.samskivert.velocity.VelocityUtil;
+
+public abstract class GenTask extends Task
+{
+    public GenTask ()
+    {
+        try {
+            _velocity = VelocityUtil.createEngine();
+        } catch (Exception e) {
+            throw new BuildException("Failure initializing Velocity", e);
+        }
+    }
+
+    /**
+     * Configures to output extra information when generating code.
+     */
+    public void setVerbose (boolean verbose)
+    {
+        _verbose = verbose;
+    }
+
+    /** Configures our classpath which we'll use to load service classes. */
+    public void setClasspathref (Reference pathref)
+    {
+        _cloader = ClasspathUtils.getClassLoaderForPath(getProject(), pathref);
+
+        // set the parent of the classloader to be the classloader used to load this task, rather
+        // than the classloader used to load Ant, so that we have access to Narya classes like
+        // TransportHint
+        ((AntClassLoader)_cloader).setParent(getClass().getClassLoader());
+    }
+
+    protected Class<?> loadClass (String name)
+    {
+        if (_cloader == null) {
+            throw new BuildException("This task requires a 'classpathref' attribute " +
+                "to be set to the project's classpath.");
+        }
+        try {
+            return _cloader.loadClass(name);
+        } catch (ClassNotFoundException cnfe) {
+            throw new BuildException(
+                "Failed to load " + name + ".  Be sure to set the 'classpathref' attribute to a " +
+                "classpath that contains your project's presents classes.", cnfe);
+        }
+    }
+
+    /** Show extra output if set. */
+    protected boolean _verbose;
+
+    /** Used to do our own classpath business. */
+    protected ClassLoader _cloader;
+
+    /** Used to generate source files from templates. */
+    protected VelocityEngine _velocity;
+
+}

src/java/com/threerings/presents/tools/InvocationTask.java

@@ -35,15 +35,9 @@ import java.io.FileReader;
 import java.io.IOException;
 import java.io.PrintWriter;
 
-import org.apache.tools.ant.AntClassLoader;
 import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.DirectoryScanner;
-import org.apache.tools.ant.Task;
 import org.apache.tools.ant.types.FileSet;
-import org.apache.tools.ant.types.Reference;
-import org.apache.tools.ant.util.ClasspathUtils;
-import org.apache.velocity.app.VelocityEngine;
-
 import com.google.common.base.Predicate;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Lists;
@@ -51,8 +45,6 @@ import com.google.common.collect.Lists;
 import com.samskivert.io.StreamUtil;
 import com.samskivert.util.Logger;
 import com.samskivert.util.StringUtil;
-import com.samskivert.velocity.VelocityUtil;
-
 import com.threerings.presents.annotation.TransportHint;
 import com.threerings.presents.net.Transport;
 import com.threerings.presents.client.InvocationService.InvocationListener;
@@ -61,7 +53,7 @@ import com.threerings.presents.client.InvocationService.InvocationListener;
  * A base Ant task for generating invocation service related marshalling
  * and unmarshalling classes.
  */
-public abstract class InvocationTask extends Task
+public abstract class InvocationTask extends GenTask
 {
     /** Used to keep track of invocation service method listener arguments. */
     public class ListenerArgument
@@ -371,46 +363,11 @@ public abstract class InvocationTask extends Task
         }
     }
 
-    /**
-     * Configures to output extra information when generating code.
-     */
-    public void setVerbose (boolean verbose)
-    {
-        _verbose = verbose;
-    }
-
-    /** Configures our classpath which we'll use to load service classes. */
-    public void setClasspathref (Reference pathref)
-    {
-        _cloader = ClasspathUtils.getClassLoaderForPath(getProject(), pathref);
-
-        // set the parent of the classloader to be the classloader used to load this task, rather
-        // than the classloader used to load Ant, so that we have access to Narya classes like
-        // TransportHint
-        ((AntClassLoader)_cloader).setParent(getClass().getClassLoader());
-    }
-
     @Override
     public void execute ()
     {
-        if (_cloader == null) {
-            String errmsg = "This task requires a 'classpathref' attribute " +
-                "to be set to the project's classpath.";
-            throw new BuildException(errmsg);
-        }
-
-        try {
-            _velocity = VelocityUtil.createEngine();
-        } catch (Exception e) {
-            throw new BuildException("Failure initializing Velocity", e);
-        }
-
         // resolve the InvocationListener class using our classloader
-        try {
+        _ilistener = loadClass(InvocationListener.class.getName());
-            _ilistener = _cloader.loadClass(InvocationListener.class.getName());
-        } catch (Exception e) {
-            throw new BuildException("Can't resolve InvocationListener", e);
-        }
 
         for (FileSet fs : _filesets) {
             DirectoryScanner ds = fs.getDirectoryScanner(getProject());
@@ -434,13 +391,9 @@ public abstract class InvocationTask extends Task
             throw new BuildException("Failed to parse " + source + ": " + e.getMessage());
         }
 
+        Class<?> serviceClass = loadClass(name);
         try {
-            processService(source, _cloader.loadClass(name));
+            processService(source, serviceClass);
-        } catch (ClassNotFoundException cnfe) {
-            System.err.println("Failed to load " + name + ".\n" +
-                               "Missing class: " + cnfe.getMessage());
-            System.err.println("Be sure to set the 'classpathref' attribute to a classpath\n" +
-                               "that contains your projects invocation service classes.");
         } catch (Exception e) {
             throw new BuildException("Failed to process " + source.getName() + ": " + e, e);
         }
@@ -480,15 +433,6 @@ public abstract class InvocationTask extends Task
     /** A header to put on all generated source files. */
     protected String _header;
 
-    /** Show extra output if set. */
-    protected boolean _verbose;
-
-    /** Used to do our own classpath business. */
-    protected ClassLoader _cloader;
-
-    /** Used to generate source files from templates. */
-    protected VelocityEngine _velocity;
-
     /** {@link InvocationListener} resolved with the proper classloader so
      * that we can compare it to loaded derived classes. */
     protected Class<?> _ilistener;