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
2010-08-10 00:38:46 +00:00
parent 1236121ff6
commit 4ea22628f7
3 changed files with 77 additions and 114 deletions
@@ -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;
+
+}