--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/api/evalexpr/CompileFromString.java Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,127 @@
+/*
+ * Copyright 2005-2006 Sun Microsystems, Inc. All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code 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
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package evalexpr;
+
+import java.lang.reflect.Method;
+import java.util.*;
+import javax.swing.JOptionPane;
+import javax.tools.*;
+import static javax.tools.StandardLocation.CLASS_OUTPUT;
+
+/**
+ * JSR 199 Demo application: compile from a String.
+ *
+ * <p><b>This is NOT part of any API supported by Sun Microsystems.
+ * If you write code that depends on this, you do so at your own
+ * risk. This code and its internal interfaces are subject to change
+ * or deletion without notice.</b></p>
+ *
+ * @author Peter von der Ahé
+ */
+public class CompileFromString {
+
+ /**
+ * The name of the class used to evaluate expressions.
+ */
+ private final static String CLASS_NAME = "EvalExpression";
+
+ /**
+ * Object used to signal errors from evalExpression.
+ */
+ public final static Object ERROR = new Object() {
+ public String toString() { return "error"; }
+ };
+
+ /**
+ * Compile and evaluate the specified expression using the
+ * given compiler.
+ * @param compiler a JSR 199 compiler tool used to compile the given expression
+ * @param expression a Java Programming Language expression
+ * @return the value of the expression; ERROR if any errors occured during compilation
+ * @throws java.lang.Exception exceptions are ignored for brevity
+ */
+ public static Object evalExpression(JavaCompiler compiler,
+ DiagnosticListener<JavaFileObject> listener,
+ List<String> flags,
+ String expression)
+ throws Exception
+ {
+ // Use a customized file manager
+ MemoryFileManager mfm =
+ new MemoryFileManager(compiler.getStandardFileManager(listener, null, null));
+
+ // Create a file object from a string
+ JavaFileObject fileObject = mfm.makeSource(CLASS_NAME,
+ "public class " + CLASS_NAME + " {\n" +
+ " public static Object eval() throws Throwable {\n" +
+ " return " + expression + ";\n" +
+ " }\n}\n");
+
+ JavaCompiler.CompilationTask task =
+ compiler.getTask(null, mfm, listener, flags, null, Arrays.asList(fileObject));
+ if (task.call()) {
+ // Obtain a class loader for the compiled classes
+ ClassLoader cl = mfm.getClassLoader(CLASS_OUTPUT);
+ // Load the compiled class
+ Class compiledClass = cl.loadClass(CLASS_NAME);
+ // Find the eval method
+ Method eval = compiledClass.getMethod("eval");
+ // Invoke it
+ return eval.invoke(null);
+ } else {
+ // Report that an error occured
+ return ERROR;
+ }
+ }
+
+ /**
+ * Main entry point for program; ask user for expressions,
+ * compile, evaluate, and print them.
+ *
+ * @param args ignored
+ * @throws java.lang.Exception exceptions are ignored for brevity
+ */
+ public static void main(String... args) throws Exception {
+ // Get a compiler tool
+ final JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
+ final List<String> compilerFlags = new ArrayList();
+ compilerFlags.add("-Xlint:all"); // report all warnings
+ compilerFlags.add("-g:none"); // don't generate debug info
+ String expression = "System.getProperty(\"java.vendor\")";
+ while (true) {
+ expression = JOptionPane.showInputDialog("Please enter a Java expression",
+ expression);
+ if (expression == null)
+ return; // end program on "cancel"
+ long time = System.currentTimeMillis();
+ Object result = evalExpression(compiler, null, compilerFlags, expression);
+ time = System.currentTimeMillis() - time;
+ System.out.format("Elapsed time %dms %n", time);
+ if (result == ERROR)
+ System.out.format("Error compiling \"%s\"%n", expression);
+ else
+ System.out.format("%s => %s%n", expression, result);
+ }
+ }
+}