| /* |
| * Copyright (c) 2013, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package com.oracle.java.testlibrary; |
| |
| import java.io.ByteArrayOutputStream; |
| import java.io.IOException; |
| import java.io.OutputStream; |
| |
| import java.net.URI; |
| import java.util.Arrays; |
| |
| import javax.tools.ForwardingJavaFileManager; |
| import javax.tools.ForwardingJavaFileManager; |
| import javax.tools.FileObject; |
| import javax.tools.JavaCompiler; |
| import javax.tools.JavaCompiler.CompilationTask; |
| import javax.tools.JavaFileManager; |
| import javax.tools.JavaFileObject; |
| import javax.tools.JavaFileObject.Kind; |
| import javax.tools.SimpleJavaFileObject; |
| import javax.tools.ToolProvider; |
| |
| /** |
| * {@code InMemoryJavaCompiler} can be used for compiling a {@link |
| * CharSequence} to a {@code byte[]}. |
| * |
| * The compiler will not use the file system at all, instead using a {@link |
| * ByteArrayOutputStream} for storing the byte code. For the source code, any |
| * kind of {@link CharSequence} can be used, e.g. {@link String}, {@link |
| * StringBuffer} or {@link StringBuilder}. |
| * |
| * The {@code InMemoryCompiler} can easily be used together with a {@code |
| * ByteClassLoader} to easily compile and load source code in a {@link String}: |
| * |
| * <pre> |
| * {@code |
| * import com.oracle.java.testlibrary.InMemoryJavaCompiler; |
| * import com.oracle.java.testlibrary.ByteClassLoader; |
| * |
| * class Example { |
| * public static void main(String[] args) { |
| * String className = "Foo"; |
| * String sourceCode = "public class " + className + " {" + |
| * " public void bar() {" + |
| * " System.out.println("Hello from bar!");" + |
| * " }" + |
| * "}"; |
| * byte[] byteCode = InMemoryJavaCompiler.compile(className, sourceCode); |
| * Class fooClass = ByteClassLoader.load(className, byteCode); |
| * } |
| * } |
| * } |
| * </pre> |
| */ |
| public class InMemoryJavaCompiler { |
| private static class MemoryJavaFileObject extends SimpleJavaFileObject { |
| private final String className; |
| private final CharSequence sourceCode; |
| private final ByteArrayOutputStream byteCode; |
| |
| public MemoryJavaFileObject(String className, CharSequence sourceCode) { |
| super(URI.create("string:///" + className.replace('.','/') + Kind.SOURCE.extension), Kind.SOURCE); |
| this.className = className; |
| this.sourceCode = sourceCode; |
| this.byteCode = new ByteArrayOutputStream(); |
| } |
| |
| @Override |
| public CharSequence getCharContent(boolean ignoreEncodingErrors) { |
| return sourceCode; |
| } |
| |
| @Override |
| public OutputStream openOutputStream() throws IOException { |
| return byteCode; |
| } |
| |
| public byte[] getByteCode() { |
| return byteCode.toByteArray(); |
| } |
| |
| public String getClassName() { |
| return className; |
| } |
| } |
| |
| private static class FileManagerWrapper extends ForwardingJavaFileManager { |
| private MemoryJavaFileObject file; |
| |
| public FileManagerWrapper(MemoryJavaFileObject file) { |
| super(getCompiler().getStandardFileManager(null, null, null)); |
| this.file = file; |
| } |
| |
| @Override |
| public JavaFileObject getJavaFileForOutput(Location location, String className, |
| Kind kind, FileObject sibling) |
| throws IOException { |
| if (!file.getClassName().equals(className)) { |
| throw new IOException("Expected class with name " + file.getClassName() + |
| ", but got " + className); |
| } |
| return file; |
| } |
| } |
| |
| /** |
| * Compiles the class with the given name and source code. |
| * |
| * @param className The name of the class |
| * @param sourceCode The source code for the class with name {@code className} |
| * @throws RuntimeException if the compilation did not succeed |
| * @return The resulting byte code from the compilation |
| */ |
| public static byte[] compile(String className, CharSequence sourceCode) { |
| MemoryJavaFileObject file = new MemoryJavaFileObject(className, sourceCode); |
| CompilationTask task = getCompilationTask(file); |
| |
| if(!task.call()) { |
| throw new RuntimeException("Could not compile " + className + " with source code " + sourceCode); |
| } |
| |
| return file.getByteCode(); |
| } |
| |
| private static JavaCompiler getCompiler() { |
| return ToolProvider.getSystemJavaCompiler(); |
| } |
| |
| private static CompilationTask getCompilationTask(MemoryJavaFileObject file) { |
| return getCompiler().getTask(null, new FileManagerWrapper(file), null, null, null, Arrays.asList(file)); |
| } |
| } |