| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.drill.exec.expr.fn; |
| |
| import java.io.StringWriter; |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| import org.codehaus.commons.compiler.CompileException; |
| import org.codehaus.janino.Java; |
| import org.codehaus.janino.Java.AbstractClassDeclaration; |
| import org.codehaus.janino.Java.MethodDeclarator; |
| import org.codehaus.janino.Unparser; |
| import org.codehaus.janino.util.AbstractTraverser; |
| import org.codehaus.janino.util.DeepCopier; |
| |
| public class MethodGrabbingVisitor { |
| |
| private final Class<?> clazz; |
| private final Map<String, String> methods = new HashMap<>(); |
| private final ClassFinder classFinder = new ClassFinder(); |
| private boolean captureMethods = false; |
| |
| private MethodGrabbingVisitor(Class<?> clazz) { |
| this.clazz = clazz; |
| } |
| |
| /** |
| * Creates a map with all method names and their modified bodies |
| * from specified {@link Java.CompilationUnit}. |
| * |
| * @param compilationUnit the source of the methods to collect |
| * @param clazz type of the class to handle |
| * @return a map with all method names and their modified bodies. |
| */ |
| public static Map<String, String> getMethods(Java.CompilationUnit compilationUnit, Class<?> clazz) { |
| MethodGrabbingVisitor visitor = new MethodGrabbingVisitor(clazz); |
| visitor.classFinder.visitTypeDeclaration(compilationUnit.getPackageMemberTypeDeclarations()[0]); |
| return visitor.methods; |
| } |
| |
| public class ClassFinder extends AbstractTraverser<RuntimeException> { |
| |
| @Override |
| public void traverseClassDeclaration(AbstractClassDeclaration classDeclaration) { |
| boolean prevCapture = captureMethods; |
| captureMethods = clazz.getName().equals(classDeclaration.getClassName()); |
| super.traverseClassDeclaration(classDeclaration); |
| captureMethods = prevCapture; |
| } |
| |
| @Override |
| public void traverseMethodDeclarator(MethodDeclarator methodDeclarator) { |
| if (captureMethods) { |
| // Generates a "labeled statement". |
| // This code takes code from the method body, wraps it into the labeled statement |
| // and replaces all the return statements by break command with label. |
| // |
| // For example, the following method |
| // public void foo(int a) { |
| // if (a < 0) { |
| // return; |
| // } else { |
| // do something; |
| // } |
| // } |
| // |
| // will be converted to |
| // MethodClassName_foo: { |
| // if (a < 0) { |
| // break MethodClassName_foo; |
| // } else { |
| // do something; |
| // } |
| // } |
| |
| // Constructs a name of the resulting label |
| // using methods class name and method name itself. |
| String[] fQCN = methodDeclarator.getDeclaringType().getClassName().split("\\."); |
| String returnLabel = fQCN[fQCN.length - 1] + "_" + methodDeclarator.name; |
| Java.Block methodBodyBlock = new Java.Block(methodDeclarator.getLocation()); |
| |
| // DeepCopier implementation which returns break statement with label |
| // instead if return statement. |
| DeepCopier returnStatementReplacer = new DeepCopier() { |
| @Override |
| public Java.BlockStatement copyReturnStatement(Java.ReturnStatement subject) { |
| return new Java.BreakStatement(subject.getLocation(), returnLabel); |
| } |
| }; |
| try { |
| // replaces return statements and stores the result into methodBodyBlock |
| methodBodyBlock.addStatements( |
| returnStatementReplacer.copyBlockStatements(methodDeclarator.statements)); |
| } catch (CompileException e) { |
| throw new RuntimeException(e); |
| } |
| |
| // wraps method code with replaced return statements into label statement. |
| Java.LabeledStatement labeledStatement = |
| new Java.LabeledStatement(methodDeclarator.getLocation(), returnLabel, methodBodyBlock); |
| |
| // Unparse the labeled statement. |
| StringWriter writer = new StringWriter(); |
| Unparser unparser = new Unparser(writer); |
| // unparses labeledStatement and stores unparsed code into writer |
| unparser.unparseBlockStatement(labeledStatement); |
| unparser.close(); |
| writer.flush(); |
| methods.put(methodDeclarator.name, writer.getBuffer().toString()); |
| } |
| } |
| } |
| |
| } |