1 #// Usage: jjs exceptionswallow.js -- <directory> 2 3 /* 4 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 10 * - Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 13 * - Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * - Neither the name of Oracle nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS 22 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 23 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 25 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 26 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 27 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 28 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 29 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 30 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 31 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 // This example demonstrates Java subclassing by Java.extend 35 // and javac Compiler and Tree API. This example looks for 36 // empty catch blocks ("exception swallow") and reports those. 37 38 if (arguments.length == 0) { 39 print("Usage: jjs exceptionswallow.js -- <directory>"); 40 exit(1); 41 } 42 43 // Java types used 44 var File = Java.type("java.io.File"); 45 var Files = Java.type("java.nio.file.Files"); 46 var StringArray = Java.type("java.lang.String[]"); 47 var ToolProvider = Java.type("javax.tools.ToolProvider"); 48 var Tree = Java.type("com.sun.source.tree.Tree"); 49 var EmptyStatementTree = Java.type("com.sun.source.tree.EmptyStatementTree"); 50 var Trees = Java.type("com.sun.source.util.Trees"); 51 var TreeScanner = Java.type("com.sun.source.util.TreeScanner"); 52 53 // printEmptyCatch 54 55 function printEmptyCatch() { 56 // get the system compiler tool 57 var compiler = ToolProvider.systemJavaCompiler; 58 // get standard file manager 59 var fileMgr = compiler.getStandardFileManager(null, null, null); 60 // Using Java.to convert script array (arguments) to a Java String[] 61 var compUnits = fileMgr.getJavaFileObjects( 62 Java.to(arguments, StringArray)); 63 // create a new compilation task 64 var task = compiler.getTask(null, fileMgr, null, null, null, compUnits); 65 66 // SourcePositions object to get positions of AST nodes 67 var sourcePositions = Trees.instance(task).sourcePositions; 68 69 // subclass SimpleTreeVisitor - to print empty catch 70 var EmptyCatchFinder = Java.extend(TreeScanner); 71 72 function hasOnlyEmptyStats(stats) { 73 var itr = stats.iterator(); 74 while (itr.hasNext()) { 75 if (! (itr.next() instanceof EmptyStatementTree)) { 76 return false; 77 } 78 } 79 80 return true; 81 } 82 83 var visitor = new EmptyCatchFinder() { 84 // current CompilationUnitTree 85 compUnit: null, 86 // current LineMap (pos -> line, column) 87 lineMap: null, 88 // current compilation unit's file name 89 fileName: null, 90 91 // overrides of TreeScanner methods 92 93 visitCompilationUnit: function(node, p) { 94 // capture info about current Compilation unit 95 this.compUnit = node; 96 this.lineMap = node.lineMap; 97 this.fileName = node.sourceFile.name; 98 99 // Using Java.super API to call super class method here 100 return Java.super(visitor).visitCompilationUnit(node, p); 101 }, 102 103 visitCatch: function (node, p) { 104 var stats = node.block.statements; 105 if (stats.empty || hasOnlyEmptyStats(stats)) { 106 // print information on this empty catch 107 var pos = sourcePositions.getStartPosition(this.compUnit, node); 108 var line = this.lineMap.getLineNumber(pos); 109 var col = this.lineMap.getColumnNumber(pos); 110 print("Exception swallow" + " @ " + this.fileName + ":" + line + ":" + col); 111 // print(node); 112 } 113 } 114 } 115 116 for each (var cu in task.parse()) { 117 cu.accept(visitor, null); 118 } 119 } 120 121 // for each ".java" file in directory (recursively) and check it! 122 function main(dir) { 123 Files.walk(dir.toPath()). 124 forEach(function(p) { 125 var name = p.toFile().absolutePath; 126 if (name.endsWith(".java")) { 127 try { 128 printEmptyCatch(p.toFile().getAbsolutePath()); 129 } catch (e) { 130 print(e); 131 } 132 } 133 }); 134 } 135 136 main(new File(arguments[0]));