sundar@1531: #// Usage: jjs exceptionswallow.js -- <directory>
sundar@1531: 
sundar@1531: /*
sundar@1531:  * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
sundar@1531:  *
sundar@1531:  * Redistribution and use in source and binary forms, with or without
sundar@1531:  * modification, are permitted provided that the following conditions
sundar@1531:  * are met:
sundar@1531:  *
sundar@1531:  *   - Redistributions of source code must retain the above copyright
sundar@1531:  *     notice, this list of conditions and the following disclaimer.
sundar@1531:  *
sundar@1531:  *   - Redistributions in binary form must reproduce the above copyright
sundar@1531:  *     notice, this list of conditions and the following disclaimer in the
sundar@1531:  *     documentation and/or other materials provided with the distribution.
sundar@1531:  *
sundar@1531:  *   - Neither the name of Oracle nor the names of its
sundar@1531:  *     contributors may be used to endorse or promote products derived
sundar@1531:  *     from this software without specific prior written permission.
sundar@1531:  *
sundar@1531:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
sundar@1531:  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
sundar@1531:  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
sundar@1531:  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
sundar@1531:  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
sundar@1531:  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
sundar@1531:  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
sundar@1531:  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
sundar@1531:  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
sundar@1531:  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
sundar@1531:  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
sundar@1531:  */
sundar@1531: 
sundar@1531: // This example demonstrates Java subclassing by Java.extend
sundar@1531: // and javac Compiler and Tree API. This example looks for
sundar@1531: // empty catch blocks ("exception swallow") and reports those.
sundar@1531: 
sundar@1531: if (arguments.length == 0) {
sundar@1531:     print("Usage: jjs exceptionswallow.js -- <directory>");
sundar@1531:     exit(1);
sundar@1531: }
sundar@1531:  
sundar@1531: // Java types used
sundar@1531: var File = Java.type("java.io.File");
sundar@1531: var Files = Java.type("java.nio.file.Files");
sundar@1531: var StringArray = Java.type("java.lang.String[]");
sundar@1531: var ToolProvider = Java.type("javax.tools.ToolProvider");
sundar@1531: var Tree = Java.type("com.sun.source.tree.Tree");
sundar@1531: var EmptyStatementTree = Java.type("com.sun.source.tree.EmptyStatementTree");
sundar@1531: var Trees = Java.type("com.sun.source.util.Trees");
sundar@1531: var TreeScanner = Java.type("com.sun.source.util.TreeScanner");
sundar@1531: 
sundar@1531: // printEmptyCatch
sundar@1531: 
sundar@1531: function printEmptyCatch() {
sundar@1531:     // get the system compiler tool
sundar@1531:     var compiler = ToolProvider.systemJavaCompiler;
sundar@1531:     // get standard file manager
sundar@1531:     var fileMgr = compiler.getStandardFileManager(null, null, null);
sundar@1531:     // Using Java.to convert script array (arguments) to a Java String[]
sundar@1531:     var compUnits = fileMgr.getJavaFileObjects(
sundar@1531:         Java.to(arguments, StringArray));
sundar@1531:     // create a new compilation task
sundar@1531:     var task = compiler.getTask(null, fileMgr, null, null, null, compUnits);
sundar@1531: 
sundar@1531:     // SourcePositions object to get positions of AST nodes
sundar@1531:     var sourcePositions = Trees.instance(task).sourcePositions;
sundar@1531: 
sundar@1531:     // subclass SimpleTreeVisitor - to print empty catch
sundar@1531:     var EmptyCatchFinder = Java.extend(TreeScanner);
sundar@1531:    
sundar@1531:     function hasOnlyEmptyStats(stats) {
sundar@1531:         var itr = stats.iterator();
sundar@1531:         while (itr.hasNext()) {
sundar@1531:             if (! (itr.next() instanceof EmptyStatementTree)) {
sundar@1531:                 return false;
sundar@1531:             }
sundar@1531:         }
sundar@1531: 
sundar@1531:         return true;
sundar@1531:     }
sundar@1531:  
sundar@1531:     var visitor = new EmptyCatchFinder() {
sundar@1531:         // current CompilationUnitTree
sundar@1531:         compUnit: null,
sundar@1531:         // current LineMap (pos -> line, column)
sundar@1531:         lineMap: null,
sundar@1531:         // current compilation unit's file name
sundar@1531:         fileName: null,
sundar@1531: 
sundar@1531:         // overrides of TreeScanner methods
sundar@1531: 
sundar@1531:         visitCompilationUnit: function(node, p) {
sundar@1531:             // capture info about current Compilation unit
sundar@1531:             this.compUnit = node;
sundar@1531:             this.lineMap = node.lineMap;
sundar@1531:             this.fileName = node.sourceFile.name;
sundar@1531: 
sundar@1531:             // Using Java.super API to call super class method here
sundar@1531:             return Java.super(visitor).visitCompilationUnit(node, p);
sundar@1531:         },
sundar@1531: 
sundar@1531:         visitCatch: function (node, p) {
sundar@1531:             var stats = node.block.statements;
sundar@1531:             if (stats.empty || hasOnlyEmptyStats(stats)) {
sundar@1531:                 // print information on this empty catch
sundar@1531:                 var pos = sourcePositions.getStartPosition(this.compUnit, node);
sundar@1531:                 var line = this.lineMap.getLineNumber(pos);
sundar@1531:                 var col = this.lineMap.getColumnNumber(pos);
sundar@1531:                 print("Exception swallow" + " @ " + this.fileName + ":" + line + ":" + col);
sundar@1531:                 // print(node);
sundar@1531:             }
sundar@1531:         }
sundar@1531:     }
sundar@1531:  
sundar@1531:     for each (var cu in task.parse()) {
sundar@1531:         cu.accept(visitor, null);
sundar@1531:     }
sundar@1531: }
sundar@1531:  
sundar@1531: // for each ".java" file in directory (recursively) and check it!
sundar@1531: function main(dir) {
sundar@1531:     Files.walk(dir.toPath()).
sundar@1531:       forEach(function(p) {
sundar@1531:         var name = p.toFile().absolutePath;
sundar@1531:         if (name.endsWith(".java")) {
sundar@1531:             try {
sundar@1531:                 printEmptyCatch(p.toFile().getAbsolutePath());
sundar@1531:             } catch (e) {
sundar@1531:                 print(e);
sundar@1531:             }
sundar@1531:         }
sundar@1531:       });
sundar@1531: }
sundar@1531:  
sundar@1531: main(new File(arguments[0]));