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