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Java example source code file (jvmtiEnvFill.java)

This example Java source code file (jvmtiEnvFill.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

arraylist, filereader, filewriter, function, hashmap, ioexception, iterator, jvmtienv, linenumberreader, printwriter, sourcefile, string, util

The jvmtiEnvFill.java Java example source code

/*
 * Copyright (c) 2003, 2005, 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.
 *
 */

import java.io.*;
import java.util.*;

class jvmtiEnvFill {

    public static void main(String[] args) throws IOException {
        if (args.length != 3) {
            System.err.println("usage: <filledFile>  ");
            System.exit(1);
        }
        String filledFN = args[0];
        String stubFN = args[1];
        String resultFN = args[2];

        SourceFile filledSF = new SourceFile(filledFN);
        SourceFile stubSF = new SourceFile(stubFN);


        stubSF.fill(filledSF);

        PrintWriter out = new PrintWriter(new FileWriter(resultFN));
        stubSF.output(out);
        out.close();
    }
}

class SourceFile {

    static final String endFilePrefix = "// end file prefix";
    static final String functionPrefix = "JvmtiEnv::";

    final String fn;
    LineNumberReader in;
    String line;
    List<String> top = new ArrayList();
    List<String> before = new ArrayList();
    boolean inFilePrefix = true;
    List<Function> functions = new ArrayList();
    Map<String, Function> functionMap = new HashMap();

    class Function {
      String name;
      String args;
      String compareArgs;
      List comment;
      List<String> body = new ArrayList();

      Function() throws IOException {
        line = in.readLine();
        String trimmed = line.trim();
        if (!trimmed.startsWith(functionPrefix)) {
            error("expected '" + functionPrefix + "'");
        }
        int index = trimmed.indexOf('(', functionPrefix.length());
        if (index == -1) {
            error("missing open paren");
        }
        name = trimmed.substring(functionPrefix.length(), index);
        int index2 = trimmed.indexOf(')', index);
        if (index2 == -1) {
            error("missing close paren - must be on same line");
        }
        args = trimmed.substring(index+1, index2);
        compareArgs = args.replaceAll("\\s", "");
        String tail = trimmed.substring(index2+1).trim();
        if (!tail.equals("{")) {
            error("function declaration first line must end with open bracket '{', instead got '" +
                   tail + "'");
        }
        while(true) {
            line = in.readLine();
            if (line == null) {
                line = ""; // so error does not look wierd
                error("unexpected end of file");
            }
            if (line.startsWith("}")) {
                break;
            }
            body.add(line);
        }
        String expected = "} /* end " + name + " */";
        trimmed = line.replaceAll("\\s","");
        if (!trimmed.equals(expected.replaceAll("\\s",""))) {
            error("function end is malformed - should be: " + expected);
        }
        // copy over the comment prefix
        comment = before;
        before = new ArrayList<String>();
      }

      void remove() {
        functionMap.remove(name);
      }

      String fileName() {
        return fn;
      }

      void fill(Function filledFunc) {
        if (filledFunc == null) {
            System.err.println("Warning: function " + name + " missing from filled file");
            body.add(0, "    /*** warning: function added and not filled in ***/");
        } else {
            int fbsize = filledFunc.body.size();
            int bsize = body.size();
            if (fbsize > bsize  || !body.subList(bsize-fbsize,bsize).equals(filledFunc.body)) {
                // it has actually been filled in
                body = filledFunc.body;
                if (!compareArgs.equals(filledFunc.compareArgs)) {
                    System.err.println("Warning: function " + name +
                                       ": filled and stub arguments differ");
                    System.err.println("  old (filled): " + filledFunc.args);
                    System.err.println("  new (stub): " + args);
                    body.add(0, "    /*** warning: arguments changed, were: " +
                             filledFunc.args + " ***/");
                }
            }
            filledFunc.remove();  // mark used
        }
      }

      void output(PrintWriter out) {
            Iterator it = comment.iterator();
            while (it.hasNext()) {
                out.println(it.next());
            }
            out.println("jvmtiError");
            out.print(functionPrefix);
            out.print(name);
            out.print('(');
            out.print(args);
            out.println(") {");
            it = body.iterator();
            while (it.hasNext()) {
                out.println(it.next());
            }
            out.print("} /* end ");
            out.print(name);
            out.println(" */");
      }
    }

    SourceFile(String fn) throws IOException {
        this.fn = fn;
        Reader reader = new FileReader(fn);
        in = new LineNumberReader(reader);

        while (readGaps()) {
            Function func = new Function();
            functionMap.put(func.name, func);
            functions.add(func);
        }

        in.close();
    }

    void error(String msg) {
        System.err.println("Fatal error parsing file: " + fn);
        System.err.println("Line number: " + in.getLineNumber());
        System.err.println("Error message: " + msg);
        System.err.println("Source line: " + line);
        System.exit(1);
    }

    boolean readGaps() throws IOException {
        while(true) {
            line = in.readLine();
            if (line == null) {
                return false; // end of file
            }
            if (!inFilePrefix && line.startsWith("}")) {
                error("unexpected close bracket in first column, outside of function.\n");
            }
            String trimmed = line.trim();
            if (line.startsWith("jvmtiError")) {
                if (trimmed.equals("jvmtiError")) {
                    if (inFilePrefix) {
                        error("unexpected 'jvmtiError' line in file prefix.\n" +
                              "is '" + endFilePrefix + "'... line missing?");
                    }
                    return true; // beginning of a function
                } else {
                    error("extra characters at end of 'jvmtiError'");
                }
            }
            if (inFilePrefix) {
                top.add(line);
            } else {
                trimmed = line.trim();
                if (!trimmed.equals("") && !trimmed.startsWith("//") && !trimmed.startsWith("#")) {
                    error("only comments and blank lines allowed between functions");
                }
                before.add(line);
            }
            if (line.replaceAll("\\s","").toLowerCase().startsWith(endFilePrefix.replaceAll("\\s",""))) {
                if (!inFilePrefix) {
                    error("excess '" + endFilePrefix + "'");
                }
                inFilePrefix = false;
            }
        }
    }

    void fill(SourceFile filledSF) {
        // copy beginning of file straight from filled file
        top = filledSF.top;

        // file in functions
        Iterator it = functions.iterator();
        while (it.hasNext()) {
            Function stubFunc = (Function)(it.next());
            Function filledFunc = (Function)filledSF.functionMap.get(stubFunc.name);
            stubFunc.fill(filledFunc);
        }
        if (filledSF.functionMap.size() > 0) {
            System.err.println("Warning: the following functions were present in the " +
                                "filled file but missing in the stub file and thus not copied:");
            it  = filledSF.functionMap.values().iterator();
            while (it.hasNext()) {
                System.err.println("        " + ((Function)(it.next())).name);
            }
        }
    }

    void output(PrintWriter out) {
        Iterator it = top.iterator();
        while (it.hasNext()) {
            out.println(it.next());
        }
        it = functions.iterator();
        while (it.hasNext()) {
            Function stubFunc = (Function)(it.next());
            stubFunc.output(out);
        }
    }
}

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