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Tomcat example source code file (JDTCompiler.java)

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

Java - Tomcat tags/keywords

compilation, compilationunit, compilationunit, fileoutputstream, icompilationunit, io, ioexception, ioexception, iproblem, javacerrordetail, nameenvironmentanswer, nameenvironmentanswer, string, string, util, vm

The Tomcat JDTCompiler.java source code

/*
 * 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.jasper.compiler;

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import java.util.StringTokenizer;

import org.apache.jasper.JasperException;
import org.eclipse.jdt.core.compiler.IProblem;
import org.eclipse.jdt.internal.compiler.ClassFile;
import org.eclipse.jdt.internal.compiler.CompilationResult;
import org.eclipse.jdt.internal.compiler.Compiler;
import org.eclipse.jdt.internal.compiler.DefaultErrorHandlingPolicies;
import org.eclipse.jdt.internal.compiler.ICompilerRequestor;
import org.eclipse.jdt.internal.compiler.IErrorHandlingPolicy;
import org.eclipse.jdt.internal.compiler.IProblemFactory;
import org.eclipse.jdt.internal.compiler.classfmt.ClassFileReader;
import org.eclipse.jdt.internal.compiler.env.ICompilationUnit;
import org.eclipse.jdt.internal.compiler.env.INameEnvironment;
import org.eclipse.jdt.internal.compiler.env.NameEnvironmentAnswer;
import org.eclipse.jdt.internal.compiler.impl.CompilerOptions;
import org.eclipse.jdt.internal.compiler.problem.DefaultProblemFactory;

/**
 * JDT class compiler. This compiler will load source dependencies from the
 * context classloader, reducing dramatically disk access during 
 * the compilation process.
 *
 * @author Cocoon2
 * @author Remy Maucherat
 */
public class JDTCompiler extends org.apache.jasper.compiler.Compiler {

    
    /** 
     * Compile the servlet from .java file to .class file
     */
    protected void generateClass(String[] smap)
        throws FileNotFoundException, JasperException, Exception {

        long t1 = 0;
        if (log.isDebugEnabled()) {
            t1 = System.currentTimeMillis();
        }
        
        final String sourceFile = ctxt.getServletJavaFileName();
        final String outputDir = ctxt.getOptions().getScratchDir().getAbsolutePath();
        String packageName = ctxt.getServletPackageName();
        final String targetClassName = 
            ((packageName.length() != 0) ? (packageName + ".") : "") 
                    + ctxt.getServletClassName();
        final ClassLoader classLoader = ctxt.getJspLoader();
        String[] fileNames = new String[] {sourceFile};
        String[] classNames = new String[] {targetClassName};
        final ArrayList problemList = new ArrayList();
        
        class CompilationUnit implements ICompilationUnit {

            String className;
            String sourceFile;

            CompilationUnit(String sourceFile, String className) {
                this.className = className;
                this.sourceFile = sourceFile;
            }

            public char[] getFileName() {
                return sourceFile.toCharArray();
            }
            
            public char[] getContents() {
                char[] result = null;
                FileInputStream is = null;
                try {
                    is = new FileInputStream(sourceFile);
                    Reader reader = 
                        new BufferedReader(new InputStreamReader(is, ctxt.getOptions().getJavaEncoding()));
                    if (reader != null) {
                        char[] chars = new char[8192];
                        StringBuffer buf = new StringBuffer();
                        int count;
                        while ((count = reader.read(chars, 0, 
                                                    chars.length)) > 0) {
                            buf.append(chars, 0, count);
                        }
                        result = new char[buf.length()];
                        buf.getChars(0, result.length, result, 0);
                    }
                } catch (IOException e) {
                    log.error("Compilation error", e);
                } finally {
                    if (is != null) {
                        try {
                            is.close();
                        } catch (IOException exc) {
                            // Ignore
                        }
                    }
                }
                return result;
            }
            
            public char[] getMainTypeName() {
                int dot = className.lastIndexOf('.');
                if (dot > 0) {
                    return className.substring(dot + 1).toCharArray();
                }
                return className.toCharArray();
            }
            
            public char[][] getPackageName() {
                StringTokenizer izer = 
                    new StringTokenizer(className, ".");
                char[][] result = new char[izer.countTokens()-1][];
                for (int i = 0; i < result.length; i++) {
                    String tok = izer.nextToken();
                    result[i] = tok.toCharArray();
                }
                return result;
            }
        }

        final INameEnvironment env = new INameEnvironment() {

                public NameEnvironmentAnswer 
                    findType(char[][] compoundTypeName) {
                    String result = "";
                    String sep = "";
                    for (int i = 0; i < compoundTypeName.length; i++) {
                        result += sep;
                        result += new String(compoundTypeName[i]);
                        sep = ".";
                    }
                    return findType(result);
                }

                public NameEnvironmentAnswer 
                    findType(char[] typeName, 
                             char[][] packageName) {
                        String result = "";
                        String sep = "";
                        for (int i = 0; i < packageName.length; i++) {
                            result += sep;
                            result += new String(packageName[i]);
                            sep = ".";
                        }
                        result += sep;
                        result += new String(typeName);
                        return findType(result);
                }
                
                private NameEnvironmentAnswer findType(String className) {

                    InputStream is = null;
                    try {
                        if (className.equals(targetClassName)) {
                            ICompilationUnit compilationUnit = 
                                new CompilationUnit(sourceFile, className);
                            return 
                                new NameEnvironmentAnswer(compilationUnit, null);
                        }
                        String resourceName = 
                            className.replace('.', '/') + ".class";
                        is = classLoader.getResourceAsStream(resourceName);
                        if (is != null) {
                            byte[] classBytes;
                            byte[] buf = new byte[8192];
                            ByteArrayOutputStream baos = 
                                new ByteArrayOutputStream(buf.length);
                            int count;
                            while ((count = is.read(buf, 0, buf.length)) > 0) {
                                baos.write(buf, 0, count);
                            }
                            baos.flush();
                            classBytes = baos.toByteArray();
                            char[] fileName = className.toCharArray();
                            ClassFileReader classFileReader = 
                                new ClassFileReader(classBytes, fileName, 
                                                    true);
                            return 
                                new NameEnvironmentAnswer(classFileReader, null);
                        }
                    } catch (IOException exc) {
                        log.error("Compilation error", exc);
                    } catch (org.eclipse.jdt.internal.compiler.classfmt.ClassFormatException exc) {
                        log.error("Compilation error", exc);
                    } finally {
                        if (is != null) {
                            try {
                                is.close();
                            } catch (IOException exc) {
                                // Ignore
                            }
                        }
                    }
                    return null;
                }

                private boolean isPackage(String result) {
                    if (result.equals(targetClassName)) {
                        return false;
                    }
                    String resourceName = result.replace('.', '/') + ".class";
                    InputStream is = 
                        classLoader.getResourceAsStream(resourceName);
                    return is == null;
                }

                public boolean isPackage(char[][] parentPackageName, 
                                         char[] packageName) {
                    String result = "";
                    String sep = "";
                    if (parentPackageName != null) {
                        for (int i = 0; i < parentPackageName.length; i++) {
                            result += sep;
                            String str = new String(parentPackageName[i]);
                            result += str;
                            sep = ".";
                        }
                    }
                    String str = new String(packageName);
                    if (Character.isUpperCase(str.charAt(0))) {
                        if (!isPackage(result)) {
                            return false;
                        }
                    }
                    result += sep;
                    result += str;
                    return isPackage(result);
                }

                public void cleanup() {
                }

            };

        final IErrorHandlingPolicy policy = 
            DefaultErrorHandlingPolicies.proceedWithAllProblems();

        final Map settings = new HashMap();
        settings.put(CompilerOptions.OPTION_LineNumberAttribute,
                     CompilerOptions.GENERATE);
        settings.put(CompilerOptions.OPTION_SourceFileAttribute,
                     CompilerOptions.GENERATE);
        settings.put(CompilerOptions.OPTION_ReportDeprecation,
                     CompilerOptions.IGNORE);
        if (ctxt.getOptions().getJavaEncoding() != null) {
            settings.put(CompilerOptions.OPTION_Encoding,
                    ctxt.getOptions().getJavaEncoding());
        }
        if (ctxt.getOptions().getClassDebugInfo()) {
            settings.put(CompilerOptions.OPTION_LocalVariableAttribute,
                         CompilerOptions.GENERATE);
        }

        // Source JVM
        if(ctxt.getOptions().getCompilerSourceVM() != null) {
            String opt = ctxt.getOptions().getCompilerSourceVM();
            if(opt.equals("1.1")) {
                settings.put(CompilerOptions.OPTION_Source,
                             CompilerOptions.VERSION_1_1);
            } else if(opt.equals("1.2")) {
                settings.put(CompilerOptions.OPTION_Source,
                             CompilerOptions.VERSION_1_2);
            } else if(opt.equals("1.3")) { 
                settings.put(CompilerOptions.OPTION_Source,
                             CompilerOptions.VERSION_1_3);
            } else if(opt.equals("1.4")) {
                settings.put(CompilerOptions.OPTION_Source,
                             CompilerOptions.VERSION_1_4);
            } else if(opt.equals("1.5")) {
                settings.put(CompilerOptions.OPTION_Source,
                             CompilerOptions.VERSION_1_5);
            } else {
                log.warn("Unknown source VM " + opt + " ignored.");
                settings.put(CompilerOptions.OPTION_Source,
                        CompilerOptions.VERSION_1_5);
            }
        } else {
            // Default to 1.5
            settings.put(CompilerOptions.OPTION_Source,
                    CompilerOptions.VERSION_1_5);
        }
        
        // Target JVM
        if(ctxt.getOptions().getCompilerTargetVM() != null) {
            String opt = ctxt.getOptions().getCompilerTargetVM();
            if(opt.equals("1.1")) {
                settings.put(CompilerOptions.OPTION_TargetPlatform,
                             CompilerOptions.VERSION_1_1);
            } else if(opt.equals("1.2")) {
                settings.put(CompilerOptions.OPTION_TargetPlatform,
                             CompilerOptions.VERSION_1_2);
            } else if(opt.equals("1.3")) { 
                settings.put(CompilerOptions.OPTION_TargetPlatform,
                             CompilerOptions.VERSION_1_3);
            } else if(opt.equals("1.4")) {
                settings.put(CompilerOptions.OPTION_TargetPlatform,
                             CompilerOptions.VERSION_1_4);
            } else if(opt.equals("1.5")) {
                settings.put(CompilerOptions.OPTION_TargetPlatform,
                             CompilerOptions.VERSION_1_5);
                settings.put(CompilerOptions.OPTION_Compliance,
                        CompilerOptions.VERSION_1_5);
            } else {
                log.warn("Unknown target VM " + opt + " ignored.");
                settings.put(CompilerOptions.OPTION_TargetPlatform,
                        CompilerOptions.VERSION_1_5);
            }
        } else {
            // Default to 1.5
            settings.put(CompilerOptions.OPTION_TargetPlatform,
                    CompilerOptions.VERSION_1_5);
            settings.put(CompilerOptions.OPTION_Compliance,
                    CompilerOptions.VERSION_1_5);
        }

        final IProblemFactory problemFactory = 
            new DefaultProblemFactory(Locale.getDefault());
        
        final ICompilerRequestor requestor = new ICompilerRequestor() {
                public void acceptResult(CompilationResult result) {
                    try {
                        if (result.hasProblems()) {
                            IProblem[] problems = result.getProblems();
                            for (int i = 0; i < problems.length; i++) {
                                IProblem problem = problems[i];
                                if (problem.isError()) {
                                    String name = 
                                        new String(problems[i].getOriginatingFileName());
                                    try {
                                        problemList.add(ErrorDispatcher.createJavacError
                                                (name, pageNodes, new StringBuffer(problem.getMessage()), 
                                                        problem.getSourceLineNumber(), ctxt));
                                    } catch (JasperException e) {
                                        log.error("Error visiting node", e);
                                    }
                                }
                            }
                        }
                        if (problemList.isEmpty()) {
                            ClassFile[] classFiles = result.getClassFiles();
                            for (int i = 0; i < classFiles.length; i++) {
                                ClassFile classFile = classFiles[i];
                                char[][] compoundName = 
                                    classFile.getCompoundName();
                                String className = "";
                                String sep = "";
                                for (int j = 0; 
                                     j < compoundName.length; j++) {
                                    className += sep;
                                    className += new String(compoundName[j]);
                                    sep = ".";
                                }
                                byte[] bytes = classFile.getBytes();
                                String outFile = outputDir + "/" + 
                                    className.replace('.', '/') + ".class";
                                FileOutputStream fout = 
                                    new FileOutputStream(outFile);
                                BufferedOutputStream bos = 
                                    new BufferedOutputStream(fout);
                                bos.write(bytes);
                                bos.close();
                            }
                        }
                    } catch (IOException exc) {
                        log.error("Compilation error", exc);
                    }
                }
            };

        ICompilationUnit[] compilationUnits = 
            new ICompilationUnit[classNames.length];
        for (int i = 0; i < compilationUnits.length; i++) {
            String className = classNames[i];
            compilationUnits[i] = new CompilationUnit(fileNames[i], className);
        }
        Compiler compiler = new Compiler(env,
                                         policy,
                                         settings,
                                         requestor,
                                         problemFactory,
                                         true);
        compiler.compile(compilationUnits);

        if (!ctxt.keepGenerated()) {
            File javaFile = new File(ctxt.getServletJavaFileName());
            javaFile.delete();
        }
    
        if (!problemList.isEmpty()) {
            JavacErrorDetail[] jeds = 
                (JavacErrorDetail[]) problemList.toArray(new JavacErrorDetail[0]);
            errDispatcher.javacError(jeds);
        }
        
        if( log.isDebugEnabled() ) {
            long t2=System.currentTimeMillis();
            log.debug("Compiled " + ctxt.getServletJavaFileName() + " "
                      + (t2-t1) + "ms");
        }

        if (ctxt.isPrototypeMode()) {
            return;
        }

        // JSR45 Support
        if (! options.isSmapSuppressed()) {
            SmapUtil.installSmap(smap);
        }
        
    }
    
    
}

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