code: /**
   * This file is part of Eclipse Steady.
   *
   * Licensed 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.
   *
   * SPDX-License-Identifier: Apache-2.0
   * SPDX-FileCopyrightText: Copyright (c) 2018-2020 SAP SE or an SAP affiliate company and Eclipse Steady contributors
   */
  package org.eclipse.steady.java.sign;
  
  import java.io.File;
  import java.io.IOException;
  import java.util.List;
  
  import org.apache.logging.log4j.Logger;
  import org.eclipse.jdt.internal.compiler.CompilationResult;
  import org.eclipse.jdt.internal.compiler.DefaultErrorHandlingPolicies;
  import org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration;
  import org.eclipse.jdt.internal.compiler.ast.CompilationUnitDeclaration;
  import org.eclipse.jdt.internal.compiler.ast.FieldDeclaration;
  import org.eclipse.jdt.internal.compiler.ast.TypeDeclaration;
  import org.eclipse.jdt.internal.compiler.batch.CompilationUnit;
  import org.eclipse.jdt.internal.compiler.classfmt.ClassFileConstants;
  import org.eclipse.jdt.internal.compiler.env.ICompilationUnit;
  import org.eclipse.jdt.internal.compiler.impl.CompilerOptions;
  import org.eclipse.jdt.internal.compiler.parser.Parser;
  import org.eclipse.jdt.internal.compiler.problem.DefaultProblemFactory;
  import org.eclipse.jdt.internal.compiler.problem.ProblemReporter;
  import org.eclipse.jdt.internal.core.util.CommentRecorderParser;
  import org.eclipse.steady.shared.util.FileUtil;
  
  import ch.uzh.ifi.seal.changedistiller.ast.java.Comment;
  import ch.uzh.ifi.seal.changedistiller.ast.java.CommentCollector;
  import ch.uzh.ifi.seal.changedistiller.ast.java.JavaCompilation;
  
  /**
   * Helper class to create the ASTSignature instances using ChangeDistiller.
   */
  public final class CompilationUtils {
  
    private static final Logger log =
        org.apache.logging.log4j.LogManager.getLogger(CompilationUtils.class);
  
    private CompilationUtils() {}
  
    /**
     * <p>compileSource.</p>
     *
     * @param source a {@link java.lang.String} object.
     * @return a {@link ch.uzh.ifi.seal.changedistiller.ast.java.JavaCompilation} object.
     */
    public static JavaCompilation compileSource(String source) {
  
      // Compiler Options
      CompilerOptions options = getDefaultCompilerOptions();
  
      // CommentRecorder
      Parser parser = createCommentRecorderParser(options);
  
      // Create Compilation Unit from Source
      ICompilationUnit cu = createCompilationunit(source, "");
  
      // Compilation Result
      CompilationResult compilationResult = createDefaultCompilationResult(cu, options);
  
      return new JavaCompilation(parser.parse(cu, compilationResult), parser.scanner);
    }
  
    private static CompilerOptions getDefaultCompilerOptions() {
      CompilerOptions options = new CompilerOptions();
      options.docCommentSupport = true;
      options.complianceLevel = ClassFileConstants.JDK1_7;
      options.sourceLevel = ClassFileConstants.JDK1_7;
      options.targetJDK = ClassFileConstants.JDK1_7;
      return options;
    }
  
    private static ICompilationUnit createCompilationunit(String _source_code, String filename) {
      char[] source_code = _source_code.toCharArray();
      ICompilationUnit cu = new CompilationUnit(source_code, filename, null);
      return cu;
    }
  
    /**
     * Returns the generated {@link JavaCompilation} from the file identified by the given filename.
     *
     * @param _filename
     *            of the file to compile
     * @return the compilation of the file
     */
    public static JavaCompilation compileFile(String _filename) {
      JavaCompilation jc = null;
      try {
        final String src = FileUtil.readFile(_filename);
        final CompilerOptions options = getDefaultCompilerOptions();
        final Parser parser = createCommentRecorderParser(options);
        final ICompilationUnit cu = createCompilationunit(src, _filename);
        final CompilationResult compilationResult = createDefaultCompilationResult(cu, options);
        jc = new JavaCompilation(parser.parse(cu, compilationResult), parser.scanner);
      } catch (IOException e) {
        log.error(e);
      }
      return jc;
    }
  
    /**
     *  Create a CommentRecorderParser
     * @param options - compiler options
     * @return
     */
    private static Parser createCommentRecorderParser(CompilerOptions options) {
      Parser parser =
          new CommentRecorderParser(
              new ProblemReporter(
                  DefaultErrorHandlingPolicies.proceedWithAllProblems(),
                  options,
                  new DefaultProblemFactory()),
              false);
      return parser;
    }
  
    private static CompilationResult createDefaultCompilationResult(
        ICompilationUnit cu, CompilerOptions options) {
      CompilationResult compilationResult =
          new CompilationResult(cu, 0, 0, options.maxProblemsPerUnit);
      return compilationResult;
    }
  
    /**
     * <p>extractComments.</p>
     *
     * @param sCompilationUnit a {@link ch.uzh.ifi.seal.changedistiller.ast.java.JavaCompilation} object.
     * @return a {@link java.util.List} object.
     */
    public static List<Comment> extractComments(JavaCompilation sCompilationUnit) {
      CommentCollector collector =
          new CommentCollector(sCompilationUnit.getCompilationUnit(), sCompilationUnit.getSource());
      collector.collect();
      return collector.getComments();
    }
  
    /**
     * <p>findMethod.</p>
     *
     * @param cu a {@link org.eclipse.jdt.internal.compiler.ast.CompilationUnitDeclaration} object.
     * @param methodName a {@link java.lang.String} object.
     * @return a {@link org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration} object.
     */
    public static AbstractMethodDeclaration findMethod(
        CompilationUnitDeclaration cu, String methodName) {
      for (TypeDeclaration type : cu.types) {
        for (AbstractMethodDeclaration method : type.methods) {
          if (String.valueOf(method.selector).equals(methodName)) {
            return method;
          }
        }
      }
      return null;
    }
  
    /**
     * <p>findField.</p>
     *
     * @param cu a {@link org.eclipse.jdt.internal.compiler.ast.CompilationUnitDeclaration} object.
     * @param fieldName a {@link java.lang.String} object.
     * @return a {@link org.eclipse.jdt.internal.compiler.ast.FieldDeclaration} object.
     */
    public static FieldDeclaration findField(CompilationUnitDeclaration cu, String fieldName) {
      for (TypeDeclaration type : cu.types) {
        for (FieldDeclaration field : type.fields) {
          if (String.valueOf(field.name).equals(fieldName)) {
            return field;
          }
        }
      }
      return null;
    }
  
    /**
     * <p>findType.</p>
     *
     * @param cu a {@link org.eclipse.jdt.internal.compiler.ast.CompilationUnitDeclaration} object.
     * @param typeName a {@link java.lang.String} object.
     * @return a {@link org.eclipse.jdt.internal.compiler.ast.TypeDeclaration} object.
     */
    public static TypeDeclaration findType(CompilationUnitDeclaration cu, String typeName) {
      for (TypeDeclaration type : cu.types) {
        for (TypeDeclaration memberType : type.memberTypes) {
          if (String.valueOf(memberType.name).equals(typeName)) {
            return memberType;
          }
        }
      }
      return null;
    }
  
    /**
     * <p>getFile.</p>
     *
     * @param filename a {@link java.lang.String} object.
     * @return a {@link java.io.File} object.
     */
    public static File getFile(String filename) {
      return new File(filename);
    }
  }
  