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	/*
	* Copyright (C) 2007-2010 Júlio Vilmar Gesser.
	* Copyright (C) 2011, 2013-2021 The JavaParser Team.
	*
	* This file is part of JavaParser.
	*
	* JavaParser can be used either under the terms of
	* a) the GNU Lesser General Public License as published by
	* the Free Software Foundation, either version 3 of the License, or
	* (at your option) any later version.
	* b) the terms of the Apache License
	*
	* You should have received a copy of both licenses in LICENCE.LGPL and
	* LICENCE.APACHE. Please refer to those files for details.
	*
	* JavaParser 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 Lesser General Public License for more details.
	*/

	package com.github.javaparser;

	import com.github.javaparser.ast.CompilationUnit;
	import com.github.javaparser.ast.ImportDeclaration;
	import com.github.javaparser.ast.Node;
	import com.github.javaparser.ast.PackageDeclaration;
	import com.github.javaparser.ast.body.BodyDeclaration;
	import com.github.javaparser.ast.body.MethodDeclaration;
	import com.github.javaparser.ast.body.Parameter;
	import com.github.javaparser.ast.body.TypeDeclaration;
	import com.github.javaparser.ast.expr.*;
	import com.github.javaparser.ast.modules.ModuleDeclaration;
	import com.github.javaparser.ast.modules.ModuleDirective;
	import com.github.javaparser.ast.stmt.BlockStmt;
	import com.github.javaparser.ast.stmt.ExplicitConstructorInvocationStmt;
	import com.github.javaparser.ast.stmt.Statement;
	import com.github.javaparser.ast.type.ClassOrInterfaceType;
	import com.github.javaparser.ast.type.Type;
	import com.github.javaparser.ast.type.TypeParameter;

	import java.io.*;
	import java.nio.charset.Charset;
	import java.nio.file.Path;

	import static com.github.javaparser.ParseStart.*;
	import static com.github.javaparser.Problem.PROBLEM_BY_BEGIN_POSITION;
	import static com.github.javaparser.Providers.*;
	import static com.github.javaparser.utils.Utils.assertNotNull;

	/**
	* Parse Java source code and creates Abstract Syntax Trees.
	*
	* @author Júlio Vilmar Gesser
	* @see StaticJavaParser
	*/
	public final class JavaParser {
	private final ParserConfiguration configuration;

	private GeneratedJavaParser astParser = null;

	/**
	* Instantiate the parser with default configuration. Note that parsing can also be done with the static methods {@link StaticJavaParser}.
	* Creating an instance will reduce setup time between parsing files.
	*/
	public JavaParser() {
	this(new ParserConfiguration());
	}

	/**
	* Instantiate the parser. Note that parsing can also be done with the static methods {@link StaticJavaParser}.
	* Creating an instance will reduce setup time between parsing files.
	*/
	public JavaParser(ParserConfiguration configuration) {
	this.configuration = configuration;
	}

	/**
	* @return The configuration for this parser.
	*/
	public ParserConfiguration getParserConfiguration() {
	return this.configuration;
	}

	private GeneratedJavaParser getParserForProvider(Provider provider) {
	if (astParser == null) {
	astParser = new GeneratedJavaParser(provider);
	} else {
	astParser.reset(provider);
	}
	astParser.setTabSize(configuration.getTabSize());
	astParser.setStoreTokens(configuration.isStoreTokens());

	ParserConfiguration.LanguageLevel languageLevel = configuration.getLanguageLevel();
	if (languageLevel != null) {
	if(languageLevel.isYieldSupported()) {
	astParser.setYieldSupported();
	}
	}
	return astParser;
	}

	/**
	* Parses source code.
	* It takes the source code from a Provider.
	* The start indicates what can be found in the source code (compilation unit, block, import...)
	*
	* @param start refer to the constants in ParseStart to see what can be parsed.
	* @param provider refer to Providers to see how you can read source. The provider will be closed after parsing.
	* @param <N> the subclass of Node that is the result of parsing in the start.
	* @return the parse result, a collection of encountered problems, and some extra data.
	*/
	public <N extends Node> ParseResult<N> parse(ParseStart<N> start, Provider provider) {
	assertNotNull(start);
	assertNotNull(provider);

	for (PreProcessor preProcessor : configuration.getPreProcessors()) {
	provider = preProcessor.process(provider);
	}

	final GeneratedJavaParser parser = getParserForProvider(provider);
	try {
	N resultNode = start.parse(parser);
	ParseResult<N> result = new ParseResult<>(resultNode, parser.problems, parser.getCommentsCollection());

	configuration.getPostProcessors()
	.forEach(postProcessor -> postProcessor.process(result, configuration));

	result.getProblems()
	.sort(PROBLEM_BY_BEGIN_POSITION);

	return result;
	} catch (Exception e) {
	final String message = e.getMessage() == null ? "Unknown error" : e.getMessage();
	parser.problems.add(new Problem(message, null, e));
	return new ParseResult<>(null, parser.problems, parser.getCommentsCollection());
	} finally {
	try {
	provider.close();
	} catch (IOException e) {
	// Since we're done parsing and have our result, we don't care about any errors.
	}
	}
	}

	/**
	* Parses the Java code contained in the {@link InputStream} and returns a
	* {@link CompilationUnit} that represents it.
	*
	* @param in {@link InputStream} containing Java source code. It will be closed after parsing.
	* @param encoding encoding of the source code
	* @return CompilationUnit representing the Java source code
	* @throws ParseProblemException if the source code has parser errors
	*/
	public ParseResult<CompilationUnit> parse(final InputStream in, Charset encoding) {
	return parse(COMPILATION_UNIT, provider(in, encoding));
	}

	/**
	* Parses the Java code contained in the {@link InputStream} and returns a
	* {@link CompilationUnit} that represents it.<br>
	*
	* @param in {@link InputStream} containing Java source code. It will be closed after parsing.
	* @return CompilationUnit representing the Java source code
	* @throws ParseProblemException if the source code has parser errors
	*/
	public ParseResult<CompilationUnit> parse(final InputStream in) {
	return parse(in, configuration.getCharacterEncoding());
	}

	/**
	* Parses the Java code contained in a {@link File} and returns a
	* {@link CompilationUnit} that represents it.
	*
	* @param file {@link File} containing Java source code. It will be closed after parsing.
	* @param encoding encoding of the source code
	* @return CompilationUnit representing the Java source code
	* @throws ParseProblemException if the source code has parser errors
	* @throws FileNotFoundException the file was not found
	* @deprecated set the encoding in the {@link ParserConfiguration}
	*/
	@Deprecated
	public ParseResult<CompilationUnit> parse(final File file, final Charset encoding) throws FileNotFoundException {
	ParseResult<CompilationUnit> result = parse(COMPILATION_UNIT, provider(file, encoding));
	result.getResult().ifPresent(cu -> cu.setStorage(file.toPath(), encoding));
	return result;
	}

	/**
	* Parses the Java code contained in a {@link File} and returns a
	* {@link CompilationUnit} that represents it.<br>
	*
	* @param file {@link File} containing Java source code. It will be closed after parsing.
	* @return CompilationUnit representing the Java source code
	* @throws ParseProblemException if the source code has parser errors
	* @throws FileNotFoundException the file was not found
	*/
	public ParseResult<CompilationUnit> parse(final File file) throws FileNotFoundException {
	ParseResult<CompilationUnit> result = parse(COMPILATION_UNIT, provider(file, configuration.getCharacterEncoding()));
	result.getResult().ifPresent(cu -> cu.setStorage(file.toPath(), configuration.getCharacterEncoding()));
	return result;
	}

	/**
	* Parses the Java code contained in a file and returns a
	* {@link CompilationUnit} that represents it.
	*
	* @param path path to a file containing Java source code
	* @param encoding encoding of the source code
	* @return CompilationUnit representing the Java source code
	* @throws IOException the path could not be accessed
	* @throws ParseProblemException if the source code has parser errors
	* @deprecated set the encoding in the {@link ParserConfiguration}
	*/
	@Deprecated
	public ParseResult<CompilationUnit> parse(final Path path, final Charset encoding) throws IOException {
	ParseResult<CompilationUnit> result = parse(COMPILATION_UNIT, provider(path, encoding));
	result.getResult().ifPresent(cu -> cu.setStorage(path, encoding));
	return result;
	}

	/**
	* Parses the Java code contained in a file and returns a
	* {@link CompilationUnit} that represents it.<br>
	*
	* @param path path to a file containing Java source code
	* @return CompilationUnit representing the Java source code
	* @throws ParseProblemException if the source code has parser errors
	* @throws IOException the path could not be accessed
	*/
	public ParseResult<CompilationUnit> parse(final Path path) throws IOException {
	ParseResult<CompilationUnit> result = parse(COMPILATION_UNIT, provider(path, configuration.getCharacterEncoding()));
	result.getResult().ifPresent(cu -> cu.setStorage(path, configuration.getCharacterEncoding()));
	return result;
	}

	/**
	* Parses the Java code contained in a resource and returns a
	* {@link CompilationUnit} that represents it.<br>
	*
	* @param path path to a resource containing Java source code. As resource is accessed through a class loader, a
	* leading "/" is not allowed in pathToResource
	* @return CompilationUnit representing the Java source code
	* @throws ParseProblemException if the source code has parser errors
	* @throws IOException the path could not be accessed
	*/
	public ParseResult<CompilationUnit> parseResource(final String path) throws IOException {
	return parse(COMPILATION_UNIT, resourceProvider(path, configuration.getCharacterEncoding()));
	}

	/**
	* Parses the Java code contained in a resource and returns a
	* {@link CompilationUnit} that represents it.<br>
	*
	* @param path path to a resource containing Java source code. As resource is accessed through a class loader, a
	* leading "/" is not allowed in pathToResource
	* @param encoding encoding of the source code
	* @return CompilationUnit representing the Java source code
	* @throws ParseProblemException if the source code has parser errors
	* @throws IOException the path could not be accessed
	* @deprecated set the encoding in the {@link ParserConfiguration}
	*/
	@Deprecated
	public ParseResult<CompilationUnit> parseResource(final String path, Charset encoding) throws IOException {
	return parse(COMPILATION_UNIT, resourceProvider(path, encoding));
	}

	/**
	* Parses the Java code contained in a resource and returns a
	* {@link CompilationUnit} that represents it.<br>
	*
	* @param classLoader the classLoader that is asked to load the resource
	* @param path path to a resource containing Java source code. As resource is accessed through a class loader, a
	* leading "/" is not allowed in pathToResource
	* @return CompilationUnit representing the Java source code
	* @throws ParseProblemException if the source code has parser errors
	* @throws IOException the path could not be accessed
	* @deprecated set the encoding in the {@link ParserConfiguration}
	*/
	@Deprecated
	public ParseResult<CompilationUnit> parseResource(final ClassLoader classLoader, final String path, Charset encoding) throws IOException {
	return parse(COMPILATION_UNIT, resourceProvider(classLoader, path, encoding));
	}

	/**
	* Parses Java code from a Reader and returns a
	* {@link CompilationUnit} that represents it.<br>
	*
	* @param reader the reader containing Java source code. It will be closed after parsing.
	* @return CompilationUnit representing the Java source code
	* @throws ParseProblemException if the source code has parser errors
	*/
	public ParseResult<CompilationUnit> parse(final Reader reader) {
	return parse(COMPILATION_UNIT, provider(reader));
	}

	/**
	* Parses the Java code contained in code and returns a
	* {@link CompilationUnit} that represents it.
	*
	* @param code Java source code
	* @return CompilationUnit representing the Java source code
	* @throws ParseProblemException if the source code has parser errors
	*/
	public ParseResult<CompilationUnit> parse(String code) {
	return parse(COMPILATION_UNIT, provider(code));
	}

	/**
	* Parses the Java block contained in a {@link String} and returns a
	* {@link BlockStmt} that represents it.
	*
	* @param blockStatement {@link String} containing Java block code
	* @return BlockStmt representing the Java block
	* @throws ParseProblemException if the source code has parser errors
	*/
	public ParseResult<BlockStmt> parseBlock(final String blockStatement) {
	return parse(BLOCK, provider(blockStatement));
	}

	/**
	* Parses the Java statement contained in a {@link String} and returns a
	* {@link Statement} that represents it.
	*
	* @param statement {@link String} containing Java statement code
	* @return Statement representing the Java statement
	* @throws ParseProblemException if the source code has parser errors
	*/
	public ParseResult<Statement> parseStatement(final String statement) {
	return parse(STATEMENT, provider(statement));
	}

	/**
	* Parses the Java import contained in a {@link String} and returns a
	* {@link ImportDeclaration} that represents it.
	*
	* @param importDeclaration {@link String} containing Java import code
	* @return ImportDeclaration representing the Java import declaration
	* @throws ParseProblemException if the source code has parser errors
	*/
	public ParseResult<ImportDeclaration> parseImport(final String importDeclaration) {
	return parse(IMPORT_DECLARATION, provider(importDeclaration));
	}

	/**
	* Parses the Java expression contained in a {@link String} and returns a
	* {@link Expression} that represents it.
	*
	* @param expression {@link String} containing Java expression
	* @return Expression representing the Java expression
	* @throws ParseProblemException if the source code has parser errors
	*/
	@SuppressWarnings("unchecked")
	public <T extends Expression> ParseResult<T> parseExpression(final String expression) {
	return (ParseResult<T>) parse(EXPRESSION, provider(expression));
	}

	/**
	* Parses the Java annotation contained in a {@link String} and returns a
	* {@link AnnotationExpr} that represents it.
	*
	* @param annotation {@link String} containing Java annotation
	* @return AnnotationExpr representing the Java annotation
	* @throws ParseProblemException if the source code has parser errors
	*/
	public ParseResult<AnnotationExpr> parseAnnotation(final String annotation) {
	return parse(ANNOTATION, provider(annotation));
	}

	/**
	* Parses the Java annotation body declaration(e.g fields or methods) contained in a
	* {@link String} and returns a {@link BodyDeclaration} that represents it.
	*
	* @param body {@link String} containing Java body declaration
	* @return BodyDeclaration representing the Java annotation
	* @throws ParseProblemException if the source code has parser errors
	*/
	public ParseResult<BodyDeclaration<?>> parseAnnotationBodyDeclaration(final String body) {
	return parse(ANNOTATION_BODY, provider(body));
	}

	/**
	* Parses a Java class or interface body declaration(e.g fields or methods) and returns a
	* {@link BodyDeclaration} that represents it.
	*
	* @param body the body of a class or interface
	* @return BodyDeclaration representing the Java interface body
	* @throws ParseProblemException if the source code has parser errors
	*/
	@SuppressWarnings("unchecked")
	public <T extends BodyDeclaration<?>> ParseResult<T> parseBodyDeclaration(String body) {
	return (ParseResult<T>) parse(CLASS_BODY, provider(body));
	}

	/**
	* Parses a Java class or interface type name and returns a {@link ClassOrInterfaceType} that represents it.
	*
	* @param type the type name like a.b.c.X or Y
	* @return ClassOrInterfaceType representing the type
	* @throws ParseProblemException if the source code has parser errors
	*/
	public ParseResult<ClassOrInterfaceType> parseClassOrInterfaceType(String type) {
	return parse(CLASS_OR_INTERFACE_TYPE, provider(type));
	}

	/**
	* Parses a Java type name and returns a {@link Type} that represents it.
	*
	* @param type the type name like a.b.c.X, Y, or int
	* @return ClassOrInterfaceType representing the type
	* @throws ParseProblemException if the source code has parser errors
	*/
	public ParseResult<Type> parseType(String type) {
	return parse(TYPE, provider(type));
	}

	/**
	* Parses a variable declaration expression and returns a {@link com.github.javaparser.ast.expr.VariableDeclarationExpr}
	* that represents it.
	*
	* @param declaration a variable declaration like {@code int x=2;}
	* @return VariableDeclarationExpr representing the type
	* @throws ParseProblemException if the source code has parser errors
	*/
	public ParseResult<VariableDeclarationExpr> parseVariableDeclarationExpr(String declaration) {
	return parse(VARIABLE_DECLARATION_EXPR, provider(declaration));
	}

	/**
	* Parses the this(...) and super(...) statements that may occur at the start of a constructor.
	*
	* @param statement a statement like super("hello");
	* @return the AST for the statement.
	* @throws ParseProblemException if the source code has parser errors
	*/
	public ParseResult<ExplicitConstructorInvocationStmt> parseExplicitConstructorInvocationStmt(String statement) {
	return parse(EXPLICIT_CONSTRUCTOR_INVOCATION_STMT, provider(statement));
	}

	/**
	* Parses a qualified name (one that can have "."s in it) and returns it as a Name.
	*
	* @param qualifiedName a name like "com.laamella.parameter_source"
	* @return the AST for the name
	* @throws ParseProblemException if the source code has parser errors
	*/
	public ParseResult<Name> parseName(String qualifiedName) {
	return parse(NAME, provider(qualifiedName));
	}

	/**
	* Parses a simple name (one that can NOT have "."s in it) and returns it as a SimpleName.
	*
	* @param name a name like "parameter_source"
	* @return the AST for the name
	* @throws ParseProblemException if the source code has parser errors
	*/
	public ParseResult<SimpleName> parseSimpleName(String name) {
	return parse(SIMPLE_NAME, provider(name));
	}

	/**
	* Parses a single parameter (a type and a name) and returns it as a Parameter.
	*
	* @param parameter a parameter like "int[] x"
	* @return the AST for the parameter
	* @throws ParseProblemException if the source code has parser errors
	*/
	public ParseResult<Parameter> parseParameter(String parameter) {
	return parse(PARAMETER, provider(parameter));
	}

	/**
	* Parses a package declaration and returns it as a PackageDeclaration.
	*
	* @param packageDeclaration a declaration like "package com.microsoft.java;"
	* @return the AST for the parameter
	* @throws ParseProblemException if the source code has parser errors
	*/
	public ParseResult<PackageDeclaration> parsePackageDeclaration(String packageDeclaration) {
	return parse(PACKAGE_DECLARATION, provider(packageDeclaration));
	}

	/**
	* Parses a type declaration and returns it as a TypeDeclaration.
	*
	* @param typeDeclaration a declaration like "class X {}"
	* @return the AST for the type declaration
	* @throws ParseProblemException if the source code has parser errors
	*/
	public ParseResult<TypeDeclaration<?>> parseTypeDeclaration(String typeDeclaration) {
	return parse(TYPE_DECLARATION, provider(typeDeclaration));
	}

	/**
	* Parses a module declaration and returns it as a ModuleDeclaration.
	*
	* @param moduleDeclaration a declaration like "module X {}"
	* @return the AST for the module declaration
	* @throws ParseProblemException if the source code has parser errors
	* @see ModuleDeclaration
	*/
	public ParseResult<ModuleDeclaration> parseModuleDeclaration(String moduleDeclaration) {
	return parse(MODULE_DECLARATION, provider(moduleDeclaration));
	}

	/**
	* Parses a module directive and returns it as a ModuleDirective.
	*
	* @param moduleDirective a directive like "opens C;"
	* @return the AST for the module directive
	* @throws ParseProblemException if the source code has parser errors
	* @see ModuleDirective
	*/
	public ParseResult<ModuleDirective> parseModuleDirective(String moduleDirective) {
	return parse(MODULE_DIRECTIVE, provider(moduleDirective));
	}


	/**
	* Parses a type parameter and returns it as a TypeParameter
	*
	* @param typeParameter a parameter like "T extends Serializable"
	* @return the AST for the type parameter
	* @throws ParseProblemException if the source code has parser errors
	*/
	public ParseResult<TypeParameter> parseTypeParameter(String typeParameter) {
	return parse(TYPE_PARAMETER, provider(typeParameter));
	}

	/**
	* Parses a method declaration and returns it as a MethodDeclaration.
	*
	* @param methodDeclaration a method declaration like "void foo() {}"
	* @return the AST for the method declaration
	* @throws ParseProblemException if the source code has parser errors
	* @see MethodDeclaration
	*/
	public ParseResult<MethodDeclaration> parseMethodDeclaration(String methodDeclaration) {
	return parse(METHOD_DECLARATION, provider(methodDeclaration));
	}

	}

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