test/langtools/tools/javac/lambda/bridge/template_tests/BridgeMethodTestCase.java - platform/libcore - Git at Google

 /*
  * Copyright (c) 2013, 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.File;
 import java.io.IOException;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.StringJoiner;

 import org.testng.annotations.BeforeMethod;
 import org.testng.annotations.Test;

 import tools.javac.combo.*;

 import static org.testng.Assert.fail;

 /**
  * BridgeMethodTestCase -- used for asserting linkage to bridges under separate compilation.
  *
  * Example test case:
  *     public void test1() throws IOException, ReflectiveOperationException {
  *         compileSpec("C(Bc1(A))");
  *         assertLinkage("C", LINKAGE_ERROR, "B1");
  *         recompileSpec("C(Bc1(Ac0))", "A");
  *          assertLinkage("C", "A0", "B1");
  *     }
  *
  * This compiles A, B, and C, asserts that C.m()Object does not exist, asserts
  * that C.m()Number eventually invokes B.m()Number, recompiles B, and then asserts
  * that the result of calling C.m()Object now arrives at A.
  *
  * @author Brian Goetz
  */

 @Test
 public abstract class BridgeMethodTestCase extends JavacTemplateTestBase {

     private static final String TYPE_LETTERS = "ABCDIJK";

     private static final String BASE_INDEX_CLASS = "class C0 {\n" +
                                                    "    int val;\n" +
                                                    "    C0(int val) { this.val = val; }\n" +
                                                    "    public int getVal() { return val; }\n" +
                                                    "}\n";
     private static final String INDEX_CLASS_TEMPLATE = "class C#ID extends C#PREV {\n" +
                                                        "    C#ID(int val) { super(val); }\n" +
                                                        "}\n";


     protected static String LINKAGE_ERROR = "-1";

     private List<File> compileDirs = new ArrayList<>();

     /**
      * Compile all the classes in a class spec, and put them on the classpath.
      *
      * The spec is the specification for a nest of classes, using the following notation
      * A, B represent abstract classes
      * C represents a concrete class
      * I, J, K represent interfaces
      * Lowercase 'c' following a class means that the method m() is concrete
      * Lowercase 'a' following a class or interface means that the method m() is abstract
      * Lowercase 'd' following an interface means that the method m() is default
      * A number 0, 1, or 2 following the lowercase letter indicates the return type of that method
      * 0 = Object, 1 = Number, 2 = Integer (these form an inheritance chain so bridges are generated)
      * A classes supertypes follow its method spec, in parentheses
      * Examples:
      *   C(Ia0, Jd0) -- C extends I and J, I has abstract m()Object, J has default m()Object
      *   Cc1(Ia0) -- C has concrete m()Number, extends I with abstract m()Object
      * If a type must appear multiple times, its full spec must be in the first occurrence
      * Example:
      *   C(I(Kd0), J(K))
      */
    protected void compileSpec(String spec) throws IOException {
         compileSpec(spec, false);
     }

     /**
      * Compile all the classes in a class spec, and assert that there were compilation errors.
      */
     protected void compileSpec(String spec, String... errorKeys) throws IOException {
         compileSpec(spec, false, errorKeys);
     }

     protected void compileSpec(String spec, boolean debug, String... errorKeys) throws IOException {
         ClassModel cm = new Parser(spec).parseClassModel();
         for (int i = 0; i <= cm.maxIndex() ; i++) {
             if (debug) System.out.println(indexClass(i));
             addSourceFile(String.format("C%d.java", i), new StringTemplate(indexClass(i)));
         }
         for (Map.Entry<String, ClassModel> e : classes(cm).entrySet()) {
             if (debug) System.out.println(e.getValue().toSource());
             addSourceFile(e.getKey() + ".java", new StringTemplate(e.getValue().toSource()));
         }
         compileDirs.add(compile(true));
         resetSourceFiles();
         if (errorKeys.length == 0)
             assertCompileSucceeded();
         else
             assertCompileErrors(errorKeys);
     }

     /**
      * Recompile only a subset of classes in the class spec, as named by names,
      * and put them on the classpath such that they shadow earlier versions of that class.
      */
     protected void recompileSpec(String spec, String... names) throws IOException {
         List<String> nameList = Arrays.asList(names);
         ClassModel cm = new Parser(spec).parseClassModel();
         for (int i = 0; i <= cm.maxIndex() ; i++) {
             addSourceFile(String.format("C%d.java", i), new StringTemplate(indexClass(i)));
         }
         for (Map.Entry<String, ClassModel> e : classes(cm).entrySet())
             if (nameList.contains(e.getKey()))
                 addSourceFile(e.getKey() + ".java", new StringTemplate(e.getValue().toSource()));
         compileDirs.add(compile(Arrays.asList(classPaths()), true));
         resetSourceFiles();
         assertCompileSucceeded();
     }

     protected void assertLinkage(String name, String... expected) throws ReflectiveOperationException {
         for (int i=0; i<expected.length; i++) {
             String e = expected[i];
             if (e.equals(LINKAGE_ERROR)) {
                 try {
                     int actual = invoke(name, i);
                     fail("Expected linkage error, got" + fromNum(actual));
                 }
                 catch (LinkageError x) {
                     // success
                 }
             }
             else {
                 if (e.length() == 1)
                     e += "0";
                 int expectedInt = toNum(e);
                 int actual = invoke(name, i);
                 if (expectedInt != actual)
                     fail(String.format("Expected %s but found %s for %s.m()%d", fromNum(expectedInt), fromNum(actual), name, i));
             }
         }
     }

     private Map<String, ClassModel> classes(ClassModel cm) {
         HashMap<String, ClassModel> m = new HashMap<>();
         classesHelper(cm, m);
         return m;
     }

     private String indexClass(int index) {
         if (index == 0) {
             return BASE_INDEX_CLASS;
         } else {
             return INDEX_CLASS_TEMPLATE
                     .replace("#ID", String.valueOf(index))
                     .replace("#PREV", String.valueOf(index - 1));
         }
     }

     private static String overrideName(int index) {
         return "C" + index;
     }

     private void classesHelper(ClassModel cm, Map<String, ClassModel> m) {
         if (!m.containsKey(cm.name))
             m.put(cm.name, cm);
         for (ClassModel s : cm.supertypes)
             classesHelper(s, m);
     }

     private static String fromNum(int num) {
         return String.format("%c%d", TYPE_LETTERS.charAt(num / 10), num % 10);
     }

     private static int toNum(String name, int index) {
         return 10*(TYPE_LETTERS.indexOf(name.charAt(0))) + index;
     }

     private static int toNum(String string) {
         return 10*(TYPE_LETTERS.indexOf(string.charAt(0))) + Integer.parseInt(string.substring(1, 2));
     }

     private int invoke(String name, int index) throws ReflectiveOperationException {
         File[] files = classPaths();
         Class clazz = loadClass(name, files);
         Method[] ms = clazz.getMethods();
         for (Method m : ms) {
             if (m.getName().equals("m") && m.getReturnType().getName().equals(overrideName(index))) {
                 m.setAccessible(true);
                 Object instance = clazz.newInstance();
                 Object c0 = m.invoke(instance);
                 Method getVal = c0.getClass().getMethod("getVal");
                 getVal.setAccessible(true);
                 return (int)getVal.invoke(c0);
             }
         }
         throw new NoSuchMethodError("cannot find method m()" + index + " in class " + name);
     }

     private File[] classPaths() {
         File[] files = new File[compileDirs.size()];
         for (int i=0; i<files.length; i++)
             files[files.length - i - 1] = compileDirs.get(i);
         return files;
     }

     @BeforeMethod
     @Override
     public void reset() {
         compileDirs.clear();
         super.reset();
     }

     private static class ClassModel {

         enum MethodType {
             ABSTRACT('a'), CONCRETE('c'), DEFAULT('d');

             public final char designator;

             MethodType(char designator) {
                 this.designator = designator;
             }

             public static MethodType find(char c) {
                 for (MethodType m : values())
                     if (m.designator == c)
                         return m;
                 throw new IllegalArgumentException();
             }
         }

         private final String name;
         private final boolean isInterface;
         private final List<ClassModel> supertypes;
         private final MethodType methodType;
         private final int methodIndex;

         private ClassModel(String name,
                            boolean anInterface,
                            List<ClassModel> supertypes,
                            MethodType methodType,
                            int methodIndex) {
             this.name = name;
             isInterface = anInterface;
             this.supertypes = supertypes;
             this.methodType = methodType;
             this.methodIndex = methodIndex;
         }

         @Override
         public String toString() {
             StringBuilder sb = new StringBuilder();
             sb.append(name);
             if (methodType != null) {
                 sb.append(methodType.designator);
                 sb.append(methodIndex);
             }
             if (!supertypes.isEmpty()) {
                 sb.append("(");
                 for (int i=0; i<supertypes.size(); i++) {
                     if (i > 0)
                         sb.append(",");
                     sb.append(supertypes.get(i).toString());
                 }
                 sb.append(")");
             }
             return sb.toString();
         }

         int maxIndex() {
             int maxSoFar = methodIndex;
             for (ClassModel cm : supertypes) {
                 maxSoFar = Math.max(cm.maxIndex(), maxSoFar);
             }
             return maxSoFar;
         }

         public String toSource() {
             String extendsClause = "";
             String implementsClause = "";
             String methodBody = "";
             boolean isAbstract = "AB".contains(name);

             for (ClassModel s : supertypes) {
                 if (!s.isInterface) {
                     extendsClause = String.format("extends %s", s.name);
                     break;
                 }
             }

             StringJoiner sj = new StringJoiner(", ");
             for (ClassModel s : supertypes)
                 if (s.isInterface)
                     sj.add(s.name);
             if (sj.length() > 0) {
                 if (isInterface)
                     implementsClause = "extends " + sj.toString();
                 else
                 implementsClause = "implements " + sj.toString();
             }
             if (methodType != null) {
                 switch (methodType) {
                     case ABSTRACT:
                         methodBody = String.format("public abstract %s m();", overrideName(methodIndex));
                         break;
                     case CONCRETE:
                         methodBody = String.format("public %s m() { return new %s(%d); };",
                                 overrideName(methodIndex), overrideName(methodIndex), toNum(name, methodIndex));
                         break;
                     case DEFAULT:
                         methodBody = String.format("public default %s m() { return new %s(%d); };",
                                 overrideName(methodIndex), overrideName(methodIndex), toNum(name, methodIndex));
                         break;

                 }
             }

             return String.format("public %s %s %s %s %s {  %s }", isAbstract ? "abstract" : "",
                                  isInterface ? "interface" : "class",
                                  name, extendsClause, implementsClause, methodBody);
         }
     }

     private static class Parser {
         private final String input;
         private final char[] chars;
         private int index;

         private Parser(String s) {
             input = s;
             chars = s.toCharArray();
         }

         private char peek() {
             return index < chars.length ? chars[index] : 0;
         }

         private boolean peek(String validChars) {
             return validChars.indexOf(peek()) >= 0;
         }

         private char advanceIf(String validChars) {
             if (peek(validChars))
                 return chars[index++];
             else
                 return 0;
         }

         private char advanceIfDigit() {
             return advanceIf("0123456789");
         }

         private int index() {
             StringBuilder buf = new StringBuilder();
             char c = advanceIfDigit();
             while (c != 0) {
                 buf.append(c);
                 c = advanceIfDigit();
             }
             return Integer.valueOf(buf.toString());
         }

         private char advance() {
             return chars[index++];
         }

         private char expect(String validChars) {
             char c = advanceIf(validChars);
             if (c == 0)
                 throw new IllegalArgumentException(String.format("Expecting %s at position %d of %s", validChars, index, input));
             return c;
         }

         public ClassModel parseClassModel() {
             List<ClassModel> supers = new ArrayList<>();
             char name = expect(TYPE_LETTERS);
             boolean isInterface = "IJK".indexOf(name) >= 0;
             ClassModel.MethodType methodType = peek(isInterface ? "ad" : "ac") ? ClassModel.MethodType.find(advance()) : null;
             int methodIndex = 0;
             if (methodType != null) {
                 methodIndex = index();
             }
             if (peek() == '(') {
                 advance();
                 supers.add(parseClassModel());
                 while (peek() == ',') {
                     advance();
                     supers.add(parseClassModel());
                 }
                 expect(")");
             }
             return new ClassModel(new String(new char[]{ name }), isInterface, supers, methodType, methodIndex);
         }
     }
 }
	/*
	* Copyright (c) 2013, 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.File;
	import java.io.IOException;
	import java.lang.reflect.Method;
	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.HashMap;
	import java.util.List;
	import java.util.Map;
	import java.util.StringJoiner;

	import org.testng.annotations.BeforeMethod;
	import org.testng.annotations.Test;

	import tools.javac.combo.*;

	import static org.testng.Assert.fail;

	/**
	* BridgeMethodTestCase -- used for asserting linkage to bridges under separate compilation.
	*
	* Example test case:
	* public void test1() throws IOException, ReflectiveOperationException {
	* compileSpec("C(Bc1(A))");
	* assertLinkage("C", LINKAGE_ERROR, "B1");
	* recompileSpec("C(Bc1(Ac0))", "A");
	* assertLinkage("C", "A0", "B1");
	* }
	*
	* This compiles A, B, and C, asserts that C.m()Object does not exist, asserts
	* that C.m()Number eventually invokes B.m()Number, recompiles B, and then asserts
	* that the result of calling C.m()Object now arrives at A.
	*
	* @author Brian Goetz
	*/

	@Test
	public abstract class BridgeMethodTestCase extends JavacTemplateTestBase {

	private static final String TYPE_LETTERS = "ABCDIJK";

	private static final String BASE_INDEX_CLASS = "class C0 {\n" +
	" int val;\n" +
	" C0(int val) { this.val = val; }\n" +
	" public int getVal() { return val; }\n" +
	"}\n";
	private static final String INDEX_CLASS_TEMPLATE = "class C#ID extends C#PREV {\n" +
	" C#ID(int val) { super(val); }\n" +
	"}\n";



	protected static String LINKAGE_ERROR = "-1";

	private List<File> compileDirs = new ArrayList<>();

	/**
	* Compile all the classes in a class spec, and put them on the classpath.
	*
	* The spec is the specification for a nest of classes, using the following notation
	* A, B represent abstract classes
	* C represents a concrete class
	* I, J, K represent interfaces
	* Lowercase 'c' following a class means that the method m() is concrete
	* Lowercase 'a' following a class or interface means that the method m() is abstract
	* Lowercase 'd' following an interface means that the method m() is default
	* A number 0, 1, or 2 following the lowercase letter indicates the return type of that method
	* 0 = Object, 1 = Number, 2 = Integer (these form an inheritance chain so bridges are generated)
	* A classes supertypes follow its method spec, in parentheses
	* Examples:
	* C(Ia0, Jd0) -- C extends I and J, I has abstract m()Object, J has default m()Object
	* Cc1(Ia0) -- C has concrete m()Number, extends I with abstract m()Object
	* If a type must appear multiple times, its full spec must be in the first occurrence
	* Example:
	* C(I(Kd0), J(K))
	*/
	protected void compileSpec(String spec) throws IOException {
	compileSpec(spec, false);
	}

	/**
	* Compile all the classes in a class spec, and assert that there were compilation errors.
	*/
	protected void compileSpec(String spec, String... errorKeys) throws IOException {
	compileSpec(spec, false, errorKeys);
	}

	protected void compileSpec(String spec, boolean debug, String... errorKeys) throws IOException {
	ClassModel cm = new Parser(spec).parseClassModel();
	for (int i = 0; i <= cm.maxIndex() ; i++) {
	if (debug) System.out.println(indexClass(i));
	addSourceFile(String.format("C%d.java", i), new StringTemplate(indexClass(i)));
	}
	for (Map.Entry<String, ClassModel> e : classes(cm).entrySet()) {
	if (debug) System.out.println(e.getValue().toSource());
	addSourceFile(e.getKey() + ".java", new StringTemplate(e.getValue().toSource()));
	}
	compileDirs.add(compile(true));
	resetSourceFiles();
	if (errorKeys.length == 0)
	assertCompileSucceeded();
	else
	assertCompileErrors(errorKeys);
	}

	/**
	* Recompile only a subset of classes in the class spec, as named by names,
	* and put them on the classpath such that they shadow earlier versions of that class.
	*/
	protected void recompileSpec(String spec, String... names) throws IOException {
	List<String> nameList = Arrays.asList(names);
	ClassModel cm = new Parser(spec).parseClassModel();
	for (int i = 0; i <= cm.maxIndex() ; i++) {
	addSourceFile(String.format("C%d.java", i), new StringTemplate(indexClass(i)));
	}
	for (Map.Entry<String, ClassModel> e : classes(cm).entrySet())
	if (nameList.contains(e.getKey()))
	addSourceFile(e.getKey() + ".java", new StringTemplate(e.getValue().toSource()));
	compileDirs.add(compile(Arrays.asList(classPaths()), true));
	resetSourceFiles();
	assertCompileSucceeded();
	}

	protected void assertLinkage(String name, String... expected) throws ReflectiveOperationException {
	for (int i=0; i<expected.length; i++) {
	String e = expected[i];
	if (e.equals(LINKAGE_ERROR)) {
	try {
	int actual = invoke(name, i);
	fail("Expected linkage error, got" + fromNum(actual));
	}
	catch (LinkageError x) {
	// success
	}
	}
	else {
	if (e.length() == 1)
	e += "0";
	int expectedInt = toNum(e);
	int actual = invoke(name, i);
	if (expectedInt != actual)
	fail(String.format("Expected %s but found %s for %s.m()%d", fromNum(expectedInt), fromNum(actual), name, i));
	}
	}
	}

	private Map<String, ClassModel> classes(ClassModel cm) {
	HashMap<String, ClassModel> m = new HashMap<>();
	classesHelper(cm, m);
	return m;
	}

	private String indexClass(int index) {
	if (index == 0) {
	return BASE_INDEX_CLASS;
	} else {
	return INDEX_CLASS_TEMPLATE
	.replace("#ID", String.valueOf(index))
	.replace("#PREV", String.valueOf(index - 1));
	}
	}

	private static String overrideName(int index) {
	return "C" + index;
	}

	private void classesHelper(ClassModel cm, Map<String, ClassModel> m) {
	if (!m.containsKey(cm.name))
	m.put(cm.name, cm);
	for (ClassModel s : cm.supertypes)
	classesHelper(s, m);
	}

	private static String fromNum(int num) {
	return String.format("%c%d", TYPE_LETTERS.charAt(num / 10), num % 10);
	}

	private static int toNum(String name, int index) {
	return 10*(TYPE_LETTERS.indexOf(name.charAt(0))) + index;
	}

	private static int toNum(String string) {
	return 10*(TYPE_LETTERS.indexOf(string.charAt(0))) + Integer.parseInt(string.substring(1, 2));
	}

	private int invoke(String name, int index) throws ReflectiveOperationException {
	File[] files = classPaths();
	Class clazz = loadClass(name, files);
	Method[] ms = clazz.getMethods();
	for (Method m : ms) {
	if (m.getName().equals("m") && m.getReturnType().getName().equals(overrideName(index))) {
	m.setAccessible(true);
	Object instance = clazz.newInstance();
	Object c0 = m.invoke(instance);
	Method getVal = c0.getClass().getMethod("getVal");
	getVal.setAccessible(true);
	return (int)getVal.invoke(c0);
	}
	}
	throw new NoSuchMethodError("cannot find method m()" + index + " in class " + name);
	}

	private File[] classPaths() {
	File[] files = new File[compileDirs.size()];
	for (int i=0; i<files.length; i++)
	files[files.length - i - 1] = compileDirs.get(i);
	return files;
	}

	@BeforeMethod
	@Override
	public void reset() {
	compileDirs.clear();
	super.reset();
	}

	private static class ClassModel {

	enum MethodType {
	ABSTRACT('a'), CONCRETE('c'), DEFAULT('d');

	public final char designator;

	MethodType(char designator) {
	this.designator = designator;
	}

	public static MethodType find(char c) {
	for (MethodType m : values())
	if (m.designator == c)
	return m;
	throw new IllegalArgumentException();
	}
	}

	private final String name;
	private final boolean isInterface;
	private final List<ClassModel> supertypes;
	private final MethodType methodType;
	private final int methodIndex;

	private ClassModel(String name,
	boolean anInterface,
	List<ClassModel> supertypes,
	MethodType methodType,
	int methodIndex) {
	this.name = name;
	isInterface = anInterface;
	this.supertypes = supertypes;
	this.methodType = methodType;
	this.methodIndex = methodIndex;
	}

	@Override
	public String toString() {
	StringBuilder sb = new StringBuilder();
	sb.append(name);
	if (methodType != null) {
	sb.append(methodType.designator);
	sb.append(methodIndex);
	}
	if (!supertypes.isEmpty()) {
	sb.append("(");
	for (int i=0; i<supertypes.size(); i++) {
	if (i > 0)
	sb.append(",");
	sb.append(supertypes.get(i).toString());
	}
	sb.append(")");
	}
	return sb.toString();
	}

	int maxIndex() {
	int maxSoFar = methodIndex;
	for (ClassModel cm : supertypes) {
	maxSoFar = Math.max(cm.maxIndex(), maxSoFar);
	}
	return maxSoFar;
	}

	public String toSource() {
	String extendsClause = "";
	String implementsClause = "";
	String methodBody = "";
	boolean isAbstract = "AB".contains(name);

	for (ClassModel s : supertypes) {
	if (!s.isInterface) {
	extendsClause = String.format("extends %s", s.name);
	break;
	}
	}

	StringJoiner sj = new StringJoiner(", ");
	for (ClassModel s : supertypes)
	if (s.isInterface)
	sj.add(s.name);
	if (sj.length() > 0) {
	if (isInterface)
	implementsClause = "extends " + sj.toString();
	else
	implementsClause = "implements " + sj.toString();
	}
	if (methodType != null) {
	switch (methodType) {
	case ABSTRACT:
	methodBody = String.format("public abstract %s m();", overrideName(methodIndex));
	break;
	case CONCRETE:
	methodBody = String.format("public %s m() { return new %s(%d); };",
	overrideName(methodIndex), overrideName(methodIndex), toNum(name, methodIndex));
	break;
	case DEFAULT:
	methodBody = String.format("public default %s m() { return new %s(%d); };",
	overrideName(methodIndex), overrideName(methodIndex), toNum(name, methodIndex));
	break;

	}
	}

	return String.format("public %s %s %s %s %s { %s }", isAbstract ? "abstract" : "",
	isInterface ? "interface" : "class",
	name, extendsClause, implementsClause, methodBody);
	}
	}

	private static class Parser {
	private final String input;
	private final char[] chars;
	private int index;

	private Parser(String s) {
	input = s;
	chars = s.toCharArray();
	}

	private char peek() {
	return index < chars.length ? chars[index] : 0;
	}

	private boolean peek(String validChars) {
	return validChars.indexOf(peek()) >= 0;
	}

	private char advanceIf(String validChars) {
	if (peek(validChars))
	return chars[index++];
	else
	return 0;
	}

	private char advanceIfDigit() {
	return advanceIf("0123456789");
	}

	private int index() {
	StringBuilder buf = new StringBuilder();
	char c = advanceIfDigit();
	while (c != 0) {
	buf.append(c);
	c = advanceIfDigit();
	}
	return Integer.valueOf(buf.toString());
	}

	private char advance() {
	return chars[index++];
	}

	private char expect(String validChars) {
	char c = advanceIf(validChars);
	if (c == 0)
	throw new IllegalArgumentException(String.format("Expecting %s at position %d of %s", validChars, index, input));
	return c;
	}

	public ClassModel parseClassModel() {
	List<ClassModel> supers = new ArrayList<>();
	char name = expect(TYPE_LETTERS);
	boolean isInterface = "IJK".indexOf(name) >= 0;
	ClassModel.MethodType methodType = peek(isInterface ? "ad" : "ac") ? ClassModel.MethodType.find(advance()) : null;
	int methodIndex = 0;
	if (methodType != null) {
	methodIndex = index();
	}
	if (peek() == '(') {
	advance();
	supers.add(parseClassModel());
	while (peek() == ',') {
	advance();
	supers.add(parseClassModel());
	}
	expect(")");
	}
	return new ClassModel(new String(new char[]{ name }), isInterface, supers, methodType, methodIndex);
	}
	}
	}