TokenUtil.java
///////////////////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
// Copyright (C) 2001-2022 the original author or authors.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library 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.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
///////////////////////////////////////////////////////////////////////////////////////////////
package com.puppycrawl.tools.checkstyle.utils;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Locale;
import java.util.Map;
import java.util.Optional;
import java.util.ResourceBundle;
import java.util.function.Consumer;
import java.util.function.Predicate;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import com.puppycrawl.tools.checkstyle.api.DetailAST;
import com.puppycrawl.tools.checkstyle.api.TokenTypes;
/**
* Contains utility methods for tokens.
*
*/
public final class TokenUtil {
/** Maps from a token name to value. */
private static final Map<String, Integer> TOKEN_NAME_TO_VALUE;
/** Maps from a token value to name. */
private static final Map<Integer, String> TOKEN_VALUE_TO_NAME;
/** Array of all token IDs. */
private static final int[] TOKEN_IDS;
/** Format for exception message when getting token by given id. */
private static final String TOKEN_ID_EXCEPTION_FORMAT = "unknown TokenTypes id '%s'";
/** Format for exception message when getting token by given name. */
private static final String TOKEN_NAME_EXCEPTION_FORMAT = "unknown TokenTypes value '%s'";
// initialise the constants
static {
TOKEN_NAME_TO_VALUE = nameToValueMapFromPublicIntFields(TokenTypes.class);
TOKEN_VALUE_TO_NAME = invertMap(TOKEN_NAME_TO_VALUE);
TOKEN_IDS = TOKEN_NAME_TO_VALUE.values().stream().mapToInt(Integer::intValue).toArray();
}
/** Stop instances being created. **/
private TokenUtil() {
}
/**
* Gets the value of a static or instance field of type int or of another primitive type
* convertible to type int via a widening conversion. Does not throw any checked exceptions.
*
* @param field from which the int should be extracted
* @param object to extract the int value from
* @return the value of the field converted to type int
* @throws IllegalStateException if this Field object is enforcing Java language access control
* and the underlying field is inaccessible
* @see Field#getInt(Object)
*/
public static int getIntFromField(Field field, Object object) {
try {
return field.getInt(object);
}
catch (final IllegalAccessException exception) {
throw new IllegalStateException(exception);
}
}
/**
* Creates a map of 'field name' to 'field value' from all {@code public} {@code int} fields
* of a class.
*
* @param cls source class
* @return unmodifiable name to value map
*/
public static Map<String, Integer> nameToValueMapFromPublicIntFields(Class<?> cls) {
return Arrays.stream(cls.getDeclaredFields())
.filter(fld -> Modifier.isPublic(fld.getModifiers()) && fld.getType() == Integer.TYPE)
.collect(Collectors.toUnmodifiableMap(
Field::getName, fld -> getIntFromField(fld, fld.getName()))
);
}
/**
* Inverts a given map by exchanging each entry's key and value.
*
* @param map source map
* @return inverted map
*/
public static Map<Integer, String> invertMap(Map<String, Integer> map) {
return map.entrySet().stream()
.collect(Collectors.toMap(Map.Entry::getValue, Map.Entry::getKey));
}
/**
* Get total number of TokenTypes.
*
* @return total number of TokenTypes.
*/
public static int getTokenTypesTotalNumber() {
return TOKEN_IDS.length;
}
/**
* Get all token IDs that are available in TokenTypes.
*
* @return array of token IDs
*/
public static int[] getAllTokenIds() {
final int[] safeCopy = new int[TOKEN_IDS.length];
System.arraycopy(TOKEN_IDS, 0, safeCopy, 0, TOKEN_IDS.length);
return safeCopy;
}
/**
* Returns the name of a token for a given ID.
*
* @param id the ID of the token name to get
* @return a token name
* @throws IllegalArgumentException when id is not valid
*/
public static String getTokenName(int id) {
final String name = TOKEN_VALUE_TO_NAME.get(id);
if (name == null) {
throw new IllegalArgumentException(
String.format(Locale.ROOT, TOKEN_ID_EXCEPTION_FORMAT, id));
}
return name;
}
/**
* Returns the ID of a token for a given name.
*
* @param name the name of the token ID to get
* @return a token ID
* @throws IllegalArgumentException when id is null
*/
public static int getTokenId(String name) {
final Integer id = TOKEN_NAME_TO_VALUE.get(name);
if (id == null) {
throw new IllegalArgumentException(
String.format(Locale.ROOT, TOKEN_NAME_EXCEPTION_FORMAT, name));
}
return id;
}
/**
* Returns the short description of a token for a given name.
*
* @param name the name of the token ID to get
* @return a short description
* @throws IllegalArgumentException when name is unknown
*/
public static String getShortDescription(String name) {
if (!TOKEN_NAME_TO_VALUE.containsKey(name)) {
throw new IllegalArgumentException(
String.format(Locale.ROOT, TOKEN_NAME_EXCEPTION_FORMAT, name));
}
final String tokenTypes =
"com.puppycrawl.tools.checkstyle.api.tokentypes";
final ResourceBundle bundle = ResourceBundle.getBundle(tokenTypes, Locale.ROOT);
return bundle.getString(name);
}
/**
* Is argument comment-related type (SINGLE_LINE_COMMENT,
* BLOCK_COMMENT_BEGIN, BLOCK_COMMENT_END, COMMENT_CONTENT).
*
* @param type
* token type.
* @return true if type is comment-related type.
*/
public static boolean isCommentType(int type) {
return type == TokenTypes.SINGLE_LINE_COMMENT
|| type == TokenTypes.BLOCK_COMMENT_BEGIN
|| type == TokenTypes.BLOCK_COMMENT_END
|| type == TokenTypes.COMMENT_CONTENT;
}
/**
* Is argument comment-related type name (SINGLE_LINE_COMMENT,
* BLOCK_COMMENT_BEGIN, BLOCK_COMMENT_END, COMMENT_CONTENT).
*
* @param type
* token type name.
* @return true if type is comment-related type name.
*/
public static boolean isCommentType(String type) {
return isCommentType(getTokenId(type));
}
/**
* Finds the first {@link Optional} child token of {@link DetailAST} root node
* which matches the given predicate.
*
* @param root root node.
* @param predicate predicate.
* @return {@link Optional} of {@link DetailAST} node which matches the predicate.
*/
public static Optional<DetailAST> findFirstTokenByPredicate(DetailAST root,
Predicate<DetailAST> predicate) {
Optional<DetailAST> result = Optional.empty();
for (DetailAST ast = root.getFirstChild(); ast != null; ast = ast.getNextSibling()) {
if (predicate.test(ast)) {
result = Optional.of(ast);
break;
}
}
return result;
}
/**
* Performs an action for each child of {@link DetailAST} root node
* which matches the given token type.
*
* @param root root node.
* @param type token type to match.
* @param action action to perform on the nodes.
*/
public static void forEachChild(DetailAST root, int type, Consumer<DetailAST> action) {
for (DetailAST ast = root.getFirstChild(); ast != null; ast = ast.getNextSibling()) {
if (ast.getType() == type) {
action.accept(ast);
}
}
}
/**
* Determines if two ASTs are on the same line.
*
* @param ast1 the first AST
* @param ast2 the second AST
*
* @return true if they are on the same line.
*/
public static boolean areOnSameLine(DetailAST ast1, DetailAST ast2) {
return ast1.getLineNo() == ast2.getLineNo();
}
/**
* Is type declaration token type (CLASS_DEF, INTERFACE_DEF,
* ANNOTATION_DEF, ENUM_DEF, RECORD_DEF).
*
* @param type
* token type.
* @return true if type is type declaration token type.
*/
public static boolean isTypeDeclaration(int type) {
return type == TokenTypes.CLASS_DEF
|| type == TokenTypes.INTERFACE_DEF
|| type == TokenTypes.ANNOTATION_DEF
|| type == TokenTypes.ENUM_DEF
|| type == TokenTypes.RECORD_DEF;
}
/**
* Determines if the token type belongs to the given types.
*
* @param type the Token Type to check
* @param types the acceptable types
*
* @return true if type matches one of the given types.
*/
public static boolean isOfType(int type, int... types) {
boolean matching = false;
for (int tokenType : types) {
if (tokenType == type) {
matching = true;
break;
}
}
return matching;
}
/**
* Determines if the AST belongs to the given types.
*
* @param ast the AST node to check
* @param types the acceptable types
*
* @return true if type matches one of the given types.
*/
public static boolean isOfType(DetailAST ast, int... types) {
return ast != null && isOfType(ast.getType(), types);
}
/**
* Determines if given AST is a root node, i.e. if the type
* of the token we are checking is {@code COMPILATION_UNIT}.
*
* @param ast AST to check
* @return true if AST is a root node
*/
public static boolean isRootNode(DetailAST ast) {
return ast.getType() == TokenTypes.COMPILATION_UNIT;
}
/**
* Checks if a token type is a literal true or false.
*
* @param tokenType the TokenType
* @return true if tokenType is LITERAL_TRUE or LITERAL_FALSE
*/
public static boolean isBooleanLiteralType(final int tokenType) {
final boolean isTrue = tokenType == TokenTypes.LITERAL_TRUE;
final boolean isFalse = tokenType == TokenTypes.LITERAL_FALSE;
return isTrue || isFalse;
}
/**
* Creates a new {@code BitSet} from array of tokens.
*
* @param tokens to initialize the BitSet
* @return tokens as BitSet
*/
public static BitSet asBitSet(int... tokens) {
return IntStream.of(tokens)
.collect(BitSet::new, BitSet::set, BitSet::or);
}
/**
* Creates a new {@code BitSet} from array of tokens.
*
* @param tokens to initialize the BitSet
* @return tokens as BitSet
*/
public static BitSet asBitSet(String... tokens) {
return Arrays.stream(tokens)
.map(String::trim)
.filter(Predicate.not(String::isEmpty))
.mapToInt(TokenUtil::getTokenId)
.collect(BitSet::new, BitSet::set, BitSet::or);
}
}