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Checkstyle is a development tool to help programmers write Java code
that adheres to a coding standard
////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code for adherence to a set of rules.
// Copyright (C) 2001-2019 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.Collections;
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 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 TOKEN_NAME_TO_VALUE;
/** Maps from a token value to name. */
private static final String[] TOKEN_VALUE_TO_NAME;
/** Array of all token IDs. */
private static final int[] TOKEN_IDS;
/** Prefix for exception when getting token by given id. */
private static final String TOKEN_ID_EXCEPTION_PREFIX = "given id ";
/** Prefix for exception when getting token by given name. */
private static final String TOKEN_NAME_EXCEPTION_PREFIX = "given name ";
// initialise the constants
static {
TOKEN_NAME_TO_VALUE = nameToValueMapFromPublicIntFields(TokenTypes.class);
TOKEN_VALUE_TO_NAME = valueToNameArrayFromNameToValueMap(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 nameToValueMapFromPublicIntFields(Class cls) {
final Map map = Arrays.stream(cls.getDeclaredFields())
.filter(fld -> Modifier.isPublic(fld.getModifiers()) && fld.getType() == Integer.TYPE)
.collect(Collectors.toMap(Field::getName, fld -> getIntFromField(fld, fld.getName())));
return Collections.unmodifiableMap(map);
}
/**
* Creates an array of map keys for quick value-to-name lookup for the map.
* @param map source map
* @return array of map keys
*/
public static String[] valueToNameArrayFromNameToValueMap(Map map) {
String[] valueToNameArray = CommonUtil.EMPTY_STRING_ARRAY;
for (Map.Entry entry : map.entrySet()) {
final int value = entry.getValue();
// JavadocTokenTypes.EOF has value '-1' and is handled explicitly.
if (value >= 0) {
if (value >= valueToNameArray.length) {
final String[] temp = new String[value + 1];
System.arraycopy(valueToNameArray, 0, temp, 0, valueToNameArray.length);
valueToNameArray = temp;
}
valueToNameArray[value] = entry.getKey();
}
}
return valueToNameArray;
}
/**
* 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
*/
public static String getTokenName(int id) {
if (id > TOKEN_VALUE_TO_NAME.length - 1) {
throw new IllegalArgumentException(TOKEN_ID_EXCEPTION_PREFIX + id);
}
final String name = TOKEN_VALUE_TO_NAME[id];
if (name == null) {
throw new IllegalArgumentException(TOKEN_ID_EXCEPTION_PREFIX + 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
*/
public static int getTokenId(String name) {
final Integer id = TOKEN_NAME_TO_VALUE.get(name);
if (id == null) {
throw new IllegalArgumentException(TOKEN_NAME_EXCEPTION_PREFIX + 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
*/
public static String getShortDescription(String name) {
if (!TOKEN_NAME_TO_VALUE.containsKey(name)) {
throw new IllegalArgumentException(TOKEN_NAME_EXCEPTION_PREFIX + 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 findFirstTokenByPredicate(DetailAST root,
Predicate predicate) {
Optional 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 action) {
for (DetailAST ast = root.getFirstChild(); ast != null; ast = ast.getNextSibling()) {
if (ast.getType() == type) {
action.accept(ast);
}
}
}
}