001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2026 the original author or authors.
004//
005// This library is free software; you can redistribute it and/or
006// modify it under the terms of the GNU Lesser General Public
007// License as published by the Free Software Foundation; either
008// version 2.1 of the License, or (at your option) any later version.
009//
010// This library is distributed in the hope that it will be useful,
011// but WITHOUT ANY WARRANTY; without even the implied warranty of
012// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
013// Lesser General Public License for more details.
014//
015// You should have received a copy of the GNU Lesser General Public
016// License along with this library; if not, write to the Free Software
017// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
018///////////////////////////////////////////////////////////////////////////////////////////////
019
020package com.puppycrawl.tools.checkstyle.api;
021
022import javax.annotation.Nullable;
023
024/**
025 * An interface of Checkstyle's AST nodes for traversing trees generated from the
026 * Java code. The main purpose of this interface is to abstract away ANTLR
027 * specific classes from API package so other libraries won't require it.
028 *
029 * @see <a href="https://www.antlr.org/">ANTLR Website</a>
030 */
031public interface DetailAST {
032
033    /**
034     * Returns the number of child nodes one level below this node. That is,
035     * does not recurse down the tree.
036     *
037     * @return the number of child nodes
038     */
039    int getChildCount();
040
041    /**
042     * Returns the number of direct child tokens that have the specified type.
043     *
044     * @param type the token type to match
045     * @return the number of matching token
046     */
047    int getChildCount(int type);
048
049    /**
050     * Returns the parent token.
051     *
052     * @return the parent token
053     */
054    DetailAST getParent();
055
056    /**
057     * Gets the text of this AST.
058     *
059     * @return the text.
060     */
061    String getText();
062
063    /**
064     * Gets the type of this AST.
065     *
066     * @return the type.
067     */
068    int getType();
069
070    /**
071     * Gets line number.
072     *
073     * @return the line number
074     */
075    int getLineNo();
076
077    /**
078     * Gets column number.
079     *
080     * @return the column number
081     */
082    int getColumnNo();
083
084    /**
085     * Gets the last child node.
086     *
087     * @return the last child node
088     */
089    DetailAST getLastChild();
090
091    /**
092     * Checks if this branch of the parse tree contains a token of the provided type.
093     *
094     * @param type a TokenType
095     * @return true if and only if this branch (including this node)
096     *     contains a token of type {@code type}.
097     * @deprecated
098     *      Usage of this method is no longer accepted. We encourage
099     *      traversal of subtrees to be written per the needs of each check
100     *      to avoid unintended side effects.
101     * @noinspection DeprecatedIsStillUsed, RedundantSuppression
102     * @noinspectionreason DeprecatedIsStillUsed - Method used in unit testing
103     * @noinspectionreason RedundantSuppression - Inspections shows false positive for
104     *      redundant suppression, see
105     *      <a href="https://github.com/checkstyle/checkstyle/issues/12359">here</a>
106     *      for more details.
107     */
108    @Deprecated(since = "8.43")
109    boolean branchContains(int type);
110
111    /**
112     * Returns the previous sibling or null if no such sibling exists.
113     *
114     * @return the previous sibling or null if no such sibling exists.
115     */
116    DetailAST getPreviousSibling();
117
118    /**
119     * Returns the first child token that makes a specified type.
120     *
121     * @param type the token type to match
122     * @return the matching token, or null if no match
123     */
124    @Nullable
125    DetailAST findFirstToken(int type);
126
127    /**
128     * Get the next sibling in line after this one.
129     *
130     * @return the next sibling or null if none.
131     */
132    DetailAST getNextSibling();
133
134    /**
135     * Get the first child of this AST.
136     *
137     * @return the first child or null if none.
138     */
139    DetailAST getFirstChild();
140
141    /**
142     * Get number of children of this AST.
143     *
144     * @return the number of children.
145     * @deprecated This method will be removed in a future release.
146     *             Use {@link #getChildCount()} instead.
147     */
148    @Deprecated(since = "8.30")
149    int getNumberOfChildren();
150
151    /**
152     * Returns whether this AST has any children.
153     *
154     * @return {@code true} if this AST has any children.
155     */
156    boolean hasChildren();
157
158}