001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2021 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.checks.indentation;
021
022import java.util.BitSet;
023
024/**
025 * Encapsulates representation of notion of expected indentation levels.
026 * Provide a way to have multiple acceptable levels.
027 * This class is immutable.
028 */
029public class IndentLevel {
030
031    /** Set of acceptable indentation levels. */
032    private final BitSet levels = new BitSet();
033
034    /**
035     * Creates new instance with one acceptable indentation level.
036     *
037     * @param indent acceptable indentation level.
038     */
039    public IndentLevel(int indent) {
040        levels.set(indent);
041    }
042
043    /**
044     * Creates new instance for nested structure.
045     *
046     * @param base parent's level
047     * @param offsets offsets from parent's level.
048     */
049    public IndentLevel(IndentLevel base, int... offsets) {
050        final BitSet src = base.levels;
051        for (int i = src.nextSetBit(0); i >= 0; i = src.nextSetBit(i + 1)) {
052            for (int offset : offsets) {
053                levels.set(i + offset);
054            }
055        }
056    }
057
058    /**
059     * Creates new instance with no acceptable indentation level.
060     * This is only used internally to combine multiple levels.
061     */
062    private IndentLevel() {
063    }
064
065    /**
066     * Checks whether we have more than one level.
067     *
068     * @return whether we have more than one level.
069     */
070    public final boolean isMultiLevel() {
071        return levels.cardinality() > 1;
072    }
073
074    /**
075     * Checks if given indentation is acceptable.
076     *
077     * @param indent indentation to check.
078     * @return true if given indentation is acceptable,
079     *         false otherwise.
080     */
081    public boolean isAcceptable(int indent) {
082        return levels.get(indent);
083    }
084
085    /**
086     * Returns true if indent less than minimal of
087     * acceptable indentation levels, false otherwise.
088     *
089     * @param indent indentation to check.
090     * @return true if {@code indent} less than minimal of
091     *         acceptable indentation levels, false otherwise.
092     */
093    public boolean isGreaterThan(int indent) {
094        return levels.nextSetBit(0) > indent;
095    }
096
097    /**
098     * Adds one or more acceptable indentation level.
099     *
100     * @param base class to add new indentations to.
101     * @param additions new acceptable indentation.
102     * @return New acceptable indentation level instance.
103     */
104    public static IndentLevel addAcceptable(IndentLevel base, int... additions) {
105        final IndentLevel result = new IndentLevel();
106        result.levels.or(base.levels);
107        for (int addition : additions) {
108            result.levels.set(addition);
109        }
110        return result;
111    }
112
113    /**
114     * Combines 2 acceptable indentation level classes.
115     *
116     * @param base class to add new indentations to.
117     * @param addition new acceptable indentation.
118     * @return New acceptable indentation level instance.
119     */
120    public static IndentLevel addAcceptable(IndentLevel base, IndentLevel addition) {
121        final IndentLevel result = new IndentLevel();
122        result.levels.or(base.levels);
123        result.levels.or(addition.levels);
124        return result;
125    }
126
127    /**
128     * Returns first indentation level.
129     *
130     * @return indentation level.
131     */
132    public int getFirstIndentLevel() {
133        return levels.nextSetBit(0);
134    }
135
136    /**
137     * Returns last indentation level.
138     *
139     * @return indentation level.
140     */
141    public int getLastIndentLevel() {
142        return levels.length() - 1;
143    }
144
145    @Override
146    public String toString() {
147        final String result;
148        if (levels.cardinality() == 1) {
149            result = String.valueOf(levels.nextSetBit(0));
150        }
151        else {
152            final StringBuilder sb = new StringBuilder(50);
153            for (int i = levels.nextSetBit(0); i >= 0;
154                 i = levels.nextSetBit(i + 1)) {
155                if (sb.length() > 0) {
156                    sb.append(", ");
157                }
158                sb.append(i);
159            }
160            result = sb.toString();
161        }
162        return result;
163    }
164
165}