001package org.jsoup.select;
002
003import org.jsoup.helper.Validate;
004import org.jsoup.nodes.Element;
005import org.jspecify.annotations.Nullable;
006
007import java.util.Collection;
008import java.util.IdentityHashMap;
009
010/**
011 * CSS-like element selector, that finds elements matching a query.
012 *
013 * <h2>Selector syntax</h2>
014 * <p>
015 * A selector is a chain of simple selectors, separated by combinators. Selectors are <b>case insensitive</b> (including against
016 * elements, attributes, and attribute values).
017 * </p>
018 * <p>
019 * The universal selector {@code *} is implicit when no element selector is supplied (i.e. {@code .header} and {@code *.header}
020 * are equivalent).
021 * </p>
022 * <style>table.syntax tr td {vertical-align: top; padding-right: 2em; padding-top:0.5em; padding-bottom:0.5em; } table.syntax tr:hover{background-color: #eee;} table.syntax {border-spacing: 0px 0px;}</style>
023 * <table summary="" class="syntax"><colgroup><col span="1" style="width: 20%;"><col span="1" style="width: 40%;"><col span="1" style="width: 40%;"></colgroup>
024 * <tr><th align="left">Pattern</th><th align="left">Matches</th><th align="left">Example</th></tr>
025 * <tr><td><code>*</code></td><td>any element</td><td><code>*</code></td></tr>
026 * <tr><td><code>tag</code></td><td>elements with the given tag name</td><td><code>div</code></td></tr>
027 * <tr><td><code>*|E</code></td><td>elements of type E in any namespace (including non-namespaced)</td><td><code>*|name</code> finds <code>&lt;fb:name&gt;</code> and <code>&lt;name&gt;</code> elements</td></tr>
028 * <tr><td><code>ns|E</code></td><td>elements of type E in the namespace <i>ns</i></td><td><code>fb|name</code> finds <code>&lt;fb:name&gt;</code> elements</td></tr>
029 * <tr><td><code>#id</code></td><td>elements with attribute ID of "id"</td><td><code>div#wrap</code>, <code>#logo</code></td></tr>
030 * <tr><td><code>.class</code></td><td>elements with a class name of "class"</td><td><code>div.left</code>, <code>.result</code></td></tr>
031 * <tr><td><code>[attr]</code></td><td>elements with an attribute named "attr" (with any value)</td><td><code>a[href]</code>, <code>[title]</code></td></tr>
032 * <tr><td><code>[^attrPrefix]</code></td><td>elements with an attribute name starting with "attrPrefix". Use to find elements with HTML5 datasets</td><td><code>[^data-]</code>, <code>div[^data-]</code></td></tr>
033 * <tr><td><code>[attr=val]</code></td><td>elements with an attribute named "attr", and value equal to "val"</td><td><code>img[width=500]</code>, <code>a[rel=nofollow]</code></td></tr>
034 * <tr><td><code>[attr=&quot;val&quot;]</code></td><td>elements with an attribute named "attr", and value equal to "val"</td><td><code>span[hello="Cleveland"][goodbye="Columbus"]</code>, <code>a[rel=&quot;nofollow&quot;]</code></td></tr>
035 * <tr><td><code>[attr^=valPrefix]</code></td><td>elements with an attribute named "attr", and value starting with "valPrefix"</td><td><code>a[href^=http:]</code></td></tr>
036 * <tr><td><code>[attr$=valSuffix]</code></td><td>elements with an attribute named "attr", and value ending with "valSuffix"</td><td><code>img[src$=.png]</code></td></tr>
037 * <tr><td><code>[attr*=valContaining]</code></td><td>elements with an attribute named "attr", and value containing "valContaining"</td><td><code>a[href*=/search/]</code></td></tr>
038 * <tr><td><code>[attr~=<em>regex</em>]</code></td><td>elements with an attribute named "attr", and value matching the regular expression</td><td><code>img[src~=(?i)\\.(png|jpe?g)]</code></td></tr>
039 * <tr><td><code>[*]</code></td><td>elements with any attribute</td><td><code>p[*]</code> finds <code>p</code> elements that have at least one attribute; <code>p:not([*])</code> finds those with no attributes</td></tr>
040 * <tr><td></td><td>The above may be combined in any order</td><td><code>div.header[title]</code></td></tr>
041 * <tr><td colspan="3"><h3>Combinators</h3></td></tr>
042 * <tr><td><code>E F</code></td><td>an F element descended from an E element</td><td><code>div a</code>, <code>.logo h1</code></td></tr>
043 * <tr><td><code>E {@literal >} F</code></td><td>an F direct child of E</td><td><code>ol {@literal >} li</code></td></tr>
044 * <tr><td><code>E + F</code></td><td>an F element immediately preceded by sibling E</td><td><code>li + li</code>, <code>div.head + div</code></td></tr>
045 * <tr><td><code>E ~ F</code></td><td>an F element preceded by sibling E</td><td><code>h1 ~ p</code></td></tr>
046 * <tr><td><code>E, F, G</code></td><td>all matching elements E, F, or G</td><td><code>a[href], div, h3</code></td></tr>
047 * <tr><td colspan="3"><h3>Pseudo selectors</h3></td></tr>
048 * <tr><td><code>:lt(<em>n</em>)</code></td><td>elements whose sibling index is less than <em>n</em></td><td><code>td:lt(3)</code> finds the first 3 cells of each row</td></tr>
049 * <tr><td><code>:gt(<em>n</em>)</code></td><td>elements whose sibling index is greater than <em>n</em></td><td><code>td:gt(1)</code> finds cells after skipping the first two</td></tr>
050 * <tr><td><code>:eq(<em>n</em>)</code></td><td>elements whose sibling index is equal to <em>n</em></td><td><code>td:eq(0)</code> finds the first cell of each row</td></tr>
051 * <tr><td><code>:has(<em>selector</em>)</code></td><td>elements that contains at least one element matching the <em>selector</em></td><td><code>div:has(p)</code> finds <code>div</code>s that contain <code>p</code> elements.<br><code>div:has(&gt; a)</code> selects <code>div</code> elements that have at least one direct child <code>a</code> element.<br><code>section:has(h1, h2)</code> finds <code>section</code> elements that contain a <code>h1</code> or a <code>h2</code> element</td></tr>
052 * <tr><td><code>:is(<em>selector list</em>)</code></td><td>elements that match any of the selectors in the selector list</td><td><code>:is(h1, h2, h3, h4, h5, h6)</code> finds any heading element.<br><code>:is(section, article) > :is(h1, h2)</code> finds a <code>h1</code> or <code>h2</code> that is a direct child of a <code>section</code> or an <code>article</code></td></tr>
053 * <tr><td><code>:not(<em>selector</em>)</code></td><td>elements that do not match the <em>selector</em>. See also {@link Elements#not(String)}</td><td><code>div:not(.logo)</code> finds all divs that do not have the "logo" class.<p><code>div:not(:has(div))</code> finds divs that do not contain divs.</p></td></tr>
054 * <tr><td><code>:contains(<em>text</em>)</code></td><td>elements that contains the specified text. The search is case insensitive. The text may appear in the found element, or any of its descendants. The text is whitespace normalized. <p>To find content that includes parentheses, escape those with a {@code \}.</p></td><td><code>p:contains(jsoup)</code> finds p elements containing the text "jsoup".<p>{@code p:contains(hello \(there\) finds p elements containing the text "Hello (There)"}</p></td></tr>
055 * <tr><td><code>:containsOwn(<em>text</em>)</code></td><td>elements that directly contain the specified text. The search is case insensitive. The text must appear in the found element, not any of its descendants.</td><td><code>p:containsOwn(jsoup)</code> finds p elements with own text "jsoup".</td></tr>
056 * <tr><td><code>:containsData(<em>data</em>)</code></td><td>elements that contains the specified <em>data</em>. The contents of {@code script} and {@code style} elements, and {@code comment} nodes (etc) are considered data nodes, not text nodes. The search is case insensitive. The data may appear in the found element, or any of its descendants.</td><td><code>script:contains(jsoup)</code> finds script elements containing the data "jsoup".</td></tr>
057 * <tr><td><code>:containsWholeText(<em>text</em>)</code></td><td>elements that contains the specified <b>non-normalized</b> text. The search is case sensitive, and will match exactly against spaces and newlines found in the original input. The text may appear in the found element, or any of its descendants. <p>To find content that includes parentheses, escape those with a {@code \}.</p></td><td><code>p:containsWholeText(jsoup\nThe Java HTML Parser)</code> finds p elements containing the text <code>"jsoup\nThe Java HTML Parser"</code> (and not other variations of whitespace or casing, as <code>:contains()</code> would. Note that {@code br} elements are presented as a newline.</p></td></tr>
058 * <tr><td><code>:containsWholeOwnText(<em>text</em>)</code></td><td>elements that <b>directly</b> contain the specified <b>non-normalized</b> text. The search is case sensitive, and will match exactly against spaces and newlines found in the original input. The text may appear in the found element, but not in its descendants. <p>To find content that includes parentheses, escape those with a {@code \}.</p></td><td><code>p:containsWholeOwnText(jsoup\nThe Java HTML Parser)</code> finds p elements directly containing the text <code>"jsoup\nThe Java HTML Parser"</code> (and not other variations of whitespace or casing, as <code>:contains()</code> would. Note that {@code br} elements are presented as a newline.</p></td></tr>
059 * <tr><td><code>:matches(<em>regex</em>)</code></td><td>elements containing <b>whitespace normalized</b> text that matches the specified regular expression. The text may appear in the found element, or any of its descendants.</td><td><code>td:matches(\\d+)</code> finds table cells containing digits. <code>div:matches((?i)login)</code> finds divs containing the text, case insensitively.</td></tr>
060 * <tr><td><code>:matchesWholeText(<em>regex</em>)</code></td><td>elements containing <b>non-normalized</b> whole text that matches the specified regular expression. The text may appear in the found element, or any of its descendants.</td><td><code>td:matchesWholeText(\\s{2,})</code> finds table cells a run of at least two space characters.</td></tr>
061 * <tr><td><code>:matchesWholeOwnText(<em>regex</em>)</code></td><td>elements whose own <b>non-normalized</b> whole text matches the specified regular expression. The text must appear in the found element, not any of its descendants.</td><td><code>td:matchesWholeOwnText(\n\\d+)</code> finds table cells directly containing digits following a neewline.</td></tr>
062 * <tr><td></td><td>The above may be combined in any order and with other selectors</td><td><code>.light:contains(name):eq(0)</code></td></tr>
063 * <tr><td><code>:matchText</code></td><td>treats text nodes as elements, and so allows you to match against and select text nodes.<p><b>Note</b> that using this selector will modify the DOM, so you may want to {@code clone} your document before using.</td><td>{@code p:matchText:firstChild} with input {@code <p>One<br />Two</p>} will return one {@link org.jsoup.nodes.PseudoTextElement} with text "{@code One}".</td></tr>
064 * <tr><td colspan="3"><h3>Structural pseudo selectors</h3></td></tr>
065 * <tr><td><code>:root</code></td><td>The element that is the root of the document. In HTML, this is the <code>html</code> element</td><td><code>:root</code></td></tr>
066 * <tr><td><code>:nth-child(<em>a</em>n+<em>b</em>)</code></td><td><p>elements that have <code><em>a</em>n+<em>b</em>-1</code> siblings <b>before</b> it in the document tree, for any positive integer or zero value of <code>n</code>, and has a parent element. For values of <code>a</code> and <code>b</code> greater than zero, this effectively divides the element's children into groups of a elements (the last group taking the remainder), and selecting the <em>b</em>th element of each group. For example, this allows the selectors to address every other row in a table, and could be used to alternate the color of paragraph text in a cycle of four. The <code>a</code> and <code>b</code> values must be integers (positive, negative, or zero). The index of the first child of an element is 1.</p>
067 * Additionally, <code>:nth-child()</code> supports <code>odd</code> and <code>even</code> as arguments. <code>odd</code> is the same as <code>2n+1</code>, and <code>even</code> is the same as <code>2n</code>.</td><td><code>tr:nth-child(2n+1)</code> finds every odd row of a table. <code>:nth-child(10n-1)</code> the 9th, 19th, 29th, etc, element. <code>li:nth-child(5)</code> the 5h li</td></tr>
068 * <tr><td><code>:nth-last-child(<em>a</em>n+<em>b</em>)</code></td><td>elements that have <code><em>a</em>n+<em>b</em>-1</code> siblings <b>after</b> it in the document tree. Otherwise like <code>:nth-child()</code></td><td><code>tr:nth-last-child(-n+2)</code> the last two rows of a table</td></tr>
069 * <tr><td><code>:nth-of-type(<em>a</em>n+<em>b</em>)</code></td><td>pseudo-class notation represents an element that has <code><em>a</em>n+<em>b</em>-1</code> siblings with the same expanded element name <em>before</em> it in the document tree, for any zero or positive integer value of n, and has a parent element</td><td><code>img:nth-of-type(2n+1)</code></td></tr>
070 * <tr><td><code>:nth-last-of-type(<em>a</em>n+<em>b</em>)</code></td><td>pseudo-class notation represents an element that has <code><em>a</em>n+<em>b</em>-1</code> siblings with the same expanded element name <em>after</em> it in the document tree, for any zero or positive integer value of n, and has a parent element</td><td><code>img:nth-last-of-type(2n+1)</code></td></tr>
071 * <tr><td><code>:first-child</code></td><td>elements that are the first child of some other element.</td><td><code>div {@literal >} p:first-child</code></td></tr>
072 * <tr><td><code>:last-child</code></td><td>elements that are the last child of some other element.</td><td><code>ol {@literal >} li:last-child</code></td></tr>
073 * <tr><td><code>:first-of-type</code></td><td>elements that are the first sibling of its type in the list of children of its parent element</td><td><code>dl dt:first-of-type</code></td></tr>
074 * <tr><td><code>:last-of-type</code></td><td>elements that are the last sibling of its type in the list of children of its parent element</td><td><code>tr {@literal >} td:last-of-type</code></td></tr>
075 * <tr><td><code>:only-child</code></td><td>elements that have a parent element and whose parent element have no other element children</td><td></td></tr>
076 * <tr><td><code>:only-of-type</code></td><td> an element that has a parent element and whose parent element has no other element children with the same expanded element name</td><td></td></tr>
077 * <tr><td><code>:empty</code></td><td>elements that have no children at all</td><td></td></tr>
078 * </table>
079 *
080 * <p>A word on using regular expressions in these selectors: depending on the content of the regex, you will need to quote the pattern using <b><code>Pattern.quote("regex")</code></b> for it to parse correctly through both the selector parser and the regex parser. E.g. <code>String query = "div:matches(" + Pattern.quote(regex) + ");"</code>.</p>
081 * <p><b>Escaping special characters:</b> to match a tag, ID, or other selector that does not follow the regular CSS syntax, the query must be escaped with the <code>\</code> character. For example, to match by ID {@code <p id="i.d">}, use {@code document.select("#i\\.d")}.</p>
082 *
083 * @see Element#select(String css)
084 * @see Elements#select(String css)
085 * @see Element#selectXpath(String xpath)
086 */
087public class Selector {
088    // not instantiable
089    private Selector() {}
090
091    /**
092     * Find elements matching selector.
093     *
094     * @param query CSS selector
095     * @param root  root element to descend into
096     * @return matching elements, empty if none
097     * @throws Selector.SelectorParseException (unchecked) on an invalid CSS query.
098     */
099    public static Elements select(String query, Element root) {
100        Validate.notEmpty(query);
101        return select(QueryParser.parse(query), root);
102    }
103
104    /**
105     * Find elements matching selector.
106     *
107     * @param evaluator CSS selector
108     * @param root root element to descend into
109     * @return matching elements, empty if none
110     */
111    public static Elements select(Evaluator evaluator, Element root) {
112        Validate.notNull(evaluator);
113        Validate.notNull(root);
114        return Collector.collect(evaluator, root);
115    }
116
117    /**
118     * Find elements matching selector.
119     *
120     * @param query CSS selector
121     * @param roots root elements to descend into
122     * @return matching elements, empty if none
123     */
124    public static Elements select(String query, Iterable<Element> roots) {
125        Validate.notEmpty(query);
126        Validate.notNull(roots);
127        Evaluator evaluator = QueryParser.parse(query);
128        Elements elements = new Elements();
129        IdentityHashMap<Element, Boolean> seenElements = new IdentityHashMap<>();
130        // dedupe elements by identity, not equality
131
132        for (Element root : roots) {
133            final Elements found = select(evaluator, root);
134            for (Element el : found) {
135                if (seenElements.put(el, Boolean.TRUE) == null) {
136                    elements.add(el);
137                }
138            }
139        }
140        return elements;
141    }
142
143    // exclude set. package open so that Elements can implement .not() selector.
144    static Elements filterOut(Collection<Element> elements, Collection<Element> outs) {
145        Elements output = new Elements();
146        for (Element el : elements) {
147            boolean found = false;
148            for (Element out : outs) {
149                if (el.equals(out)) {
150                    found = true;
151                    break;
152                }
153            }
154            if (!found)
155                output.add(el);
156        }
157        return output;
158    }
159
160    /**
161     * Find the first element that matches the query.
162     * @param cssQuery CSS selector
163     * @param root root element to descend into
164     * @return the matching element, or <b>null</b> if none.
165     */
166    public static @Nullable Element selectFirst(String cssQuery, Element root) {
167        Validate.notEmpty(cssQuery);
168        return Collector.findFirst(QueryParser.parse(cssQuery), root);
169    }
170
171    public static class SelectorParseException extends IllegalStateException {
172        public SelectorParseException(String msg) {
173            super(msg);
174        }
175
176        public SelectorParseException(String msg, Object... msgArgs) {
177            super(String.format(msg, msgArgs));
178        }
179
180        public SelectorParseException(Throwable cause, String msg, Object... msgArgs) {
181            super(String.format(msg, msgArgs), cause);
182        }
183    }
184}