src/jdk.compiler/share/classes/com/sun/source/util/DocTrees.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package com.sun.source.util;

import java.io.IOException;
import java.text.BreakIterator;
import java.util.List;

import javax.annotation.processing.ProcessingEnvironment;
import javax.lang.model.element.Element;
import javax.lang.model.element.PackageElement;
import javax.lang.model.type.TypeMirror;
import javax.lang.model.util.Elements.DocCommentKind;
import javax.tools.Diagnostic;
import javax.tools.FileObject;
import javax.tools.JavaCompiler.CompilationTask;

import com.sun.source.doctree.DocCommentTree;
import com.sun.source.doctree.DocTree;
import com.sun.source.doctree.EntityTree;
import com.sun.source.tree.CompilationUnitTree;

/**
 * Provides access to syntax trees for doc comments.
 *
 * @since 1.8
 */
public abstract class DocTrees extends Trees {
    /**
     * Constructor for subclasses to call.
     */
    public DocTrees() {}

    /**
     * Returns a DocTrees object for a given CompilationTask.
     * @param task the compilation task for which to get the Trees object
     * @return the DocTrees object
     * @throws IllegalArgumentException if the task does not support the Trees API.
     */
    public static DocTrees instance(CompilationTask task) {
        return (DocTrees) Trees.instance(task);
    }

    /**
     * Returns a DocTrees object for a given ProcessingEnvironment.
     * @param env the processing environment for which to get the Trees object
     * @return the DocTrees object
     * @throws IllegalArgumentException if the env does not support the Trees API.
     */
    public static DocTrees instance(ProcessingEnvironment env) {
        if (!env.getClass().getName().equals("com.sun.tools.javac.processing.JavacProcessingEnvironment"))
            throw new IllegalArgumentException();
        return (DocTrees) getJavacTrees(ProcessingEnvironment.class, env);
    }

    /**
     * Returns the break iterator used to compute the first sentence of
     * documentation comments.
     * Returns {@code null} if none has been specified.
     * @return the break iterator
     *
     * @since 9
     */
    public abstract BreakIterator getBreakIterator();

    /**
     * {@return the style of the documentation comment associated with a tree node}
     *
     * @param path the path for the tree node
     *
     * @see Trees#getPath(Element)
     * @since 23
     */
    public abstract DocCommentKind getDocCommentKind(TreePath path);

    /**
     * Returns the doc comment tree, if any, for the Tree node identified by a given TreePath.
     * Returns {@code null} if no doc comment was found.
     *
     * @implNote The default implementation of this method returns the same
     * {@code DocCommentTree} instance for repeated invocations
     * with the same argument.
     *
     * @param path the path for the tree node
     * @return the doc comment tree
     */
    public abstract DocCommentTree getDocCommentTree(TreePath path);

    /**
     * Returns the doc comment tree of the given element.
     * Returns {@code null} if no doc comment was found.
     *
     * @implNote The default implementation of this method returns the same
     * {@code DocCommentTree} instance for repeated invocations
     * with the same argument.
     *
     * @param e an element whose documentation is required
     * @return the doc comment tree
     *
     * @since 9
     */
    public abstract DocCommentTree getDocCommentTree(Element e);

    /**
     * Returns the doc comment tree of the given file, which must
     * be of one of the supported file types.
     *
     * <p>The supported file types are:
     * <ul>
     * <li>HTML files, identified by a file name ending in {@code .html},
     * <li>Markdown files, identified by a file name ending in {@code .md}.
     * </ul>
     * Future releases may support additional file types.
     *
     * @implNote The default implementation of this method returns a
     * new {@code DocCommentTree} instance for each invocation.
     *
     * @param fileObject the content container
     * @return the doc comment tree
     * @throws IllegalArgumentException if the file type is not supported
     *
     * @since 9
     */
    public abstract DocCommentTree getDocCommentTree(FileObject fileObject);

    /**
     * Returns the doc comment tree of the given file, which must
     * be of one of the supported file types, and whose path is
     * specified relative to the given element.
     *
     * <p>The supported file types are:
     * <ul>
     * <li>HTML files, identified by a file name ending in {@code .html},
     * <li>Markdown files, identified by a file name ending in {@code .md}.
     * </ul>
     * Future releases may support additional file types.
     *
     * @implNote The default implementation of this method returns a
     * new {@code DocCommentTree} instance for each invocation.
     *
     * @param e an element whose path is used as a reference
     * @param relativePath the relative path from the Element
     * @return the doc comment tree
     * @throws IOException if an exception occurs
     * @throws IllegalArgumentException if the file type is not supported
     *
     * @since 9
     */
    public abstract DocCommentTree getDocCommentTree(Element e, String relativePath) throws IOException;

    /**
     * Returns a doc tree path containing the doc comment tree of the given file,
     * which must be of one of the supported file types.
     *
     * Supported file types are HTML files and Markdown files.
     * Future releases may support additional file types.
     *
     * Any references to source code elements contained in {@code @see} and
     * {@code {@link}} tags in the doc comment tree will be evaluated in the
     * context of the given package element.
     * Returns {@code null} if no doc comment was found.
     *
     * @param fileObject a file object encapsulating the HTML content
     * @param packageElement a package element to associate with the given file object
     * representing a legacy package.html, null otherwise
     * @return a doc tree path containing the doc comment parsed from the given file
     * @throws IllegalArgumentException if the file type is not supported
     *
     * @since 9
     */
    public abstract DocTreePath getDocTreePath(FileObject fileObject, PackageElement packageElement);

    /**
     * Returns the language model element referred to by the leaf node of the given
     * {@link DocTreePath}, or {@code null} if unknown.
     * @param path the path for the tree node
     * @return the element
     */
    public abstract Element getElement(DocTreePath path);

    /**
     * Returns the language model type referred to by the leaf node of the given
     * {@link DocTreePath}, or {@code null} if unknown. This method usually
     * returns the same value as {@code getElement(path).asType()} for a
     * {@code path} argument for which {@link #getElement(DocTreePath)} returns
     * a non-null value, but may return a type that includes additional
     * information, such as a parameterized generic type instead of a raw type.
     *
     * @param path the path for the tree node
     * @return the referenced type, or null
     *
     * @since 15
     */
    public abstract TypeMirror getType(DocTreePath path);

    /**
     * Returns the list of {@link DocTree} representing the first sentence of
     * a comment.
     *
     * @param list the DocTree list to interrogate
     * @return the first sentence
     *
     * @since 9
     */
    public abstract List<DocTree> getFirstSentence(List<? extends DocTree> list);

    /**
     * Returns a utility object for accessing the source positions
     * of documentation tree nodes.
     * @return the utility object
     */
    public abstract DocSourcePositions getSourcePositions();

    /**
     * Prints a message of the specified kind at the location of the
     * tree within the provided compilation unit.
     *
     * @param kind the kind of message
     * @param msg  the message, or an empty string if none
     * @param t    the tree to use as a position hint
     * @param c    the doc comment tree to use as a position hint
     * @param root the compilation unit that contains tree
     */
    public abstract void printMessage(Diagnostic.Kind kind, CharSequence msg,
            DocTree t, DocCommentTree c, CompilationUnitTree root);

    /**
     * Sets the break iterator to compute the first sentence of
     * documentation comments.
     * @param breakIterator a break iterator or {@code null} to specify the default
     *                      sentence breaker
     *
     * @since 9
     */
    public abstract void setBreakIterator(BreakIterator breakIterator);

    /**
     * Returns a utility object for creating {@code DocTree} objects.
     * @return  a utility object for creating {@code DocTree} objects
     *
     * @since 9
     */
    public abstract DocTreeFactory getDocTreeFactory();

    /**
     * Returns a string containing the characters for the entity in a given entity tree,
     * or {@code null} if the tree does not represent a valid series of characters.
     *
     * <p>The interpretation of entities is based on section
     * <a href="https://www.w3.org/TR/html52/syntax.html#character-references">8.1.4. Character references</a>
     * in the HTML 5.2 specification.</p>
     *
     * @param tree the tree containing the entity
     * @return a string containing the characters
     * @spec https://www.w3.org/TR/html52 HTML Standard
     *
     * @since 16
     */
    public abstract String getCharacters(EntityTree tree);
}