org.eclipse.jdt.core.IAccessRule.java Source code

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/*******************************************************************************
 * Copyright (c) 2000, 2013 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.core;

import org.eclipse.core.runtime.IPath;

/**
 * Describes an access rule to source and class files on a classpath entry.
 * An access rule is composed of a file pattern and a kind (accessible,
 * non accessible, or discouraged).
 * <p>
 * On a given classpath entry, the access rules are considered in the order given
 * when the entry was created. When a source or class file matches an access
 * rule's pattern, the access rule's kind defines whether the file is considered
 * accessible, non-accessible, or whether its access is discouraged. If the source or class
 * file doesn't match any access rule, it is considered accessible. A source or class
 * file that is not accessible or discouraged can still be referred to, but it is tagged as being not
 * accessible - the Java builder will create a problem marker, for example.
 * The severity of the marker created from a non-accessible rule is controlled through
 * the {@link JavaCore#COMPILER_PB_FORBIDDEN_REFERENCE} compiler option.
 * The severity of the marker created from a discouraged rule is controlled through
 * the {@link JavaCore#COMPILER_PB_DISCOURAGED_REFERENCE} compiler option.
 * Note this is different from inclusion and exclusion patterns on source classpath entries,
 * where a source file that is excluded is not even compiled.
 * </p>
 * <p>
 * Files patterns look like relative file paths with wildcards and are interpreted relative
 * to each entry's path.
 * File patterns are case-sensitive and they can contain '**', '*' or '?' wildcards (see
 * {@link IClasspathEntry#getExclusionPatterns()} for the full description
 * of their syntax and semantics).
 * Note that file patterns must not include the file extension.
 * <code>com/xyz/tests/MyClass</code> is a valid file pattern, whereas
 * <code>com/xyz/tests/MyClass.class</code> is not valid.
 * </p>
 * <p>
 * For example, if a classpath entry path is <code>/Project/someLib.jar</code>,
 * there are no accessible rules, and there is one non-accessible rule with pattern
 * <code>com/xyz/tests/&#42;&#42;</code>, then class files
 * like <code>/Project/someLib.jar/com/xyz/Foo.class</code>
 * and <code>/Project/someLib.jar/com/xyz/utils/Bar.class</code> would be accessible,
 * whereas <code>/Project/someLib.jar/com/xyz/tests/T1.class</code>
 * and <code>/Project/someLib.jar/com/xyz/tests/quick/T2.class</code> would not be
 * accessible.
 * </p>
 *
 * @since 3.1
 * 
 * @see JavaCore#newAccessRule(IPath, int)
 * @see IClasspathEntry#getExclusionPatterns()
 * 
 * @noimplement This interface is not intended to be implemented by clients.
 */
public interface IAccessRule {

    /**
     * Constant indicating that files matching the rule's pattern are accessible.
     */
    int K_ACCESSIBLE = 0;

    /**
     * Constant indicating that files matching the rule's pattern are non-accessible.
     */
    int K_NON_ACCESSIBLE = 1;

    /**
     * Constant indicating that access to the files matching the rule's pattern is discouraged.
     */
    int K_DISCOURAGED = 2;

    /**
     * <p>Flag indicating that whether a type matching this rule should be ignored iff a type with
     * the same qualified name can be found on a later classpath entry with a better
     * accessibility.</p>
     * <p>E.g. if a type p.X matches a rule K_NON_ACCESSIBLE | IGNORE_IF_BETTER
     * on a library entry 'lib1' and another type p.X also matches a rule
     * K_DISCOURAGED on library entry 'lib2' ('lib2' being after 'lib1' on the
     * classpath), then p.X from 'lib2' will be used and reported as
     * discouraged.</p>
     *
     * @since 3.2
     */
    int IGNORE_IF_BETTER = 0x100;

    /**
     * Returns the file pattern for this access rule.
     *
     * @return the file pattern for this access rule
     *
     * @see IClasspathEntry#getExclusionPatterns()
     */
    IPath getPattern();

    /**
     * Returns the kind of this access rule (one of {@link #K_ACCESSIBLE}, {@link #K_NON_ACCESSIBLE}
     * or {@link #K_DISCOURAGED}).
     *
     * @return the kind of this access rule
     */
    int getKind();

    /**
     * <p>Returns whether a type matching this rule should be ignored iff a type with
     * the same qualified name can be found on a later classpath entry with a better
     * accessibility.</p>
     * <p>E.g. if a type p.X matches a rule K_NON_ACCESSIBLE | IGNORE_IF_BETTER
     * on a library entry 'lib1' and another type p.X also matches a rule
     * K_DISCOURAGED on library entry 'lib2' ('lib2' being after 'lib1' on the
     * classpath), then p.X from 'lib2' will be used and reported as
     * discouraged.</p>
     *
     * @return whether a type matching this rule should be ignored iff a type
     *              with the same qualified name can be found on a later classpath
     *              entry with a better accessibility
     * @since 3.2
     */
    boolean ignoreIfBetter();

}