    001/**
    002 * Copyright (c) 2004-2011 QOS.ch
    003 * All rights reserved.
    004 *
    005 * Permission is hereby granted, free  of charge, to any person obtaining
    006 * a  copy  of this  software  and  associated  documentation files  (the
    007 * "Software"), to  deal in  the Software without  restriction, including
    008 * without limitation  the rights to  use, copy, modify,  merge, publish,
    009 * distribute,  sublicense, and/or sell  copies of  the Software,  and to
    010 * permit persons to whom the Software  is furnished to do so, subject to
    011 * the following conditions:
    012 *
    013 * The  above  copyright  notice  and  this permission  notice  shall  be
    014 * included in all copies or substantial portions of the Software.
    015 *
    016 * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
    017 * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
    018 * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
    019 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
    020 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
    021 * OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
    022 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
    023 *
    024 */
    025package org.slf4j;
    026
    027import java.io.Serializable;
    028import java.util.Iterator;
    029
    030/**
    031 * Markers are named objects used to enrich log statements. Conforming logging
    032 * system Implementations of SLF4J determine how information conveyed by markers
    033 * are used, if at all. In particular, many conforming logging systems ignore
    034 * marker data.
    035 *
    036 * <p>
    037 * Markers can contain references to other markers, which in turn may contain
    038 * references of their own.
    039 *
    040 * @author Ceki G&uuml;lc&uuml;
    041 */
    042public interface Marker extends Serializable {
    043
    044    /**
    045     * This constant represents any marker, including a null marker.
    046     */
    047    public final String ANY_MARKER = "*";
    048
    049    /**
    050     * This constant represents any non-null marker.
    051     */
    052    public final String ANY_NON_NULL_MARKER = "+";
    053
    054    /**
    055     * Get the name of this Marker.
    056     *
    057     * @return name of marker
    058     */
    059    public String getName();
    060
    061    /**
    062     * Add a reference to another Marker.
    063     *
    064     * @param reference
    065     *                a reference to another marker
    066     * @throws IllegalArgumentException
    067     *                 if 'reference' is null
    068     */
    069    public void add(Marker reference);
    070
    071    /**
    072     * Remove a marker reference.
    073     *
    074     * @param reference
    075     *                the marker reference to remove
    076     * @return true if reference could be found and removed, false otherwise.
    077     */
    078    public boolean remove(Marker reference);
    079
    080    /**
    081     * @deprecated Replaced by {@link #hasReferences()}.
    082     */
    083    public boolean hasChildren();
    084
    085    /**
    086     * Does this marker have any references?
    087     *
    088     * @return true if this marker has one or more references, false otherwise.
    089     */
    090    public boolean hasReferences();
    091
    092    /**
    093     * Returns an Iterator which can be used to iterate over the references of this
    094     * marker. An empty iterator is returned when this marker has no references.
    095     *
    096     * @return Iterator over the references of this marker
    097     */
    098    public Iterator<Marker> iterator();
    099
    100    /**
    101     * Does this marker contain a reference to the 'other' marker? Marker A is defined
    102     * to contain marker B, if A == B or if B is referenced by A, or if B is referenced
    103     * by any one of A's references (recursively).
    104     *
    105     * @param other
    106     *                The marker to test for inclusion.
    107     * @throws IllegalArgumentException
    108     *                 if 'other' is null
    109     * @return Whether this marker contains the other marker.
    110     */
    111    public boolean contains(Marker other);
    112
    113    /**
    114     * Does this marker contain the marker named 'name'?
    115     *
    116     * If 'name' is null the returned value is always false.
    117     *
    118     * @param name The marker name to test for inclusion.
    119     * @return Whether this marker contains the other marker.
    120     */
    121    public boolean contains(String name);
    122
    123    /**
    124     * Markers are considered equal if they have the same name.
    125     *
    126     * @param o
    127     * @return true, if this.name equals o.name
    128     *
    129     * @since 1.5.1
    130     */
    131    public boolean equals(Object o);
    132
    133    /**
    134     * Compute the hash code based on the name of this marker.
    135     * Note that markers are considered equal if they have the same name.
    136     *
    137     * @return the computed hashCode
    138     * @since 1.5.1
    139     */
    140    public int hashCode();
    141
    142}