    001    /*
    002     * Licensed to the Apache Software Foundation (ASF) under one or more
    003     * contributor license agreements.  See the NOTICE file distributed with
    004     * this work for additional information regarding copyright ownership.
    005     * The ASF licenses this file to You under the Apache License, Version 2.0
    006     * (the "License"); you may not use this file except in compliance with
    007     * the License.  You may obtain a copy of the License at
    008     *
    009     *      http://www.apache.org/licenses/LICENSE-2.0
    010     *
    011     * Unless required by applicable law or agreed to in writing, software
    012     * distributed under the License is distributed on an "AS IS" BASIS,
    013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014     * See the License for the specific language governing permissions and
    015     * limitations under the License.
    016     */
    017    package org.apache.commons.lang3.exception;
    018
    019    import java.util.Set;
    020
    021    /**
    022     * Allows the storage and retrieval of contextual information based on label-value
    023     * pairs for exceptions.
    024     *
    025     * @see ContextedException
    026     * @see ContextedRuntimeException
    027     * @author Apache Software Foundation
    028     * @author D. Ashmore
    029     * @since 3.0
    030     */
    031    public interface ExceptionContext {
    032
    033        /**
    034         * Adds a contextual label-value pair into this context.
    035         * <p>
    036         * This label-value pair provides information useful for debugging. If the
    037         * provided label already exists, it depends on the implementation what
    038         * happens with the new value.
    039         * </p>
    040         *
    041         * @param label  the label of the item to add, null not recommended
    042         * @param value  the value of item to add, may be null
    043         * @return context itself to allow method chaining
    044         */
    045        public ExceptionContext addValue(String label, Object value);
    046
    047        /**
    048         * Replaces a contextual label-value pair of this context.
    049         * <p>
    050         * This label-value pair provides information useful for debugging. If the
    051         * label does not exist yet, it depends on the implementation what happens
    052         * with the provided value.
    053         * </p>
    054         *
    055         * @param label  the label of the item to add, null not recommended
    056         * @param value  the value of item to add, may be null
    057         * @return context itself to allow method chaining
    058         */
    059        public ExceptionContext replaceValue(String label, Object value);
    060
    061        /**
    062         * Retrieves a contextual data value associated with the label.
    063         *
    064         * @param label  the label to get the contextual value for, may be null
    065         * @return the contextual value associated with the label, may be null
    066         */
    067        public Object getValue(String label);
    068
    069        /**
    070         * Retrieves the labels defined in the contextual data.
    071         *
    072         * @return the set of labels, never null
    073         */
    074        public Set<String> getLabelSet();
    075
    076        /**
    077         * Implementors provide the given base message with context label/value item
    078         * information appended.
    079         *
    080         * @param baseMessage  the base exception message <b>without</b> context information appended
    081         * @return the exception message <b>with</b> context information appended, never null
    082         */
    083        public String getFormattedExceptionMessage(String baseMessage);
    084
    085    }