    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.List;
    020    import java.util.Set;
    021
    022    import org.apache.commons.lang3.tuple.Pair;
    023
    024    /**
    025     * Allows the storage and retrieval of contextual information based on label-value
    026     * pairs for exceptions.
    027     * <p>
    028     * Implementations are expected to manage the pairs in a list-style collection
    029     * that keeps the pairs in the sequence of their addition.
    030     * </p>
    031     *
    032     * @see ContextedException
    033     * @see ContextedRuntimeException
    034     * @since 3.0
    035     */
    036    public interface ExceptionContext {
    037
    038        /**
    039         * Adds a contextual label-value pair into this context.
    040         * <p>
    041         * The pair will be added to the context, independently of an already
    042         * existing pair with the same label.
    043         * </p>
    044         *
    045         * @param label  the label of the item to add, {@code null} not recommended
    046         * @param value  the value of item to add, may be {@code null}
    047         * @return {@code this}, for method chaining, not {@code null}
    048         */
    049        public ExceptionContext addContextValue(String label, Object value);
    050
    051        /**
    052         * Sets a contextual label-value pair into this context.
    053         * <p>
    054         * The pair will be added normally, but any existing label-value pair with
    055         * the same label is removed from the context.
    056         * </p>
    057         *
    058         * @param label  the label of the item to add, {@code null} not recommended
    059         * @param value  the value of item to add, may be {@code null}
    060         * @return {@code this}, for method chaining, not {@code null}
    061         */
    062        public ExceptionContext setContextValue(String label, Object value);
    063
    064        /**
    065         * Retrieves all the contextual data values associated with the label.
    066         *
    067         * @param label  the label to get the contextual values for, may be {@code null}
    068         * @return the contextual values associated with the label, never {@code null}
    069         */
    070        public List<Object> getContextValues(String label);
    071
    072        /**
    073         * Retrieves the first available contextual data value associated with the label.
    074         *
    075         * @param label  the label to get the contextual value for, may be {@code null}
    076         * @return the first contextual value associated with the label, may be {@code null}
    077         */
    078        public Object getFirstContextValue(String label);
    079
    080        /**
    081         * Retrieves the full set of labels defined in the contextual data.
    082         *
    083         * @return the set of labels, not {@code null}
    084         */
    085        public Set<String> getContextLabels();
    086
    087        /**
    088         * Retrieves the full list of label-value pairs defined in the contextual data.
    089         *
    090         * @return the list of pairs, not {@code null}
    091         */
    092        public List<Pair<String, Object>> getContextEntries();
    093
    094        /**
    095         * Gets the contextualized error message based on a base message.
    096         * This will add the context label-value pairs to the message.
    097         *
    098         * @param baseMessage  the base exception message <b>without</b> context information appended
    099         * @return the exception message <b>with</b> context information appended, not {@code null}
    100         */
    101        public String getFormattedExceptionMessage(String baseMessage);
    102
    103    }