    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.io.Serializable;
    020    import java.util.ArrayList;
    021    import java.util.HashSet;
    022    import java.util.Iterator;
    023    import java.util.List;
    024    import java.util.Set;
    025
    026    import org.apache.commons.lang3.StringUtils;
    027    import org.apache.commons.lang3.tuple.ImmutablePair;
    028    import org.apache.commons.lang3.tuple.Pair;
    029
    030    /**
    031     * Default implementation of the context storing the label-value pairs for contexted exceptions.
    032     * <p>
    033     * This implementation is serializable, however this is dependent on the values that
    034     * are added also being serializable.
    035     * </p>
    036     *
    037     * @see ContextedException
    038     * @see ContextedRuntimeException
    039     * @since 3.0
    040     */
    041    public class DefaultExceptionContext implements ExceptionContext, Serializable {
    042
    043        /** The serialization version. */
    044        private static final long serialVersionUID = 20110706L;
    045
    046        /** The list storing the label-data pairs. */
    047        private final List<Pair<String, Object>> contextValues = new ArrayList<Pair<String,Object>>();
    048
    049        /**
    050         * {@inheritDoc}
    051         */
    052        public DefaultExceptionContext addContextValue(String label, Object value) {
    053            contextValues.add(new ImmutablePair<String, Object>(label, value));
    054            return this;
    055        }
    056
    057        /**
    058         * {@inheritDoc}
    059         */
    060        public DefaultExceptionContext setContextValue(String label, Object value) {
    061            for (final Iterator<Pair<String, Object>> iter = contextValues.iterator(); iter.hasNext();) {
    062                final Pair<String, Object> p = iter.next();
    063                if (StringUtils.equals(label, p.getKey())) {
    064                    iter.remove();
    065                }
    066            }
    067            addContextValue(label, value);
    068            return this;
    069        }
    070
    071        /**
    072         * {@inheritDoc}
    073         */
    074        public List<Object> getContextValues(String label) {
    075            final List<Object> values = new ArrayList<Object>();
    076            for (final Pair<String, Object> pair : contextValues) {
    077                if (StringUtils.equals(label, pair.getKey())) {
    078                    values.add(pair.getValue());
    079                }
    080            }
    081            return values;
    082        }
    083
    084        /**
    085         * {@inheritDoc}
    086         */
    087        public Object getFirstContextValue(String label) {
    088            for (final Pair<String, Object> pair : contextValues) {
    089                if (StringUtils.equals(label, pair.getKey())) {
    090                    return pair.getValue();
    091                }
    092            }
    093            return null;
    094        }
    095
    096        /**
    097         * {@inheritDoc}
    098         */
    099        public Set<String> getContextLabels() {
    100            final Set<String> labels = new HashSet<String>();
    101            for (final Pair<String, Object> pair : contextValues) {
    102                labels.add(pair.getKey());
    103            }
    104            return labels;
    105        }
    106
    107        /**
    108         * {@inheritDoc}
    109         */
    110        public List<Pair<String, Object>> getContextEntries() {
    111            return contextValues;
    112        }
    113
    114        /**
    115         * Builds the message containing the contextual information.
    116         *
    117         * @param baseMessage  the base exception message <b>without</b> context information appended
    118         * @return the exception message <b>with</b> context information appended, never null
    119         */
    120        public String getFormattedExceptionMessage(String baseMessage){
    121            StringBuilder buffer = new StringBuilder(256);
    122            if (baseMessage != null) {
    123                buffer.append(baseMessage);
    124            }
    125
    126            if (contextValues.size() > 0) {
    127                if (buffer.length() > 0) {
    128                    buffer.append('\n');
    129                }
    130                buffer.append("Exception Context:\n");
    131
    132                int i = 0;
    133                for (final Pair<String, Object> pair : contextValues) {
    134                    buffer.append("\t[");
    135                    buffer.append(++i);
    136                    buffer.append(':');
    137                    buffer.append(pair.getKey());
    138                    buffer.append("=");
    139                    final Object value = pair.getValue();
    140                    if (value == null) {
    141                        buffer.append("null");
    142                    } else {
    143                        String valueStr;
    144                        try {
    145                            valueStr = value.toString();
    146                        } catch (Exception e) {
    147                            valueStr = "Exception thrown on toString(): " + ExceptionUtils.getStackTrace(e);
    148                        }
    149                        buffer.append(valueStr);
    150                    }
    151                    buffer.append("]\n");
    152                }
    153                buffer.append("---------------------------------");
    154            }
    155            return buffer.toString();
    156        }
    157
    158    }