    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 */
    017package org.apache.commons.lang3.exception;
    018
    019import java.io.Serializable;
    020import java.util.ArrayList;
    021import java.util.HashSet;
    022import java.util.List;
    023import java.util.Set;
    024
    025import org.apache.commons.lang3.StringUtils;
    026import org.apache.commons.lang3.tuple.ImmutablePair;
    027import org.apache.commons.lang3.tuple.Pair;
    028
    029/**
    030 * Default implementation of the context storing the label-value pairs for contexted exceptions.
    031 * <p>
    032 * This implementation is serializable, however this is dependent on the values that
    033 * are added also being serializable.
    034 * </p>
    035 *
    036 * @see ContextedException
    037 * @see ContextedRuntimeException
    038 * @since 3.0
    039 */
    040public class DefaultExceptionContext implements ExceptionContext, Serializable {
    041
    042    /** The serialization version. */
    043    private static final long serialVersionUID = 20110706L;
    044
    045    /** The list storing the label-data pairs. */
    046    private final List<Pair<String, Object>> contextValues = new ArrayList<>();
    047
    048    /**
    049     * {@inheritDoc}
    050     */
    051    @Override
    052    public DefaultExceptionContext addContextValue(final String label, final Object value) {
    053        contextValues.add(new ImmutablePair<>(label, value));
    054        return this;
    055    }
    056
    057    /**
    058     * {@inheritDoc}
    059     */
    060    @Override
    061    public DefaultExceptionContext setContextValue(final String label, final Object value) {
    062        contextValues.removeIf(p -> StringUtils.equals(label, p.getKey()));
    063        addContextValue(label, value);
    064        return this;
    065    }
    066
    067    /**
    068     * {@inheritDoc}
    069     */
    070    @Override
    071    public List<Object> getContextValues(final String label) {
    072        final List<Object> values = new ArrayList<>();
    073        for (final Pair<String, Object> pair : contextValues) {
    074            if (StringUtils.equals(label, pair.getKey())) {
    075                values.add(pair.getValue());
    076            }
    077        }
    078        return values;
    079    }
    080
    081    /**
    082     * {@inheritDoc}
    083     */
    084    @Override
    085    public Object getFirstContextValue(final String label) {
    086        for (final Pair<String, Object> pair : contextValues) {
    087            if (StringUtils.equals(label, pair.getKey())) {
    088                return pair.getValue();
    089            }
    090        }
    091        return null;
    092    }
    093
    094    /**
    095     * {@inheritDoc}
    096     */
    097    @Override
    098    public Set<String> getContextLabels() {
    099        final Set<String> labels = new HashSet<>();
    100        for (final Pair<String, Object> pair : contextValues) {
    101            labels.add(pair.getKey());
    102        }
    103        return labels;
    104    }
    105
    106    /**
    107     * {@inheritDoc}
    108     */
    109    @Override
    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    @Override
    121    public String getFormattedExceptionMessage(final String baseMessage) {
    122        final StringBuilder buffer = new StringBuilder(256);
    123        if (baseMessage != null) {
    124            buffer.append(baseMessage);
    125        }
    126
    127        if (!contextValues.isEmpty()) {
    128            if (buffer.length() > 0) {
    129                buffer.append('\n');
    130            }
    131            buffer.append("Exception Context:\n");
    132
    133            int i = 0;
    134            for (final Pair<String, Object> pair : contextValues) {
    135                buffer.append("\t[");
    136                buffer.append(++i);
    137                buffer.append(':');
    138                buffer.append(pair.getKey());
    139                buffer.append("=");
    140                final Object value = pair.getValue();
    141                if (value == null) {
    142                    buffer.append("null");
    143                } else {
    144                    String valueStr;
    145                    try {
    146                        valueStr = value.toString();
    147                    } catch (final Exception e) {
    148                        valueStr = "Exception thrown on toString(): " + ExceptionUtils.getStackTrace(e);
    149                    }
    150                    buffer.append(valueStr);
    151                }
    152                buffer.append("]\n");
    153            }
    154            buffer.append("---------------------------------");
    155        }
    156        return buffer.toString();
    157    }
    158
    159}