    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.Iterator;
    023import java.util.List;
    024import java.util.Set;
    025
    026import org.apache.commons.lang3.StringUtils;
    027import org.apache.commons.lang3.tuple.ImmutablePair;
    028import 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 */
    041public 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<>();
    048
    049    /**
    050     * {@inheritDoc}
    051     */
    052    @Override
    053    public DefaultExceptionContext addContextValue(final String label, final Object value) {
    054        contextValues.add(new ImmutablePair<>(label, value));
    055        return this;
    056    }
    057
    058    /**
    059     * {@inheritDoc}
    060     */
    061    @Override
    062    public DefaultExceptionContext setContextValue(final String label, final Object value) {
    063        for (final Iterator<Pair<String, Object>> iter = contextValues.iterator(); iter.hasNext();) {
    064            final Pair<String, Object> p = iter.next();
    065            if (StringUtils.equals(label, p.getKey())) {
    066                iter.remove();
    067            }
    068        }
    069        addContextValue(label, value);
    070        return this;
    071    }
    072
    073    /**
    074     * {@inheritDoc}
    075     */
    076    @Override
    077    public List<Object> getContextValues(final String label) {
    078        final List<Object> values = new ArrayList<>();
    079        for (final Pair<String, Object> pair : contextValues) {
    080            if (StringUtils.equals(label, pair.getKey())) {
    081                values.add(pair.getValue());
    082            }
    083        }
    084        return values;
    085    }
    086
    087    /**
    088     * {@inheritDoc}
    089     */
    090    @Override
    091    public Object getFirstContextValue(final String label) {
    092        for (final Pair<String, Object> pair : contextValues) {
    093            if (StringUtils.equals(label, pair.getKey())) {
    094                return pair.getValue();
    095            }
    096        }
    097        return null;
    098    }
    099
    100    /**
    101     * {@inheritDoc}
    102     */
    103    @Override
    104    public Set<String> getContextLabels() {
    105        final Set<String> labels = new HashSet<>();
    106        for (final Pair<String, Object> pair : contextValues) {
    107            labels.add(pair.getKey());
    108        }
    109        return labels;
    110    }
    111
    112    /**
    113     * {@inheritDoc}
    114     */
    115    @Override
    116    public List<Pair<String, Object>> getContextEntries() {
    117        return contextValues;
    118    }
    119
    120    /**
    121     * Builds the message containing the contextual information.
    122     *
    123     * @param baseMessage  the base exception message <b>without</b> context information appended
    124     * @return the exception message <b>with</b> context information appended, never null
    125     */
    126    @Override
    127    public String getFormattedExceptionMessage(final String baseMessage){
    128        final StringBuilder buffer = new StringBuilder(256);
    129        if (baseMessage != null) {
    130            buffer.append(baseMessage);
    131        }
    132
    133        if (!contextValues.isEmpty()) {
    134            if (buffer.length() > 0) {
    135                buffer.append('\n');
    136            }
    137            buffer.append("Exception Context:\n");
    138
    139            int i = 0;
    140            for (final Pair<String, Object> pair : contextValues) {
    141                buffer.append("\t[");
    142                buffer.append(++i);
    143                buffer.append(':');
    144                buffer.append(pair.getKey());
    145                buffer.append("=");
    146                final Object value = pair.getValue();
    147                if (value == null) {
    148                    buffer.append("null");
    149                } else {
    150                    String valueStr;
    151                    try {
    152                        valueStr = value.toString();
    153                    } catch (final Exception e) {
    154                        valueStr = "Exception thrown on toString(): " + ExceptionUtils.getStackTrace(e);
    155                    }
    156                    buffer.append(valueStr);
    157                }
    158                buffer.append("]\n");
    159            }
    160            buffer.append("---------------------------------");
    161        }
    162        return buffer.toString();
    163    }
    164
    165}