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