/*

  * Licensed to the Apache Software Foundation (ASF) under one or more

  * contributor license agreements.  See the NOTICE file distributed with

  * this work for additional information regarding copyright ownership.

  * The ASF licenses this file to You under the Apache License, Version 2.0

  * (the "License"); you may not use this file except in compliance with

  * the License.  You may obtain a copy of the License at

  * 

  *      http://www.apache.org/licenses/LICENSE-2.0

  * 

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.apache.commons.lang3.exception;

 import java.io.Serializable;

 import java.util.ArrayList;

 import java.util.HashSet;

 import java.util.Iterator;

 import java.util.List;

 import java.util.Set;

 import org.apache.commons.lang3.StringUtils;

 import org.apache.commons.lang3.tuple.ImmutablePair;

 import org.apache.commons.lang3.tuple.Pair;

 /**

  * Default implementation of the context storing the label-value pairs for contexted exceptions.

  * <p>

  * This implementation is serializable, however this is dependent on the values that

  * are added also being serializable.

  * </p>

  * 

  * @see ContextedException

  * @see ContextedRuntimeException

  * @since 3.0

  */

 public class DefaultExceptionContext implements ExceptionContext, Serializable {

     /** The serialization version. */

     private static final long serialVersionUID = 20110706L;

     /** The list storing the label-data pairs. */

     private final List<Pair<String, Object>> contextValues = new ArrayList<Pair<String,Object>>();

     /**

      * {@inheritDoc}

      */

     @Override

     public DefaultExceptionContext addContextValue(final String label, final Object value) {

         contextValues.add(new ImmutablePair<String, Object>(label, value));

         return this;

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public DefaultExceptionContext setContextValue(final String label, final Object value) {

         for (final Iterator<Pair<String, Object>> iter = contextValues.iterator(); iter.hasNext();) {

             final Pair<String, Object> p = iter.next();

             if (StringUtils.equals(label, p.getKey())) {

                 iter.remove();

             }

         }

         addContextValue(label, value);

         return this;

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public List<Object> getContextValues(final String label) {

         final List<Object> values = new ArrayList<Object>();

         for (final Pair<String, Object> pair : contextValues) {

             if (StringUtils.equals(label, pair.getKey())) {

                 values.add(pair.getValue());

             }

         }

         return values;

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public Object getFirstContextValue(final String label) {

         for (final Pair<String, Object> pair : contextValues) {

             if (StringUtils.equals(label, pair.getKey())) {

                 return pair.getValue();

             }

         }

         return null;

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public Set<String> getContextLabels() {

         final Set<String> labels = new HashSet<String>();

         for (final Pair<String, Object> pair : contextValues) {

             labels.add(pair.getKey());

         }

         return labels;

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public List<Pair<String, Object>> getContextEntries() {

         return contextValues;

     }

     /**

      * Builds the message containing the contextual information.

      * 

      * @param baseMessage  the base exception message <b>without</b> context information appended

      * @return the exception message <b>with</b> context information appended, never null

      */

     @Override

     public String getFormattedExceptionMessage(final String baseMessage){

         final StringBuilder buffer = new StringBuilder(256);

         if (baseMessage != null) {

             buffer.append(baseMessage);

         }

         if (contextValues.size() > 0) {

             if (buffer.length() > 0) {

                 buffer.append('\n');

             }

             buffer.append("Exception Context:\n");

             int i = 0;

             for (final Pair<String, Object> pair : contextValues) {

                 buffer.append("\t[");

                 buffer.append(++i);

                 buffer.append(':');

                 buffer.append(pair.getKey());

                 buffer.append("=");

                 final Object value = pair.getValue();

                 if (value == null) {

                     buffer.append("null");

                 } else {

                     String valueStr;

                     try {

                         valueStr = value.toString();

                     } catch (final Exception e) {

                         valueStr = "Exception thrown on toString(): " + ExceptionUtils.getStackTrace(e);

                     }

                     buffer.append(valueStr);

                 }

                 buffer.append("]\n");

             }

             buffer.append("---------------------------------");

         }

         return buffer.toString();

     }

 }