/*
    * 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.logging.log4j.core.pattern;
  
  import java.util.List;
  
  import org.apache.logging.log4j.core.LogEvent;
  import org.apache.logging.log4j.core.config.Configuration;
  import org.apache.logging.log4j.core.config.plugins.Plugin;
  import org.apache.logging.log4j.core.layout.PatternLayout;
  import org.apache.logging.log4j.util.PerformanceSensitive;
  
  /**
   * VariablesNotEmpty pattern converter.
   */
  @Plugin(name = "notEmpty", category = PatternConverter.CATEGORY)
  @ConverterKeys({ "notEmpty", "varsNotEmpty", "variablesNotEmpty", })
  @PerformanceSensitive("allocation")
  public final class VariablesNotEmptyReplacementConverter extends LogEventPatternConverter {
  
      private final List<PatternFormatter> formatters;
  
      /**
       * Constructs the converter.
       *
       * @param formatters
       *            The PatternFormatters to generate the text to manipulate.
       */
      private VariablesNotEmptyReplacementConverter(final List<PatternFormatter> formatters) {
          super("notEmpty", "notEmpty");
          this.formatters = formatters;
      }
  
      /**
       * Gets an instance of the class.
       *
       * @param config
       *            The current Configuration.
       * @param options
       *            pattern options, may be null.
       * @return instance of class.
       */
      public static VariablesNotEmptyReplacementConverter newInstance(final Configuration config,
              final String[] options) {
          if (options.length != 1) {
              LOGGER.error("Incorrect number of options on varsNotEmpty. Expected 1 received " + options.length);
              return null;
          }
          if (options[0] == null) {
              LOGGER.error("No pattern supplied on varsNotEmpty");
              return null;
          }
          final PatternParser parser = PatternLayout.createPatternParser(config);
          final List<PatternFormatter> formatters = parser.parse(options[0]);
          return new VariablesNotEmptyReplacementConverter(formatters);
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public void format(final LogEvent event, final StringBuilder toAppendTo) {
          final int start = toAppendTo.length();
          boolean allVarsEmpty = true;
          boolean hasVars = false;
          for (int i = 0; i < formatters.size(); i++) {
              final PatternFormatter formatter = formatters.get(i);
              final int formatterStart = toAppendTo.length();
              formatter.format(event, toAppendTo);
              if (formatter.getConverter().isVariable()) {
                  hasVars = true;
                  allVarsEmpty = allVarsEmpty && (toAppendTo.length() == formatterStart);
              }
          }
          if (!hasVars || allVarsEmpty) {
              toAppendTo.setLength(start); // remove formatter results
          }
      }
  }