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package org.apache.juneau.rest.converters;

import org.apache.juneau.rest.*;
import org.apache.juneau.utils.*;

/**
 * Converter for enabling of {@link PojoQuery} support on response objects returned by a <c>@RestMethod</c> method.
 *
 * <p>
 * When enabled, objects in a POJO tree can be filtered using the functionality described in the {@link PojoQuery}
 * class.
 *
 * <p>
 * The following HTTP request parameters are available for tabular data (e.g. {@code Collections} of {@code Maps},
 * arrays of beans, etc...):
 * <ul class='spaced-list'>
 *    <li>
 *       <c>&amp;s=</c> Search arguments.
 *       <br>Comma-delimited list of key/value pairs representing column names and search tokens.
 *       <br>Example:
 *       <p class='bcode w800'>
 *    &amp;s=name=Bill*,birthDate&gt;2000
 *       </p>
 *    <li>
 *       <c>&amp;v=</c> Visible columns.
 *       <br>Comma-delimited list of column names to display.
 *       <br>Example:
 *       <p class='bcode w800'>
 *    &amp;v=name,birthDate
 *       </p>
 *    <li>
 *       <c>&amp;o=</c> Sort commands.
 *       <br>Comma-delimited list of columns to sort by.
 *       <br>Column names can be suffixed with <js>'+'</js> or <js>'-'</js> to indicate ascending or descending order.
 *       <br>The default is ascending order.
 *       <br>Example:
 *       <p class='bcode w800'>
 *    &amp;o=name,birthDate-
 *       </p>
 *    <li>
 *       <c>&amp;i=</c> Case-insensitive parameter.
 *       <br>Boolean flag for case-insensitive matching on the search parameters.
 *    <li>
 *       <c>&amp;p=</c> - Position parameter.
 *       <br>Only return rows starting at the specified index position (zero-indexed).
 *       <br>Default is {@code 0}.
 *    <li>
 *       <c>&amp;l=</c> Limit parameter.
 *       <br>Only return the specified number of rows.
 *       <br>Default is {@code 0} (meaning return all rows).
 * </ul>
 *
 * <ul class='seealso'>
 *    <li class='jc'>{@link PojoQuery} - Additional information on filtering POJO models.
 *    <li class='jf'>{@link RestContext#REST_converters} - Registering converters with REST resources.
 *    <li class='link'>{@doc juneau-rest-server.Converters}
 * </ul>
 */
public final class Queryable implements RestConverter {

   /**
    * Swagger parameters for this converter.
    */
   public static final String SWAGGER_PARAMS=""
      + "{"
         + "in:'query',"
         + "name:'s',"
         + "description:'"
            + "Search.\n"
            + "Key/value pairs representing column names and search tokens.\n"
            + "\\'*\\' and \\'?\\' can be used as meta-characters in string fields.\n"
            + "\\'>\\', \\'>=\\', \\'<\\', and \\'<=\\' can be used as limits on numeric and date fields.\n"
            + "Date fields can be matched with partial dates (e.g. \\'2018\\' to match any date in the year 2018)."
         + "',"
         + "type:'array',"
         + "collectionFormat:'csv',"
         + "x-examples:{example:'?s=Bill*,birthDate>2000'}"
      + "},"
      + "{"
         + "in:'query',"
         + "name:'v',"
         + "description:'"
            + "View.\n"
            + "Column names to display."
         + "',"
         + "type:'array',"
         + "collectionFormat:'csv',"
         + "x-examples:{example:'?v=name,birthDate'}"
      + "},"
      + "{"
         + "in:'query',"
         + "name:'o',"
         + "description:'"
            + "Order by.\n"
            + "Columns to sort by.\n"
            + "Column names can be suffixed with \\'+\\' or \\'-\\' to indicate ascending or descending order.\n"
            + "The default is ascending order."
         + "',"
         + "type:'array',"
         + "collectionFormat:'csv',"
         + "x-examples:{example:'?o=name,birthDate-'}"
      + "},"
      + "{"
         + "in:'query',"
         + "name:'i',"
         + "description:'"
            + "Case-insensitive.\n"
            + "Flag for case-insensitive matching on the search parameters."
         + "',"
         + "type:'boolean',"
         + "x-examples:{example:'?i=true'}"
      + "},"
      + "{"
         + "in:'query',"
         + "name:'p',"
         + "description:'"
            + "Position.\n"
            + "Only return rows starting at the specified index position (zero-indexed).\n"
            + "Default is 0"
         + "',"
         + "type:'integer',"
         + "x-examples:{example:'?p=100'}"
      + "},"
      + "{"
         + "in:'query',"
         + "name:'l',"
         + "description:'"
            + "Limit.\n"
            + "Only return the specified number of rows.\n"
            + "Default is 0 (meaning return all rows)."
         + "',"
         + "type:'integer',"
         + "x-examples:{example:'?l=100'}"
      + "}"
   ;

   @Override /* RestConverter */
   public Object convert(RestRequest req, Object o) {
      if (o == null)
         return null;
      SearchArgs searchArgs = req.getQuery().getSearchArgs();
      if (searchArgs == null)
         return o;
      return new PojoQuery(o, req.getBeanSession()).filter(searchArgs);
   }
}