juneau-rest/juneau-rest-server/src/main/java/org/apache/juneau/rest/converters/Queryable.java

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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);
	}
}