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// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
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// ***************************************************************************************************************************
package org.apache.juneau.rest;

import static org.apache.juneau.internal.ArrayUtils.*;
import static org.apache.juneau.internal.StringUtils.*;

import java.lang.reflect.*;
import java.util.*;

import javax.servlet.http.*;

import org.apache.juneau.*;
import org.apache.juneau.httppart.*;
import org.apache.juneau.internal.*;
import org.apache.juneau.json.*;
import org.apache.juneau.oapi.*;
import org.apache.juneau.parser.*;
import org.apache.juneau.rest.exception.*;
import org.apache.juneau.utils.*;

/**
 * Represents the query parameters in an HTTP request.
 *
 * <p>
 * Similar in functionality to the {@link HttpServletRequest#getParameter(String)} except only looks in the URL string, not parameters from
 * URL-Encoded FORM posts.
 * <br>This can be useful in cases where you're using GET parameters on FORM POSTs, and you don't want the body of the request to be read.
 *
 * <h5 class='section'>See Also:</h5>
 * <ul>
 *    <li class='link'>{@doc juneau-rest-server.RestMethod.RequestQuery}
 * </ul>
 */
@SuppressWarnings("unchecked")
public final class RequestQuery extends LinkedHashMap<String,String[]> {
   private static final long serialVersionUID = 1L;

   private final RestRequest req;
   private HttpPartParser parser;

   RequestQuery(RestRequest req) {
      this.req = req;
   }

   RequestQuery parser(HttpPartParser parser) {
      this.parser = parser;
      return this;
   }

   /*
    * Create a copy of the request query parameters.
    */
   RequestQuery copy() {
      RequestQuery rq = new RequestQuery(req);
      rq.putAll(this);
      return rq;
   }

   /**
    * Adds default entries to these query parameters.
    *
    * <p>
    * This includes the default queries defined at the resource and method levels.
    *
    * @param defaultEntries
    *    The default entries.
    *    <br>Can be <jk>null</jk>.
    * @return This object (for method chaining).
    */
   public RequestQuery addDefault(Map<String,Object> defaultEntries) {
      if (defaultEntries != null) {
         for (Map.Entry<String,Object> e : defaultEntries.entrySet()) {
            String key = e.getKey();
            Object value = e.getValue();
            String[] v = get(key);
            if (v == null || v.length == 0 || StringUtils.isEmpty(v[0]))
               put(key, asStrings(value));
         }
      }
      return this;
   }

   /**
    * Adds a default entries to these query parameters.
    *
    * <p>
    * Similar to {@link #put(String, Object)} but doesn't override existing values.
    *
    * @param name
    *    The query parameter name.
    * @param value
    *    The query parameter value.
    *    <br>Converted to a String using <code>toString()</code>.
    *    <br>Ignored if value is <jk>null</jk> or blank.
    * @return This object (for method chaining).
    */
   public RequestQuery addDefault(String name, Object value) {
      return addDefault(Collections.singletonMap(name, value));
   }

   /**
    * Sets a request query parameter value.
    *
    * <p>
    * This overwrites any existing value.
    *
    * @param name The parameter name.
    * @param value
    *    The parameter value.
    *    <br>Can be <jk>null</jk>.
    */
   public void put(String name, Object value) {
      if (value == null)
         put(name, null);
      else
         put(name, asStrings(value));
   }

   /**
    * Returns a query parameter value as a string.
    *
    * <p>
    * If multiple query parameters have the same name, this returns only the first instance.
    *
    * @param name The URL parameter name.
    * @return
    *    The parameter value, or <jk>null</jk> if parameter not specified or has no value (e.g. <js>"&amp;foo"</js>).
    */
   public String getString(String name) {
      String[] v = get(name);
      if (v == null || v.length == 0)
         return null;

      // Fix for behavior difference between Tomcat and WAS.
      // getParameter("foo") on "&foo" in Tomcat returns "".
      // getParameter("foo") on "&foo" in WAS returns null.
      if (v.length == 1 && v[0] == null)
         return "";

      return v[0];
   }

   /**
    * Same as {@link #getString(String)} but returns the specified default value if the query parameter was not
    * specified.
    *
    * @param name The URL parameter name.
    * @param def The default value.
    * @return
    *    The parameter value, or the default value if parameter not specified or has no value (e.g. <js>"&amp;foo"</js>).
    */
   public String getString(String name, String def) {
      String s = getString(name);
      return StringUtils.isEmpty(s) ? def : s;
   }

   /**
    * Same as {@link #getString(String)} but converts the value to an integer.
    *
    * @param name The URL parameter name.
    * @return
    *    The parameter value, or <code>0</code> if parameter not specified or has no value (e.g. <js>"&amp;foo"</js>).
    */
   public int getInt(String name) {
      return getInt(name, 0);
   }

   /**
    * Same as {@link #getString(String,String)} but converts the value to an integer.
    *
    * @param name The URL parameter name.
    * @param def The default value.
    * @return
    *    The parameter value, or the default value if parameter not specified or has no value (e.g. <js>"&amp;foo"</js>).
    */
   public int getInt(String name, int def) {
      String s = getString(name);
      return StringUtils.isEmpty(s) ? def : Integer.parseInt(s);
   }

   /**
    * Same as {@link #getString(String)} but converts the value to a boolean.
    *
    * @param name The URL parameter name.
    * @return
    *    The parameter value, or <jk>false</jk> if parameter not specified or has no value (e.g. <js>"&amp;foo"</js>).
    */
   public boolean getBoolean(String name) {
      return getBoolean(name, false);
   }

   /**
    * Same as {@link #getString(String,String)} but converts the value to a boolean.
    *
    * @param name The URL parameter name.
    * @param def The default value.
    * @return
    *    The parameter value, or the default value if parameter not specified or has no value (e.g. <js>"&amp;foo"</js>).
    */
   public boolean getBoolean(String name, boolean def) {
      String s = getString(name);
      return StringUtils.isEmpty(s) ? def : Boolean.parseBoolean(s);
   }

   /**
    * Returns the specified query parameter value converted to a POJO using the {@link HttpPartParser} registered with the resource.
    *
    * <h5 class='section'>Examples:</h5>
    * <p class='bcode w800'>
    *    <jc>// Parse into an integer.</jc>
    *    <jk>int</jk> myparam = query.get(<js>"myparam"</js>, <jk>int</jk>.<jk>class</jk>);
    *
    *    <jc>// Parse into an int array.</jc>
    *    <jk>int</jk>[] myparam = query.get(<js>"myparam"</js>, <jk>int</jk>[].<jk>class</jk>);

    *    <jc>// Parse into a bean.</jc>
    *    MyBean myparam = query.get(<js>"myparam"</js>, MyBean.<jk>class</jk>);
    *
    *    <jc>// Parse into a linked-list of objects.</jc>
    *    List myparam = query.get(<js>"myparam"</js>, LinkedList.<jk>class</jk>);
    *
    *    <jc>// Parse into a map of object keys/values.</jc>
    *    Map myparam = query.get(<js>"myparam"</js>, TreeMap.<jk>class</jk>);
    * </p>
    *
    * <h5 class='section'>See Also:</h5>
    * <ul>
    *    <li class='jf'>{@link RestContext#REST_partParser}
    * </ul>
    *
    * @param name The parameter name.
    * @param type The class type to convert the parameter value to.
    * @param <T> The class type to convert the parameter value to.
    * @return The parameter value converted to the specified class type.
    * @throws BadRequest Thrown if input could not be parsed.
    * @throws InternalServerError Thrown if any other exception occurs.
    */
   public <T> T get(String name, Class<T> type) throws BadRequest, InternalServerError {
      return getInner(null, null, name, null, getClassMeta(type));
   }

   /**
    * Same as {@link #get(String, Class)} but allows you to override the part parser.
    *
    * @param parser
    *    The parser to use for parsing the string value.
    *    <br>If <jk>null</jk>, uses the part parser defined on the resource/method.
    * @param schema
    *    The schema object that defines the format of the input.
    *    <br>If <jk>null</jk>, defaults to the schema defined on the parser.
    *    <br>If that's also <jk>null</jk>, defaults to {@link HttpPartSchema#DEFAULT}.
    *    <br>Only used if parser is schema-aware (e.g. {@link OpenApiParser}).
    * @param name The parameter name.
    * @param type The class type to convert the parameter value to.
    * @param <T> The class type to convert the parameter value to.
    * @return The parameter value converted to the specified class type.
    * @throws BadRequest Thrown if input could not be parsed or fails schema validation.
    * @throws InternalServerError Thrown if any other exception occurs.
    */
   public <T> T get(HttpPartParser parser, HttpPartSchema schema, String name, Class<T> type) throws BadRequest, InternalServerError {
      return getInner(parser, schema, name, null, getClassMeta(type));
   }

   /**
    * Same as {@link #get(String, Class)} except returns a default value if not found.
    *
    * @param name The parameter name.
    * @param def The default value if the parameter was not specified or is <jk>null</jk>.
    * @param type The class type to convert the parameter value to.
    * @param <T> The class type to convert the parameter value to.
    * @return The parameter value converted to the specified class type.
    * @throws BadRequest Thrown if input could not be parsed.
    * @throws InternalServerError Thrown if any other exception occurs.
    */
   public <T> T get(String name, T def, Class<T> type) throws BadRequest, InternalServerError {
      return getInner(null, null, name, def, getClassMeta(type));
   }

   /**
    * Same as {@link #get(String, Object, Class)} but allows you to override the part parser.
    *
    * @param parser
    *    The parser to use for parsing the string value.
    *    <br>If <jk>null</jk>, uses the part parser defined on the resource/method.
    * @param schema
    *    The schema object that defines the format of the input.
    *    <br>If <jk>null</jk>, defaults to the schema defined on the parser.
    *    <br>If that's also <jk>null</jk>, defaults to {@link HttpPartSchema#DEFAULT}.
    *    <br>Only used if parser is schema-aware (e.g. {@link OpenApiParser}).
    * @param name The parameter name.
    * @param def The default value if the parameter was not specified or is <jk>null</jk>.
    * @param type The class type to convert the parameter value to.
    * @param <T> The class type to convert the parameter value to.
    * @return The parameter value converted to the specified class type.
    * @throws BadRequest Thrown if input could not be parsed or fails schema validation.
    * @throws InternalServerError Thrown if any other exception occurs.
    */
   public <T> T get(HttpPartParser parser, HttpPartSchema schema, String name, T def, Class<T> type) throws BadRequest, InternalServerError {
      return getInner(parser, schema, name, def, getClassMeta(type));
   }

   /**
    * Returns the specified query parameter value converted to a POJO using the {@link HttpPartParser} registered with the resource.
    *
    * <p>
    * Similar to {@link #get(String,Class)} but allows for complex collections of POJOs to be created.
    *
    * <h5 class='section'>Examples:</h5>
    * <p class='bcode w800'>
    *    <jc>// Parse into a linked-list of strings.</jc>
    *    List&lt;String&gt; myparam = query.get(<js>"myparam"</js>, LinkedList.<jk>class</jk>, String.<jk>class</jk>);
    *
    *    <jc>// Parse into a linked-list of linked-lists of strings.</jc>
    *    List&lt;List&lt;String&gt;&gt; myparam = query.get(<js>"myparam"</js>, LinkedList.<jk>class</jk>, LinkedList.<jk>class</jk>, String.<jk>class</jk>);
    *
    *    <jc>// Parse into a map of string keys/values.</jc>
    *    Map&lt;String,String&gt; myparam = query.get(<js>"myparam"</js>, TreeMap.<jk>class</jk>, String.<jk>class</jk>, String.<jk>class</jk>);
    *
    *    <jc>// Parse into a map containing string keys and values of lists containing beans.</jc>
    *    Map&lt;String,List&lt;MyBean&gt;&gt; myparam = query.get(<js>"myparam"</js>, TreeMap.<jk>class</jk>, String.<jk>class</jk>, List.<jk>class</jk>, MyBean.<jk>class</jk>);
    * </p>
    *
    * <h5 class='section'>Notes:</h5>
    * <ul class='spaced-list'>
    *    <li>
    *       <code>Collections</code> must be followed by zero or one parameter representing the value type.
    *    <li>
    *       <code>Maps</code> must be followed by zero or two parameters representing the key and value types.
    * </ul>
    *
    * <h5 class='section'>See Also:</h5>
    * <ul>
    *    <li class='jf'>{@link RestContext#REST_partParser}
    * </ul>
    *
    * @param name The parameter name.
    * @param type
    *    The type of object to create.
    *    <br>Can be any of the following: {@link ClassMeta}, {@link Class}, {@link ParameterizedType}, {@link GenericArrayType}
    * @param args
    *    The type arguments of the class if it's a collection or map.
    *    <br>Can be any of the following: {@link ClassMeta}, {@link Class}, {@link ParameterizedType}, {@link GenericArrayType}
    *    <br>Ignored if the main type is not a map or collection.
    * @param <T> The class type to convert the parameter value to.
    * @return The parameter value converted to the specified class type.
    * @throws BadRequest Thrown if input could not be parsed.
    * @throws InternalServerError Thrown if any other exception occurs.
    */
   public <T> T get(String name, Type type, Type...args) throws BadRequest, InternalServerError {
      return getInner(null, null, name, null, (ClassMeta<T>)getClassMeta(type, args));
   }

   /**
    * Same as {@link #get(String, Type, Type...)} but allows you to override the part parser.
    *
    * @param parser
    *    The parser to use for parsing the string value.
    *    <br>If <jk>null</jk>, uses the part parser defined on the resource/method.
    * @param schema
    *    The schema object that defines the format of the input.
    *    <br>If <jk>null</jk>, defaults to the schema defined on the parser.
    *    <br>If that's also <jk>null</jk>, defaults to {@link HttpPartSchema#DEFAULT}.
    *    <br>Only used if parser is schema-aware (e.g. {@link OpenApiParser}).
    * @param name The parameter name.
    * @param type
    *    The type of object to create.
    *    <br>Can be any of the following: {@link ClassMeta}, {@link Class}, {@link ParameterizedType}, {@link GenericArrayType}
    * @param args
    *    The type arguments of the class if it's a collection or map.
    *    <br>Can be any of the following: {@link ClassMeta}, {@link Class}, {@link ParameterizedType}, {@link GenericArrayType}
    *    <br>Ignored if the main type is not a map or collection.
    * @param <T> The class type to convert the parameter value to.
    * @return The parameter value converted to the specified class type.
    * @throws BadRequest Thrown if input could not be parsed or fails schema validation.
    * @throws InternalServerError Thrown if any other exception occurs.
    */
   public <T> T get(HttpPartParser parser, HttpPartSchema schema, String name, Type type, Type...args) throws BadRequest, InternalServerError {
      return getInner(parser, schema, name, null, (ClassMeta<T>)getClassMeta(type, args));
   }

   /**
    * Same as {@link #get(String, Class)} except returns a default value if not found.
    *
    * @param name The parameter name.
    * @param type
    *    The type of object to create.
    *    <br>Can be any of the following: {@link ClassMeta}, {@link Class}, {@link ParameterizedType}, {@link GenericArrayType}
    * @param args
    *    The type arguments of the class if it's a collection or map.
    *    <br>Can be any of the following: {@link ClassMeta}, {@link Class}, {@link ParameterizedType}, {@link GenericArrayType}
    *    <br>Ignored if the main type is not a map or collection.
    * @param def The default value if the parameter was not specified or is <jk>null</jk>.
    * @param <T> The class type to convert the parameter value to.
    * @return The parameter value converted to the specified class type.
    * @throws BadRequest Thrown if input could not be parsed.
    * @throws InternalServerError Thrown if any other exception occurs.
    */
   public <T> T get(String name, T def, Type type, Type...args) throws BadRequest, InternalServerError {
      return getInner(null, null, name, def, (ClassMeta<T>)getClassMeta(type, args));
   }

   /**
    * Same as {@link #get(String, Object, Type, Type...)} but allows you to override the part parser.
    *
    * @param parser
    *    The parser to use for parsing the string value.
    *    <br>If <jk>null</jk>, uses the part parser defined on the resource/method.
    * @param schema
    *    The schema object that defines the format of the input.
    *    <br>If <jk>null</jk>, defaults to the schema defined on the parser.
    *    <br>If that's also <jk>null</jk>, defaults to {@link HttpPartSchema#DEFAULT}.
    *    <br>Only used if parser is schema-aware (e.g. {@link OpenApiParser}).
    * @param name The parameter name.
    * @param type
    *    The type of object to create.
    *    <br>Can be any of the following: {@link ClassMeta}, {@link Class}, {@link ParameterizedType}, {@link GenericArrayType}
    * @param args
    *    The type arguments of the class if it's a collection or map.
    *    <br>Can be any of the following: {@link ClassMeta}, {@link Class}, {@link ParameterizedType}, {@link GenericArrayType}
    *    <br>Ignored if the main type is not a map or collection.
    * @param def The default value if the parameter was not specified or is <jk>null</jk>.
    * @param <T> The class type to convert the parameter value to.
    * @return The parameter value converted to the specified class type.
    * @throws BadRequest Thrown if input could not be parsed or fails schema validation.
    * @throws InternalServerError Thrown if any other exception occurs.
    */
   public <T> T get(HttpPartParser parser, HttpPartSchema schema, String name, T def, Type type, Type...args) throws BadRequest, InternalServerError {
      return getInner(parser, schema, name, def, (ClassMeta<T>)getClassMeta(type, args));
   }

   /**
    * Same as {@link #get(String, Class)} except for use on multi-part parameters
    * (e.g. <js>"&amp;key=1&amp;key=2&amp;key=3"</js> instead of <js>"&amp;key=@(1,2,3)"</js>).
    *
    * <p>
    * This method must only be called when parsing into classes of type Collection or array.
    *
    * @param name The query parameter name.
    * @param c The class type to convert the parameter value to.
    * @param <T> The class type to convert the parameter value to.
    * @return The query parameter value converted to the specified class type.
    * @throws BadRequest Thrown if input could not be parsed.
    * @throws InternalServerError Thrown if any other exception occurs.
    */
   public <T> T getAll(String name, Class<T> c) throws BadRequest, InternalServerError {
      return getAllInner(null, null, name, null, getClassMeta(c));
   }

   /**
    * Same as {@link #get(String, Type, Type...)} except for use on multi-part parameters
    * (e.g. <js>"&amp;key=1&amp;key=2&amp;key=3"</js> instead of <js>"&amp;key=@(1,2,3)"</js>).
    *
    * <p>
    * This method must only be called when parsing into classes of type Collection or array.
    *
    * @param name The query parameter name.
    * @param type
    *    The type of object to create.
    *    <br>Can be any of the following: {@link ClassMeta}, {@link Class}, {@link ParameterizedType}, {@link GenericArrayType}
    * @param args
    *    The type arguments of the class if it's a collection or map.
    *    <br>Can be any of the following: {@link ClassMeta}, {@link Class}, {@link ParameterizedType}, {@link GenericArrayType}
    *    <br>Ignored if the main type is not a map or collection.
    * @param <T> The class type to convert the parameter value to.
    * @return The query parameter value converted to the specified class type.
    * @throws BadRequest Thrown if input could not be parsed.
    * @throws InternalServerError Thrown if any other exception occurs.
    */
   public <T> T getAll(String name, Type type, Type...args) throws BadRequest, InternalServerError {
      return getAllInner(null, null, name, null, (ClassMeta<T>)getClassMeta(type, args));
   }

   /**
    * Same as {@link #getAll(String, Type, Type...)} but allows you to override the part parser.
    *
    * @param parser
    *    The parser to use for parsing the string value.
    *    <br>If <jk>null</jk>, uses the part parser defined on the resource/method.
    * @param schema
    *    The schema object that defines the format of the input.
    *    <br>If <jk>null</jk>, defaults to the schema defined on the parser.
    *    <br>If that's also <jk>null</jk>, defaults to {@link HttpPartSchema#DEFAULT}.
    *    <br>Only used if parser is schema-aware (e.g. {@link OpenApiParser}).
    * @param name The query parameter name.
    * @param type
    *    The type of object to create.
    *    <br>Can be any of the following: {@link ClassMeta}, {@link Class}, {@link ParameterizedType}, {@link GenericArrayType}
    * @param args
    *    The type arguments of the class if it's a collection or map.
    *    <br>Can be any of the following: {@link ClassMeta}, {@link Class}, {@link ParameterizedType}, {@link GenericArrayType}
    *    <br>Ignored if the main type is not a map or collection.
    * @param <T> The class type to convert the parameter value to.
    * @return The query parameter value converted to the specified class type.
    * @throws BadRequest Thrown if input could not be parsed or fails schema validation.
    * @throws InternalServerError Thrown if any other exception occurs.
    */
   public <T> T getAll(HttpPartParser parser, HttpPartSchema schema, String name, Type type, Type...args) throws BadRequest, InternalServerError {
      return getAllInner(parser, schema, name, null, (ClassMeta<T>)getClassMeta(type, args));
   }

   /**
    * Returns <jk>true</jk> if the request contains any of the specified query parameters.
    *
    * @param params The list of parameters to check for.
    * @return <jk>true</jk> if the request contains any of the specified query parameters.
    */
   public boolean containsAnyKeys(String...params) {
      for (String p : params)
         if (containsKey(p))
            return true;
      return false;
   }

   /**
    * Locates the special search query arguments in the query and returns them as a {@link SearchArgs} object.
    *
    * <p>
    * The query arguments are as follows:
    * <ul class='spaced-list'>
    *    <li>
    *       <js>"&amp;s="</js> - A comma-delimited list of column-name/search-token pairs.
    *       <br>Example: <js>"&amp;s=column1=foo*,column2=*bar"</js>
    *    <li>
    *       <js>"&amp;v="</js> - A comma-delimited list column names to view.
    *       <br>Example: <js>"&amp;v=column1,column2"</js>
    *    <li>
    *       <js>"&amp;o="</js> - A comma-delimited list column names to sort by.
    *       <br>Column names can be suffixed with <js>'-'</js> to indicate descending order.
    *       <br>Example: <js>"&amp;o=column1,column2-"</js>
    *    <li>
    *       <js>"&amp;p="</js> - The zero-index row number of the first row to display.
    *       <br>Example: <js>"&amp;p=100"</js>
    *    <li>
    *       <js>"&amp;l="</js> - The number of rows to return.
    *       <br><code>0</code> implies return all rows.
    *       <br>Example: <js>"&amp;l=100"</js>
    *    <li>
    *       <js>"&amp;i="</js> - The case-insensitive search flag.
    *       <br>Example: <js>"&amp;i=true"</js>
    * </ul>
    *
    * <h5 class='section'>Notes:</h5>
    * <ul class='spaced-list'>
    *    <li>
    *       Whitespace is trimmed in the parameters.
    * </ul>
    *
    * @return
    *    A new {@link SearchArgs} object initialized with the special search query arguments.
    *    <br>Returns <jk>null</jk> if no search arguments were found.
    */
   public SearchArgs getSearchArgs() {
      if (hasAny("s","v","o","p","l","i")) {
         return new SearchArgs.Builder()
            .search(getString("s"))
            .view(getString("v"))
            .sort(getString("o"))
            .position(getInt("p"))
            .limit(getInt("l"))
            .ignoreCase(getBoolean("i"))
            .build();
      }
      return null;
   }

   /**
    * Returns <jk>true</jk> if the query parameters contains any of the specified names.
    *
    * @param paramNames The parameter names to check for.
    * @return <jk>true</jk> if the query parameters contains any of the specified names.
    */
   public boolean hasAny(String...paramNames) {
      for (String p : paramNames)
         if (containsKey(p))
            return true;
      return false;
   }

   /* Workhorse method */
   private <T> T getInner(HttpPartParser parser, HttpPartSchema schema, String name, T def, ClassMeta<T> cm) throws BadRequest, InternalServerError {
      try {
         if (cm.isMapOrBean() && isOneOf(name, "*", "")) {
            ObjectMap m = new ObjectMap();
            for (Map.Entry<String,String[]> e : this.entrySet()) {
               String k = e.getKey();
               HttpPartSchema pschema = schema == null ? null : schema.getProperty(k);
               ClassMeta<?> cm2 = cm.getValueType();
               if (cm.getValueType().isCollectionOrArray())
                  m.put(k, getAllInner(parser, pschema, k, null, cm2));
               else
                  m.put(k, getInner(parser, pschema, k, null, cm2));
            }
            return req.getBeanSession().convertToType(m, cm);
         }
         T t = parse(parser, schema, getString(name), cm);
         return (t == null ? def : t);
      } catch (SchemaValidationException e) {
         throw new BadRequest(e, "Validation failed on query parameter ''{0}''. ", name);
      } catch (ParseException e) {
         throw new BadRequest(e, "Could not parse query parameter ''{0}''.", name) ;
      } catch (Exception e) {
         throw new InternalServerError(e, "Could not parse query parameter ''{0}''.", name) ;
      }
   }

   /* Workhorse method */
   @SuppressWarnings("rawtypes")
   private <T> T getAllInner(HttpPartParser parser, HttpPartSchema schema, String name, T def, ClassMeta<T> cm) throws BadRequest, InternalServerError {
      String[] p = get(name);
      if (p == null)
         return def;
      if (schema == null)
         schema = HttpPartSchema.DEFAULT;
      try {
         if (cm.isArray()) {
            List c = new ArrayList();
            for (int i = 0; i < p.length; i++)
               c.add(parse(parser, schema.getItems(), p[i], cm.getElementType()));
            return (T)toArray(c, cm.getElementType().getInnerClass());
         } else if (cm.isCollection()) {
            Collection c = (Collection)(cm.canCreateNewInstance() ? cm.newInstance() : new ObjectList());
            for (int i = 0; i < p.length; i++)
               c.add(parse(parser, schema.getItems(), p[i], cm.getElementType()));
            return (T)c;
         }
      } catch (SchemaValidationException e) {
         throw new BadRequest(e, "Validation failed on query parameter ''{0}''. ", name);
      } catch (ParseException e) {
         throw new BadRequest(e, "Could not parse query parameter ''{0}''.", name) ;
      } catch (Exception e) {
         throw new InternalServerError(e, "Could not parse query parameter ''{0}''.", name) ;
      }
      throw new InternalServerError("Invalid call to getParameters(String, ClassMeta).  Class type must be a Collection or array.");
   }

   private <T> T parse(HttpPartParser parser, HttpPartSchema schema, String val, ClassMeta<T> c) throws SchemaValidationException, ParseException {
      if (parser == null)
         parser = this.parser;
      return parser.createPartSession(req.getParserSessionArgs()).parse(HttpPartType.QUERY, schema, val, c);
   }

   /**
    * Converts the query parameters to a readable string.
    *
    * @param sorted Sort the query parameters by name.
    * @return A JSON string containing the contents of the query parameters.
    */
   public String toString(boolean sorted) {
      Map<String,Object> m = (sorted ? new TreeMap<String,Object>() : new LinkedHashMap<String,Object>());
      for (Map.Entry<String,String[]> e : this.entrySet()) {
         String[] v = e.getValue();
         m.put(e.getKey(), v.length == 1 ? v[0] : v);
      }
      return SimpleJsonSerializer.DEFAULT.toString(m);
   }

   /**
    * Converts this object to a query string.
    *
    * <p>
    * Returned query string does not start with <js>'?'</js>.
    *
    * @return A new query string, or an empty string if this object is empty.
    */
   public String toQueryString() {
      StringBuilder sb = new StringBuilder();
      for (Map.Entry<String,String[]> e : this.entrySet()) {
         for (int i = 0; i < e.getValue().length; i++) {
            if (sb.length() > 0)
               sb.append("&");
            sb.append(urlEncode(e.getKey())).append('=').append(urlEncode(e.getValue()[i]));
         }
      }
      return sb.toString();
   }

   @Override /* Object */
   public String toString() {
      return toString(false);
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Helper methods
   //-----------------------------------------------------------------------------------------------------------------

   private <T> ClassMeta<T> getClassMeta(Type type, Type...args) {
      return req.getBeanSession().getClassMeta(type, args);
   }

   private <T> ClassMeta<T> getClassMeta(Class<T> type) {
      return req.getBeanSession().getClassMeta(type);
   }
}