001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019package org.apache.hadoop.lib.wsrs;
020
021import com.google.common.collect.Lists;
022import com.sun.jersey.api.core.HttpContext;
023import com.sun.jersey.core.spi.component.ComponentContext;
024import com.sun.jersey.core.spi.component.ComponentScope;
025import com.sun.jersey.server.impl.inject.AbstractHttpContextInjectable;
026import com.sun.jersey.spi.inject.Injectable;
027import com.sun.jersey.spi.inject.InjectableProvider;
028import org.apache.hadoop.classification.InterfaceAudience;
029
030import javax.ws.rs.core.Context;
031import javax.ws.rs.core.MultivaluedMap;
032import java.lang.reflect.Type;
033import java.text.MessageFormat;
034import java.util.HashMap;
035import java.util.List;
036import java.util.Map;
037
038/**
039 * Jersey provider that parses the request parameters based on the
040 * given parameter definition. 
041 */
042@InterfaceAudience.Private
043public class ParametersProvider
044  extends AbstractHttpContextInjectable<Parameters>
045  implements InjectableProvider<Context, Type> {
046
047  private String driverParam;
048  private Class<? extends Enum> enumClass;
049  private Map<Enum, Class<Param<?>>[]> paramsDef;
050
051  public ParametersProvider(String driverParam, Class<? extends Enum> enumClass,
052                            Map<Enum, Class<Param<?>>[]> paramsDef) {
053    this.driverParam = driverParam;
054    this.enumClass = enumClass;
055    this.paramsDef = paramsDef;
056  }
057
058  @Override
059  @SuppressWarnings("unchecked")
060  public Parameters getValue(HttpContext httpContext) {
061    Map<String, List<Param<?>>> map = new HashMap<String, List<Param<?>>>();
062    Map<String, List<String>> queryString =
063      httpContext.getRequest().getQueryParameters();
064    String str = ((MultivaluedMap<String, String>) queryString).
065        getFirst(driverParam);
066    if (str == null) {
067      throw new IllegalArgumentException(
068        MessageFormat.format("Missing Operation parameter [{0}]",
069                             driverParam));
070    }
071    Enum op;
072    try {
073      op = Enum.valueOf(enumClass, str.toUpperCase());
074    } catch (IllegalArgumentException ex) {
075      throw new IllegalArgumentException(
076        MessageFormat.format("Invalid Operation [{0}]", str));
077    }
078    if (!paramsDef.containsKey(op)) {
079      throw new IllegalArgumentException(
080        MessageFormat.format("Unsupported Operation [{0}]", op));
081    }
082    for (Class<Param<?>> paramClass : paramsDef.get(op)) {
083      Param<?> param = newParam(paramClass);
084      List<Param<?>> paramList = Lists.newArrayList();
085      List<String> ps = queryString.get(param.getName());
086      if (ps != null) {
087        for (String p : ps) {
088          try {
089            param.parseParam(p);
090          }
091          catch (Exception ex) {
092            throw new IllegalArgumentException(ex.toString(), ex);
093          }
094          paramList.add(param);
095          param = newParam(paramClass);
096        }
097      } else {
098        paramList.add(param);
099      }
100
101      map.put(param.getName(), paramList);
102    }
103    return new Parameters(map);
104  }
105
106  private Param<?> newParam(Class<Param<?>> paramClass) {
107    try {
108      return paramClass.newInstance();
109    } catch (Exception ex) {
110      throw new UnsupportedOperationException(
111        MessageFormat.format(
112          "Param class [{0}] does not have default constructor",
113          paramClass.getName()));
114    }
115  }
116
117  @Override
118  public ComponentScope getScope() {
119    return ComponentScope.PerRequest;
120  }
121
122  @Override
123  public Injectable getInjectable(ComponentContext componentContext, Context context, Type type) {
124    return (type.equals(Parameters.class)) ? this : null;
125  }
126}