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;
029import org.apache.hadoop.util.StringUtils;
030
031import javax.ws.rs.core.Context;
032import javax.ws.rs.core.MultivaluedMap;
033import java.lang.reflect.Type;
034import java.text.MessageFormat;
035import java.util.HashMap;
036import java.util.List;
037import java.util.Map;
038
039/**
040 * Jersey provider that parses the request parameters based on the
041 * given parameter definition. 
042 */
043@InterfaceAudience.Private
044public class ParametersProvider
045  extends AbstractHttpContextInjectable<Parameters>
046  implements InjectableProvider<Context, Type> {
047
048  private String driverParam;
049  private Class<? extends Enum> enumClass;
050  private Map<Enum, Class<Param<?>>[]> paramsDef;
051
052  public ParametersProvider(String driverParam, Class<? extends Enum> enumClass,
053                            Map<Enum, Class<Param<?>>[]> paramsDef) {
054    this.driverParam = driverParam;
055    this.enumClass = enumClass;
056    this.paramsDef = paramsDef;
057  }
058
059  @Override
060  @SuppressWarnings("unchecked")
061  public Parameters getValue(HttpContext httpContext) {
062    Map<String, List<Param<?>>> map = new HashMap<String, List<Param<?>>>();
063    Map<String, List<String>> queryString =
064      httpContext.getRequest().getQueryParameters();
065    String str = ((MultivaluedMap<String, String>) queryString).
066        getFirst(driverParam);
067    if (str == null) {
068      throw new IllegalArgumentException(
069        MessageFormat.format("Missing Operation parameter [{0}]",
070                             driverParam));
071    }
072    Enum op;
073    try {
074      op = Enum.valueOf(enumClass, StringUtils.toUpperCase(str));
075    } catch (IllegalArgumentException ex) {
076      throw new IllegalArgumentException(
077        MessageFormat.format("Invalid Operation [{0}]", str));
078    }
079    if (!paramsDef.containsKey(op)) {
080      throw new IllegalArgumentException(
081        MessageFormat.format("Unsupported Operation [{0}]", op));
082    }
083    for (Class<Param<?>> paramClass : paramsDef.get(op)) {
084      Param<?> param = newParam(paramClass);
085      List<Param<?>> paramList = Lists.newArrayList();
086      List<String> ps = queryString.get(param.getName());
087      if (ps != null) {
088        for (String p : ps) {
089          try {
090            param.parseParam(p);
091          }
092          catch (Exception ex) {
093            throw new IllegalArgumentException(ex.toString(), ex);
094          }
095          paramList.add(param);
096          param = newParam(paramClass);
097        }
098      } else {
099        paramList.add(param);
100      }
101
102      map.put(param.getName(), paramList);
103    }
104    return new Parameters(map);
105  }
106
107  private Param<?> newParam(Class<Param<?>> paramClass) {
108    try {
109      return paramClass.newInstance();
110    } catch (Exception ex) {
111      throw new UnsupportedOperationException(
112        MessageFormat.format(
113          "Param class [{0}] does not have default constructor",
114          paramClass.getName()));
115    }
116  }
117
118  @Override
119  public ComponentScope getScope() {
120    return ComponentScope.PerRequest;
121  }
122
123  @Override
124  public Injectable getInjectable(ComponentContext componentContext, Context context, Type type) {
125    return (type.equals(Parameters.class)) ? this : null;
126  }
127}