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Java example source code file (InterceptorTest.java)

This example Java source code file (InterceptorTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

address, gson, gsonbuilder, interceptorfactory, ioexception, jsonpostdeserializer, jsonsyntaxexception, override, reflection, string, suppresswarnings, typeadapter, typetoken, user, usergroup, util

The InterceptorTest.java Java example source code

/*
 * Copyright (C) 2012 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.google.gson.interceptors;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonParseException;
import com.google.gson.JsonSyntaxException;
import com.google.gson.TypeAdapter;
import com.google.gson.reflect.TypeToken;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonWriter;
import java.io.IOException;
import java.lang.reflect.Type;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import junit.framework.TestCase;

/**
 * Unit tests for {@link Intercept} and {@link JsonPostDeserializer}.
 *
 * @author Inderjeet Singh
 */
public final class InterceptorTest extends TestCase {

  private Gson gson;

  @Override
  public void setUp() throws Exception {
    super.setUp();
    this.gson = new GsonBuilder()
        .registerTypeAdapterFactory(new InterceptorFactory())
        .enableComplexMapKeySerialization()
        .create();
  }

  public void testExceptionsPropagated() {
    try {
      gson.fromJson("{}", User.class);
      fail();
    } catch (JsonParseException expected) {}
  }

  public void testTopLevelClass() {
    User user = gson.fromJson("{name:'bob',password:'pwd'}", User.class);
    assertEquals(User.DEFAULT_EMAIL, user.email);
  }

  public void testList() {
    List<User> list = gson.fromJson("[{name:'bob',password:'pwd'}]", new TypeToken>(){}.getType());
    User user = list.get(0);
    assertEquals(User.DEFAULT_EMAIL, user.email);
  }

  public void testCollection() {
    Collection<User> list = gson.fromJson("[{name:'bob',password:'pwd'}]", new TypeToken>(){}.getType());
    User user = list.iterator().next();
    assertEquals(User.DEFAULT_EMAIL, user.email);
  }

  public void testMapKeyAndValues() {
    Type mapType = new TypeToken<Map(){}.getType();
    try {
      gson.fromJson("[[{name:'bob',password:'pwd'},{}]]", mapType);
      fail();
    } catch (JsonSyntaxException expected) {}
    Map<User, Address> map = gson.fromJson("[[{name:'bob',password:'pwd'},{city:'Mountain View',state:'CA',zip:'94043'}]]",
        mapType);
    Entry<User, Address> entry = map.entrySet().iterator().next();
    assertEquals(User.DEFAULT_EMAIL, entry.getKey().email);
    assertEquals(Address.DEFAULT_FIRST_LINE, entry.getValue().firstLine);
  }

  public void testField() {
    UserGroup userGroup = gson.fromJson("{user:{name:'bob',password:'pwd'}}", UserGroup.class);
    assertEquals(User.DEFAULT_EMAIL, userGroup.user.email);
  }

  public void testCustomTypeAdapter() {
    Gson gson = new GsonBuilder()
        .registerTypeAdapter(User.class, new TypeAdapter<User>() {
          @Override public void write(JsonWriter out, User value) throws IOException {
            throw new UnsupportedOperationException();
          }

          @Override public User read(JsonReader in) throws IOException {
            in.beginObject();
            in.nextName();
            String name = in.nextString();
            in.nextName();
            String password = in.nextString();
            in.endObject();
            return new User(name, password);
          }
        })
        .registerTypeAdapterFactory(new InterceptorFactory())
        .create();
    UserGroup userGroup = gson.fromJson("{user:{name:'bob',password:'pwd'}}", UserGroup.class);
    assertEquals(User.DEFAULT_EMAIL, userGroup.user.email);
  }

  public void testDirectInvocationOfTypeAdapter() throws Exception {
    TypeAdapter<UserGroup> adapter = gson.getAdapter(UserGroup.class);
    UserGroup userGroup = adapter.fromJson("{\"user\":{\"name\":\"bob\",\"password\":\"pwd\"}}");
    assertEquals(User.DEFAULT_EMAIL, userGroup.user.email);
  }

  @SuppressWarnings("unused")
  private static final class UserGroup {
    User user;
    String city;
  }

  @Intercept(postDeserialize = UserValidator.class)
  @SuppressWarnings("unused")
  private static final class User {
    static final String DEFAULT_EMAIL = "invalid@invalid.com";
    String name;
    String password;
    String email;
    Address address;
    public User(String name, String password) {
      this.name = name;
      this.password = password;
    }
  }

  public static final class UserValidator implements JsonPostDeserializer<User> {
    public void postDeserialize(User user) {
      if (user.name == null || user.password == null) {
        throw new JsonSyntaxException("name and password are required fields.");
      }
      if (user.email == null) user.email = User.DEFAULT_EMAIL;
    }
  }

  @Intercept(postDeserialize = AddressValidator.class)
  @SuppressWarnings("unused")
  private static final class Address {
    static final String DEFAULT_FIRST_LINE = "unknown";
    String firstLine;
    String secondLine;
    String city;
    String state;
    String zip;
  }

  public static final class AddressValidator implements JsonPostDeserializer<Address> {
    public void postDeserialize(Address address) {
      if (address.city == null || address.state == null || address.zip == null) {
        throw new JsonSyntaxException("Address city, state and zip are required fields.");
      }
      if (address.firstLine == null) address.firstLine = Address.DEFAULT_FIRST_LINE;
    }
  }
}

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