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Java example source code file (ExclusionStrategyFunctionalTest.java)

This example Java source code file (ExclusionStrategyFunctionalTest.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

annotation, exception, exclusionstrategy, exclusionstrategyfunctionaltest, foo, gson, gsonbuilder, jsonobject, jsonprimitive, myexclusionstrategy, override, sampleobjectfortest, string, target, testcase

The ExclusionStrategyFunctionalTest.java Java example source code

/*
 * Copyright (C) 2008 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.functional;

import com.google.gson.ExclusionStrategy;
import com.google.gson.FieldAttributes;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonObject;
import com.google.gson.JsonPrimitive;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import junit.framework.TestCase;

/**
 * Performs some functional tests when Gson is instantiated with some common user defined
 * {@link ExclusionStrategy} objects.
 *
 * @author Inderjeet Singh
 * @author Joel Leitch
 */
public class ExclusionStrategyFunctionalTest extends TestCase {
  private static final ExclusionStrategy EXCLUDE_SAMPLE_OBJECT_FOR_TEST = new ExclusionStrategy() {
    @Override public boolean shouldSkipField(FieldAttributes f) {
      return false;
    }
    @Override public boolean shouldSkipClass(Class<?> clazz) {
      return clazz == SampleObjectForTest.class;
    }
  };

  private SampleObjectForTest src;

  @Override
  protected void setUp() throws Exception {
    super.setUp();
    src = new SampleObjectForTest();
  }

  public void testExclusionStrategySerialization() throws Exception {
    Gson gson = createGson(new MyExclusionStrategy(String.class), true);
    String json = gson.toJson(src);
    assertFalse(json.contains("\"stringField\""));
    assertFalse(json.contains("\"annotatedField\""));
    assertTrue(json.contains("\"longField\""));
  }

  public void testExclusionStrategySerializationDoesNotImpactDeserialization() {
    String json = "{\"annotatedField\":1,\"stringField\":\"x\",\"longField\":2}";
    Gson gson = createGson(new MyExclusionStrategy(String.class), true);
    SampleObjectForTest value = gson.fromJson(json, SampleObjectForTest.class);
    assertEquals(1, value.annotatedField);
    assertEquals("x", value.stringField);
    assertEquals(2, value.longField);
  }

  public void testExclusionStrategyDeserialization() throws Exception {
    Gson gson = createGson(new MyExclusionStrategy(String.class), false);
    JsonObject json = new JsonObject();
    json.add("annotatedField", new JsonPrimitive(src.annotatedField + 5));
    json.add("stringField", new JsonPrimitive(src.stringField + "blah,blah"));
    json.add("longField", new JsonPrimitive(1212311L));

    SampleObjectForTest target = gson.fromJson(json, SampleObjectForTest.class);
    assertEquals(1212311L, target.longField);

    // assert excluded fields are set to the defaults
    assertEquals(src.annotatedField, target.annotatedField);
    assertEquals(src.stringField, target.stringField);
  }

  public void testExclusionStrategySerializationDoesNotImpactSerialization() throws Exception {
    Gson gson = createGson(new MyExclusionStrategy(String.class), false);
    String json = gson.toJson(src);
    assertTrue(json.contains("\"stringField\""));
    assertTrue(json.contains("\"annotatedField\""));
    assertTrue(json.contains("\"longField\""));
  }

  public void testExclusionStrategyWithMode() throws Exception {
    SampleObjectForTest testObj = new SampleObjectForTest(
        src.annotatedField + 5, src.stringField + "blah,blah",
        src.longField + 655L);

    Gson gson = createGson(new MyExclusionStrategy(String.class), false);
    JsonObject json = gson.toJsonTree(testObj).getAsJsonObject();
    assertEquals(testObj.annotatedField, json.get("annotatedField").getAsInt());
    assertEquals(testObj.stringField, json.get("stringField").getAsString());
    assertEquals(testObj.longField, json.get("longField").getAsLong());

    SampleObjectForTest target = gson.fromJson(json, SampleObjectForTest.class);
    assertEquals(testObj.longField, target.longField);

    // assert excluded fields are set to the defaults
    assertEquals(src.annotatedField, target.annotatedField);
    assertEquals(src.stringField, target.stringField);
  }

  public void testExcludeTopLevelClassSerialization() {
    Gson gson = new GsonBuilder()
        .addSerializationExclusionStrategy(EXCLUDE_SAMPLE_OBJECT_FOR_TEST)
        .create();
    assertEquals("null", gson.toJson(new SampleObjectForTest(), SampleObjectForTest.class));
  }

  public void testExcludeTopLevelClassSerializationDoesNotImpactDeserialization() {
    Gson gson = new GsonBuilder()
        .addSerializationExclusionStrategy(EXCLUDE_SAMPLE_OBJECT_FOR_TEST)
        .create();
    String json = "{\"annotatedField\":1,\"stringField\":\"x\",\"longField\":2}";
    SampleObjectForTest value = gson.fromJson(json, SampleObjectForTest.class);
    assertEquals(1, value.annotatedField);
    assertEquals("x", value.stringField);
    assertEquals(2, value.longField);
  }

  public void testExcludeTopLevelClassDeserialization() {
    Gson gson = new GsonBuilder()
        .addDeserializationExclusionStrategy(EXCLUDE_SAMPLE_OBJECT_FOR_TEST)
        .create();
    String json = "{\"annotatedField\":1,\"stringField\":\"x\",\"longField\":2}";
    SampleObjectForTest value = gson.fromJson(json, SampleObjectForTest.class);
    assertNull(value);
  }

  public void testExcludeTopLevelClassDeserializationDoesNotImpactSerialization() {
    Gson gson = new GsonBuilder()
        .addDeserializationExclusionStrategy(EXCLUDE_SAMPLE_OBJECT_FOR_TEST)
        .create();
    String json = gson.toJson(new SampleObjectForTest(), SampleObjectForTest.class);
    assertTrue(json.contains("\"stringField\""));
    assertTrue(json.contains("\"annotatedField\""));
    assertTrue(json.contains("\"longField\""));
  }

  private static Gson createGson(ExclusionStrategy exclusionStrategy, boolean serialization) {
    GsonBuilder gsonBuilder = new GsonBuilder();
    if (serialization) {
      gsonBuilder.addSerializationExclusionStrategy(exclusionStrategy);
    } else {
      gsonBuilder.addDeserializationExclusionStrategy(exclusionStrategy);
    }
    return gsonBuilder
        .serializeNulls()
        .create();
  }

  @Retention(RetentionPolicy.RUNTIME)
  @Target({ElementType.FIELD})
  private static @interface Foo {
    // Field tag only annotation
  }

  private static class SampleObjectForTest {
    @Foo
    private final int annotatedField;
    private final String stringField;
    private final long longField;

    public SampleObjectForTest() {
      this(5, "someDefaultValue", 12345L);
    }

    public SampleObjectForTest(int annotatedField, String stringField, long longField) {
      this.annotatedField = annotatedField;
      this.stringField = stringField;
      this.longField = longField;
    }
  }

  private static final class MyExclusionStrategy implements ExclusionStrategy {
    private final Class<?> typeToSkip;

    private MyExclusionStrategy(Class<?> typeToSkip) {
      this.typeToSkip = typeToSkip;
    }

    @Override public boolean shouldSkipClass(Class<?> clazz) {
      return (clazz == typeToSkip);
    }

    @Override public boolean shouldSkipField(FieldAttributes f) {
      return f.getAnnotation(Foo.class) != null;
    }
  }
}

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