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Java example source code file (TestScope.java)

This example Java source code file (TestScope.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, hashmap, key, object, provider, retention, scopeannotation, scoped, suppresswarnings, testscope, util

The TestScope.java Java example source code

 * Copyright (C) 2007 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,
 * See the License for the specific language governing permissions and
 * limitations under the License.

package com.google.inject.throwingproviders;

import static java.lang.annotation.RetentionPolicy.RUNTIME;

import com.google.inject.Key;
import com.google.inject.Provider;
import com.google.inject.Scope;
import com.google.inject.ScopeAnnotation;

import java.lang.annotation.Retention;
import java.util.HashMap;
import java.util.Map;

 * A simple scope that can be explicitly reset.
 * @author jmourits@google.com (Jerome Mourits)
class TestScope implements Scope {

  @Retention(RUNTIME) @ScopeAnnotation
  public @interface Scoped { }

  private Map<Key, Object> inScopeObjectsMap = new HashMap();

  public <T> Provider scope(
      final Key<T> key, final Provider provider) {
    return new Provider<T>() {
      public T get() {
        T t = (T) inScopeObjectsMap.get(key);
        if (t == null) {
          t = provider.get();
          inScopeObjectsMap.put(key, t);
        return t;

  public void beginNewScope() {
    inScopeObjectsMap = new HashMap<Key, Object>();

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