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import org.dataloader.BatchLoader;
import org.dataloader.BatchLoaderEnvironment;
import org.dataloader.BatchLoaderWithContext;
import org.dataloader.CacheMap;
import org.dataloader.DataLoader;
import org.dataloader.DataLoaderOptions;
import org.dataloader.MappedBatchLoaderWithContext;
import org.dataloader.Try;
import org.dataloader.fixtures.SecurityCtx;
import org.dataloader.fixtures.User;
import org.dataloader.fixtures.UserManager;
import org.dataloader.stats.Statistics;
import org.dataloader.stats.ThreadLocalStatisticsCollector;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionStage;
import java.util.stream.Collectors;
import static java.lang.String.format;
@SuppressWarnings("ALL")
public class ReadmeExamples {
UserManager userManager = new UserManager();
public static void main(String[] args) {
ReadmeExamples examples = new ReadmeExamples();
examples.basicExample();
}
@SuppressWarnings({"Convert2Lambda", "Convert2MethodRef", "CodeBlock2Expr"})
void basicExample() {
BatchLoader<Long, User> lessEfficientUserBatchLoader = new BatchLoader<Long, User>() {
@Override
public CompletionStage<List<User>> load(List<Long> userIds) {
return CompletableFuture.supplyAsync(() -> {
//
// notice how it makes N calls to load by single user id out of the batch of N keys
//
return userIds.stream()
.map(id -> userManager.loadUserById(id))
.collect(Collectors.toList());
});
}
};
BatchLoader<Long, User> userBatchLoader = new BatchLoader<Long, User>() {
@Override
public CompletionStage<List<User>> load(List<Long> userIds) {
return CompletableFuture.supplyAsync(() -> {
return userManager.loadUsersById(userIds);
});
}
};
DataLoader<Long, User> userLoader = DataLoader.newDataLoader(userBatchLoader);
CompletionStage<User> load1 = userLoader.load(1L);
userLoader.load(1L)
.thenAccept(user -> {
System.out.println("user = " + user);
userLoader.load(user.getInvitedByID())
.thenAccept(invitedBy -> {
System.out.println("invitedBy = " + invitedBy);
});
});
userLoader.load(2L)
.thenAccept(user -> {
System.out.println("user = " + user);
userLoader.load(user.getInvitedByID())
.thenAccept(invitedBy -> {
System.out.println("invitedBy = " + invitedBy);
});
});
userLoader.dispatchAndJoin();
}
private void callContextExample() {
DataLoaderOptions options = DataLoaderOptions.newOptions()
.setBatchLoaderContextProvider(() -> SecurityCtx.getCallingUserCtx());
BatchLoaderWithContext<String, String> batchLoader = new BatchLoaderWithContext<String, String>() {
@Override
public CompletionStage<List<String>> load(List<String> keys, BatchLoaderEnvironment environment) {
SecurityCtx callCtx = environment.getContext();
return callDatabaseForResults(callCtx, keys);
}
};
DataLoader<String, String> loader = DataLoader.newDataLoader(batchLoader, options);
}
private void keyContextExample() {
DataLoaderOptions options = DataLoaderOptions.newOptions()
.setBatchLoaderContextProvider(() -> SecurityCtx.getCallingUserCtx());
BatchLoaderWithContext<String, String> batchLoader = new BatchLoaderWithContext<String, String>() {
@Override
public CompletionStage<List<String>> load(List<String> keys, BatchLoaderEnvironment environment) {
SecurityCtx callCtx = environment.getContext();
//
// this is the load context objects in map form by key
// in this case [ keyA : contextForA, keyB : contextForB ]
//
Map<Object, Object> keyContexts = environment.getKeyContexts();
//
// this is load context in list form
//
// in this case [ contextForA, contextForB ]
return callDatabaseForResults(callCtx, keys);
}
};
DataLoader<String, String> loader = DataLoader.newDataLoader(batchLoader, options);
loader.load("keyA", "contextForA");
loader.load("keyB", "contextForB");
}
private CompletionStage<List<String>> callDatabaseForResults(SecurityCtx callCtx, List<String> keys) {
return null;
}
private void mapBatchLoader() {
MappedBatchLoaderWithContext<Long, User> mapBatchLoader = new MappedBatchLoaderWithContext<Long, User>() {
@Override
public CompletionStage<Map<Long, User>> load(Set<Long> userIds, BatchLoaderEnvironment environment) {
SecurityCtx callCtx = environment.getContext();
return CompletableFuture.supplyAsync(() -> userManager.loadMapOfUsersByIds(callCtx, userIds));
}
};
DataLoader<Long, User> userLoader = DataLoader.newMappedDataLoader(mapBatchLoader);
// ...
}
private void tryExample() {
Try<String> tryS = Try.tryCall(() -> {
if (rollDice()) {
return "OK";
} else {
throw new RuntimeException("Bang");
}
});
if (tryS.isSuccess()) {
System.out.println("It work " + tryS.get());
} else {
System.out.println("It failed with exception : " + tryS.getThrowable());
}
}
private void tryBatcLoader() {
DataLoader<String, User> dataLoader = DataLoader.newDataLoaderWithTry(new BatchLoader<String, Try<User>>() {
@Override
public CompletionStage<List<Try<User>>> load(List<String> keys) {
return CompletableFuture.supplyAsync(() -> {
List<Try<User>> users = new ArrayList<>();
for (String key : keys) {
Try<User> userTry = loadUser(key);
users.add(userTry);
}
return users;
});
}
});
}
DataLoader<String, User> userDataLoader;
private void clearCacheOnError() {
userDataLoader.load("r2d2").whenComplete((user, throwable) -> {
if (throwable != null) {
userDataLoader.clear("r2dr");
throwable.printStackTrace();
} else {
processUser(user);
}
});
}
BatchLoader<String, User> userBatchLoader;
private void disableCache() {
DataLoader.newDataLoader(userBatchLoader, DataLoaderOptions.newOptions().setCachingEnabled(false));
userDataLoader.load("A");
userDataLoader.load("B");
userDataLoader.load("A");
userDataLoader.dispatch();
// will result in keys to the batch loader with [ "A", "B", "A" ]
}
class MyCustomCache implements CacheMap {
@Override
public boolean containsKey(Object key) {
return false;
}
@Override
public Object get(Object key) {
return null;
}
@Override
public CacheMap set(Object key, Object value) {
return null;
}
@Override
public CacheMap delete(Object key) {
return null;
}
@Override
public CacheMap clear() {
return null;
}
}
private void customCache() {
MyCustomCache customCache = new MyCustomCache();
DataLoaderOptions options = DataLoaderOptions.newOptions().setCacheMap(customCache);
DataLoader.newDataLoader(userBatchLoader, options);
}
private void processUser(User user) {
}
private Try<User> loadUser(String key) {
return null;
}
private boolean rollDice() {
return false;
}
private void statsExample() {
Statistics statistics = userDataLoader.getStatistics();
System.out.println(format("load : %d", statistics.getLoadCount()));
System.out.println(format("batch load: %d", statistics.getBatchLoadCount()));
System.out.println(format("cache hit: %d", statistics.getCacheHitCount()));
System.out.println(format("cache hit ratio: %d", statistics.getCacheHitRatio()));
}
private void statsConfigExample() {
DataLoaderOptions options = DataLoaderOptions.newOptions().setStatisticsCollector(() -> new ThreadLocalStatisticsCollector());
DataLoader<String, User> userDataLoader = DataLoader.newDataLoader(userBatchLoader, options);
}
}