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Added the list of call context objects into the environment
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‎README.md‎

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@@ -194,6 +194,36 @@ for the context object.
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The batch loading code will now receive this environment object and it can be used to get context perhaps allowing it
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to connect to other systems.
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You can also pass in context objects per load call. This will be captured and passed to the batch loader function.
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You can gain access to them as a map by key or as the original list of context objects.
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```java
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DataLoaderOptions options = DataLoaderOptions.newOptions()
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.setBatchLoaderContextProvider(() -> SecurityCtx.getCallingUserCtx());
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BatchLoaderWithContext<String, String> batchLoader = new BatchLoaderWithContext<String, String>() {
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@Override
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public CompletionStage<List<String>> load(List<String> keys, BatchLoaderEnvironment environment) {
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SecurityCtx callCtx = environment.getContext();
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//
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// this is the load context objects in map form by key
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// in this case [ keyA : contextForA, keyB : contextForB ]
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//
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Map<Object, Object> keyContexts = environment.getKeyContexts();
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//
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// this is load context in list form
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//
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// in this case [ contextForA, contextForB ]
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return callDatabaseForResults(callCtx, keys);
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}
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};
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DataLoader<String, String> loader = DataLoader.newDataLoader(batchLoader, options);
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loader.load("keyA", "contextForA");
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loader.load("keyB", "contextForB");
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```
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### Returning a Map of results from your batch loader
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Often there is not a 1:1 mapping of your batch loaded keys to the values returned.

‎src/main/java/org/dataloader/BatchLoaderEnvironment.java‎

Lines changed: 39 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -1,9 +1,12 @@
11
package org.dataloader;
22

3+
import java.util.ArrayList;
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import java.util.Collections;
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import java.util.HashMap;
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import java.util.List;
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import java.util.Map;
58

6-
import static org.dataloader.impl.Assertions.nonNull;
9+
import static java.util.Objects.nonNull;
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/**
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* This object is passed to a batch loader as calling context. It could contain security credentials
@@ -13,10 +16,12 @@ public class BatchLoaderEnvironment {
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private final Object context;
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private final Map<Object, Object> keyContexts;
19+
private final List<Object> keyContextsList;
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17-
private BatchLoaderEnvironment(Object context, Map<Object, Object> keyContexts) {
21+
private BatchLoaderEnvironment(Object context, List<Object> keyContextsList, Map<Object, Object> keyContexts) {
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this.context = context;
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this.keyContexts = keyContexts;
24+
this.keyContextsList = keyContextsList;
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}
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2227
/**
@@ -42,13 +47,25 @@ public Map<Object, Object> getKeyContexts() {
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return keyContexts;
4348
}
4449

50+
/**
51+
* Each call to {@link org.dataloader.DataLoader#load(Object, Object)} or
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* {@link org.dataloader.DataLoader#loadMany(java.util.List, java.util.List)} can be given
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* a context object when it is invoked. A list of them is present by this method.
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*
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* @return a list of key context objects in the order they where encountered
56+
*/
57+
public List<Object> getKeyContextsList() {
58+
return keyContextsList;
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}
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public static Builder newBatchLoaderEnvironment() {
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return new Builder();
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}
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public static class Builder {
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private Object context;
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private Map<Object, Object> keyContexts = Collections.emptyMap();
68+
private List<Object> keyContextsList = Collections.emptyList();
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5370
private Builder() {
5471

@@ -59,13 +76,30 @@ public Builder context(Object context) {
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return this;
6077
}
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62-
public Builder keyContexts(Map<Object, Object> keyContexts) {
63-
this.keyContexts = nonNull(keyContexts);
79+
public <K> Builder keyContexts(List<K> keys, List<Object> keyContexts) {
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nonNull(keys);
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nonNull(keyContexts);
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83+
Map<Object, Object> map = new HashMap<>();
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List<Object> list = new ArrayList<>();
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for (int i = 0; i < keys.size(); i++) {
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K key = keys.get(i);
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Object keyContext = null;
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if (i < keyContexts.size()) {
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keyContext = keyContexts.get(i);
90+
}
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if (keyContext != null) {
92+
map.put(key, keyContext);
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}
94+
list.add(keyContext);
95+
}
96+
this.keyContexts = map;
97+
this.keyContextsList = list;
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return this;
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}
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67101
public BatchLoaderEnvironment build() {
68-
return new BatchLoaderEnvironment(context, keyContexts);
102+
return new BatchLoaderEnvironment(context, keyContextsList, keyContexts);
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}
70104
}
71105
}

‎src/main/java/org/dataloader/DataLoaderHelper.java‎

Lines changed: 2 additions & 20 deletions
Original file line numberDiff line numberDiff line change
@@ -5,7 +5,6 @@
55

66
import java.util.ArrayList;
77
import java.util.Collection;
8-
import java.util.HashMap;
98
import java.util.LinkedHashSet;
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import java.util.List;
1110
import java.util.Map;
@@ -225,9 +224,8 @@ CompletableFuture<V> invokeLoaderImmediately(K key, Object keyContext) {
225224
CompletionStage<V> singleLoadCall;
226225
try {
227226
Object context = loaderOptions.getBatchLoaderContextProvider().getContext();
228-
Map<Object, Object> keyContextMap = mkKeyContextMap(keys, singletonList(keyContext));
229227
BatchLoaderEnvironment environment = BatchLoaderEnvironment.newBatchLoaderEnvironment()
230-
.context(context).keyContexts(keyContextMap).build();
228+
.context(context).keyContexts(keys, singletonList(keyContext)).build();
231229
if (isMapLoader()) {
232230
singleLoadCall = invokeMapBatchLoader(keys, environment).thenApply(list -> list.get(0));
233231
} else {
@@ -243,9 +241,8 @@ CompletionStage<List<V>> invokeLoader(List<K> keys, List<Object> keyContexts) {
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CompletionStage<List<V>> batchLoad;
244242
try {
245243
Object context = loaderOptions.getBatchLoaderContextProvider().getContext();
246-
Map<Object, Object> keyContextMap = mkKeyContextMap(keys, keyContexts);
247244
BatchLoaderEnvironment environment = BatchLoaderEnvironment.newBatchLoaderEnvironment()
248-
.context(context).keyContexts(keyContextMap).build();
245+
.context(context).keyContexts(keys, keyContexts).build();
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if (isMapLoader()) {
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batchLoad = invokeMapBatchLoader(keys, environment);
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} else {
@@ -297,21 +294,6 @@ private boolean isMapLoader() {
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return batchLoadFunction instanceof MappedBatchLoader || batchLoadFunction instanceof MappedBatchLoaderWithContext;
298295
}
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300-
private Map<Object, Object> mkKeyContextMap(List<K> keys, List<Object> keyContexts) {
301-
Map<Object, Object> map = new HashMap<>();
302-
for (int i = 0; i < keys.size(); i++) {
303-
K key = keys.get(i);
304-
Object keyContext = null;
305-
if (i < keyContexts.size()) {
306-
keyContext = keyContexts.get(i);
307-
}
308-
if (keyContext != null) {
309-
map.put(key, keyContext);
310-
}
311-
}
312-
return map;
313-
}
314-
315297
int dispatchDepth() {
316298
synchronized (dataLoader) {
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return loaderQueue.size();

‎src/test/java/ReadmeExamples.java‎

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Original file line numberDiff line numberDiff line change
@@ -99,6 +99,32 @@ public CompletionStage<List<String>> load(List<String> keys, BatchLoaderEnvironm
9999
DataLoader<String, String> loader = DataLoader.newDataLoader(batchLoader, options);
100100
}
101101

102+
private void keyContextExample() {
103+
DataLoaderOptions options = DataLoaderOptions.newOptions()
104+
.setBatchLoaderContextProvider(() -> SecurityCtx.getCallingUserCtx());
105+
106+
BatchLoaderWithContext<String, String> batchLoader = new BatchLoaderWithContext<String, String>() {
107+
@Override
108+
public CompletionStage<List<String>> load(List<String> keys, BatchLoaderEnvironment environment) {
109+
SecurityCtx callCtx = environment.getContext();
110+
//
111+
// this is the load context objects in map form by key
112+
// in this case [ keyA : contextForA, keyB : contextForB ]
113+
//
114+
Map<Object, Object> keyContexts = environment.getKeyContexts();
115+
//
116+
// this is load context in list form
117+
//
118+
// in this case [ contextForA, contextForB ]
119+
return callDatabaseForResults(callCtx, keys);
120+
}
121+
};
122+
123+
DataLoader<String, String> loader = DataLoader.newDataLoader(batchLoader, options);
124+
loader.load("keyA", "contextForA");
125+
loader.load("keyB", "contextForB");
126+
}
127+
102128
private CompletionStage<List<String>> callDatabaseForResults(SecurityCtx callCtx, List<String> keys) {
103129
return null;
104130
}

‎src/test/java/org/dataloader/DataLoaderBatchLoaderEnvironmentTest.java‎

Lines changed: 27 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -7,6 +7,7 @@
77
import java.util.List;
88
import java.util.Map;
99
import java.util.concurrent.CompletableFuture;
10+
import java.util.concurrent.atomic.AtomicInteger;
1011
import java.util.stream.Collectors;
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1213
import static java.util.Arrays.asList;
@@ -21,10 +22,13 @@ public class DataLoaderBatchLoaderEnvironmentTest {
2122

2223
private BatchLoaderWithContext<String, String> contextBatchLoader() {
2324
return (keys, environment) -> {
25+
AtomicInteger index = new AtomicInteger(0);
2426
List<String> list = keys.stream().map(k -> {
27+
int i = index.getAndIncrement();
2528
Object context = environment.getContext();
26-
Object keyContext = environment.getKeyContexts().get(k);
27-
return k + "-" + context + "-" + keyContext;
29+
Object keyContextM = environment.getKeyContexts().get(k);
30+
Object keyContextL = environment.getKeyContextsList().get(i);
31+
return k + "-" + context + "-m:" + keyContextM + "-l:" + keyContextL;
2832
}).collect(Collectors.toList());
2933
return CompletableFuture.completedFuture(list);
3034
};
@@ -63,7 +67,7 @@ public void key_contexts_are_passed_to_batch_loader_function() throws Exception
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6468
List<String> results = loader.dispatchAndJoin();
6569

66-
assertThat(results, equalTo(asList("A-ctx-aCtx", "B-ctx-bCtx", "C-ctx-cCtx", "D-ctx-dCtx")));
70+
assertThat(results, equalTo(asList("A-ctx-m:aCtx-l:aCtx", "B-ctx-m:bCtx-l:bCtx", "C-ctx-m:cCtx-l:cCtx", "D-ctx-m:dCtx-l:dCtx")));
6771
}
6872

6973
@Test
@@ -81,7 +85,7 @@ public void key_contexts_are_passed_to_batch_loader_function_when_batching_disab
8185
List<String> results = new ArrayList<>(asList(aLoad.join(), bLoad.join()));
8286
results.addAll(canDLoad.join());
8387

84-
assertThat(results, equalTo(asList("A-ctx-aCtx", "B-ctx-bCtx", "C-ctx-cCtx", "D-ctx-dCtx")));
88+
assertThat(results, equalTo(asList("A-ctx-m:aCtx-l:aCtx", "B-ctx-m:bCtx-l:bCtx", "C-ctx-m:cCtx-l:cCtx", "D-ctx-m:dCtx-l:dCtx")));
8589
}
8690

8791
@Test
@@ -97,7 +101,7 @@ public void missing_key_contexts_are_passed_to_batch_loader_function() throws Ex
97101

98102
List<String> results = loader.dispatchAndJoin();
99103

100-
assertThat(results, equalTo(asList("A-ctx-aCtx", "B-ctx-null", "C-ctx-cCtx", "D-ctx-null")));
104+
assertThat(results, equalTo(asList("A-ctx-m:aCtx-l:aCtx", "B-ctx-m:null-l:null", "C-ctx-m:cCtx-l:cCtx", "D-ctx-m:null-l:null")));
101105
}
102106

103107
@Test
@@ -158,4 +162,22 @@ public void null_is_passed_as_context_to_map_loader_if_you_do_nothing() throws E
158162

159163
assertThat(results, equalTo(asList("A-null", "B-null", "C-null", "D-null")));
160164
}
165+
166+
@Test
167+
public void mmap_semantics_apply_to_batch_loader_context() throws Exception {
168+
BatchLoaderWithContext<String, String> batchLoader = contextBatchLoader();
169+
DataLoaderOptions options = DataLoaderOptions.newOptions()
170+
.setBatchLoaderContextProvider(() -> "ctx")
171+
.setCachingEnabled(false);
172+
DataLoader<String, String> loader = DataLoader.newDataLoader(batchLoader, options);
173+
174+
loader.load("A", "aCtx");
175+
loader.load("B", "bCtx");
176+
loader.load("A", "overridesCtx");
177+
178+
List<String> results = loader.dispatchAndJoin();
179+
180+
assertThat(results, equalTo(asList("A-ctx-m:overridesCtx-l:aCtx", "B-ctx-m:bCtx-l:bCtx", "A-ctx-m:overridesCtx-l:overridesCtx")));
181+
}
182+
161183
}

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