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Add missing snippets to Datastore Transaction, add snippets to Transaction javadoc (#1270)
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Lines changed: 268 additions & 6 deletions

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‎google-cloud-datastore/src/main/java/com/google/cloud/datastore/Transaction.java‎

Lines changed: 64 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -63,6 +63,15 @@ interface Response {
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* to fail if entity was changed by others after it was seen by this transaction) but any
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* write changes in this transaction will not be reflected by the returned entity.
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*
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* <p>Example of getting an entity for a given key.
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* <pre> {@code
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* String keyName = "my_key_name";
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* Key key = datastore.newKeyFactory().kind("MyKind").newKey(keyName);
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* Entity entity = transaction.get(key);
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* transaction.commit();
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* // Do something with the entity
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* }</pre>
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*
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* @throws DatastoreException upon failure or if no longer active
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*/
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@Override
@@ -74,6 +83,23 @@ interface Response {
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* to fail if any of the entities was changed by others after they were seen by this transaction)
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* but any write changes in this transaction will not be reflected by the returned entities.
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*
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* <p>Example of getting entities for several keys.
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* <pre> {@code
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* String firstKeyName = "my_first_key_name";
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* String secondKeyName = "my_second_key_name";
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* KeyFactory keyFactory = datastore.newKeyFactory().kind("MyKind");
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* Key firstKey = keyFactory.newKey(firstKeyName);
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* Key secondKey = keyFactory.newKey(secondKeyName);
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* Iterator<Entity> entitiesIterator = transaction.get(firstKey, secondKey);
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* List<Entity> entities = Lists.newArrayList();
95+
* while (entitiesIterator.hasNext()) {
96+
* Entity entity = entitiesIterator.next();
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* // do something with the entity
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* entities.add(entity);
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* }
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* transaction.commit();
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* }</pre>
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*
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* @throws DatastoreException upon failure or if no longer active
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*/
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@Override
@@ -85,6 +111,20 @@ interface Response {
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* to fail if any of the entities was changed by others after they were seen by this transaction)
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* but any write changes in this transaction will not be reflected by the returned entities.
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*
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* <p>Example of fetching a list of entities for several keys.
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* <pre> {@code
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* String firstKeyName = "my_first_key_name";
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* String secondKeyName = "my_second_key_name";
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* KeyFactory keyFactory = datastore.newKeyFactory().kind("MyKind");
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* Key firstKey = keyFactory.newKey(firstKeyName);
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* Key secondKey = keyFactory.newKey(secondKeyName);
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* List<Entity> entities = transaction.fetch(firstKey, secondKey);
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* for (Entity entity : entities) {
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* // do something with the entity
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* }
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* transaction.commit();
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* }</pre>
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*
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* @throws DatastoreException upon failure or if no longer active
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*/
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@Override
@@ -97,6 +137,26 @@ interface Response {
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* query was performed) but any write changes in this transaction will not be reflected by
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* the result.
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*
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* <p>Example of running a query to find all entities with an ancestor.
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* <pre> {@code
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* String parentKeyName = "my_parent_key_name";
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* KeyFactory keyFactory = datastore.newKeyFactory().kind("ParentKind");
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* Key parentKey = keyFactory.newKey(parentKeyName);
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* // Build a query
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* Query<Entity> query = Query.entityQueryBuilder()
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* .kind("MyKind")
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* .filter(PropertyFilter.hasAncestor(parentKey))
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* .build();
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* QueryResults<Entity> results = transaction.run(query);
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* List<Entity> entities = Lists.newArrayList();
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* while (results.hasNext()) {
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* Entity result = results.next();
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* // do something with result
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* entities.add(result);
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* }
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* transaction.commit();
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* }</pre>
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*
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* @throws DatastoreException upon failure or if no longer active
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*/
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@Override
@@ -108,9 +168,10 @@ interface Response {
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* <p>Example of committing a transaction.
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* <pre> {@code
110170
* // create an entity
111-
* KeyFactory keyFactory = datastore.newKeyFactory().kind("someKind");
171+
* KeyFactory keyFactory = datastore.newKeyFactory().kind("MyKind");
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* Key key = datastore.allocateId(keyFactory.newKey());
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* Entity entity = Entity.builder(key).set("description", "commit()").build();
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*
114175
* // add the entity and commit
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* try {
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* transaction.put(entity);
@@ -130,7 +191,7 @@ interface Response {
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* <p>Example of rolling back a transaction.
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* <pre> {@code
132193
* // create an entity
133-
* KeyFactory keyFactory = datastore.newKeyFactory().kind("someKind");
194+
* KeyFactory keyFactory = datastore.newKeyFactory().kind("MyKind");
134195
* Key key = datastore.allocateId(keyFactory.newKey());
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* Entity entity = Entity.builder(key).set("description", "rollback()").build();
136197
*
@@ -150,7 +211,7 @@ interface Response {
150211
* <p>Example of verifying if a transaction is active.
151212
* <pre> {@code
152213
* // create an entity
153-
* KeyFactory keyFactory = datastore.newKeyFactory().kind("someKind");
214+
* KeyFactory keyFactory = datastore.newKeyFactory().kind("MyKind");
154215
* Key key = datastore.allocateId(keyFactory.newKey());
155216
* Entity entity = Entity.builder(key).set("description", "active()").build();
156217
* // calling transaction.active() now would return true

‎google-cloud-examples/src/main/java/com/google/cloud/examples/datastore/snippets/TransactionSnippets.java‎

Lines changed: 101 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -22,13 +22,20 @@
2222

2323
package com.google.cloud.examples.datastore.snippets;
2424

25+
import com.google.api.client.util.Lists;
2526
import com.google.cloud.datastore.Datastore;
2627
import com.google.cloud.datastore.DatastoreException;
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import com.google.cloud.datastore.Entity;
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import com.google.cloud.datastore.Key;
2930
import com.google.cloud.datastore.KeyFactory;
31+
import com.google.cloud.datastore.Query;
32+
import com.google.cloud.datastore.QueryResults;
33+
import com.google.cloud.datastore.StructuredQuery.PropertyFilter;
3034
import com.google.cloud.datastore.Transaction;
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36+
import java.util.Iterator;
37+
import java.util.List;
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3239
/**
3340
* This class contains a number of snippets for the {@link Transaction} interface.
3441
*/
@@ -40,6 +47,95 @@ public TransactionSnippets(Transaction transaction) {
4047
this.transaction = transaction;
4148
}
4249

50+
/**
51+
* Example of getting an entity for a given key.
52+
*/
53+
// [TARGET get(Key)]
54+
// [VARIABLE "my_key_name"]
55+
public Entity get(String keyName) {
56+
Datastore datastore = transaction.datastore();
57+
// [START get]
58+
Key key = datastore.newKeyFactory().kind("MyKind").newKey(keyName);
59+
Entity entity = transaction.get(key);
60+
transaction.commit();
61+
// Do something with the entity
62+
// [END get]
63+
return entity;
64+
}
65+
66+
/**
67+
* Example of getting entities for several keys.
68+
*/
69+
// [TARGET get(Key...)]
70+
// [VARIABLE "my_first_key_name"]
71+
// [VARIABLE "my_second_key_name"]
72+
public List<Entity> getMultiple(String firstKeyName, String secondKeyName) {
73+
Datastore datastore = transaction.datastore();
74+
// TODO change so that it's not necessary to hold the entities in a list for integration testing
75+
// [START getMultiple]
76+
KeyFactory keyFactory = datastore.newKeyFactory().kind("MyKind");
77+
Key firstKey = keyFactory.newKey(firstKeyName);
78+
Key secondKey = keyFactory.newKey(secondKeyName);
79+
Iterator<Entity> entitiesIterator = transaction.get(firstKey, secondKey);
80+
List<Entity> entities = Lists.newArrayList();
81+
while (entitiesIterator.hasNext()) {
82+
Entity entity = entitiesIterator.next();
83+
// do something with the entity
84+
entities.add(entity);
85+
}
86+
transaction.commit();
87+
// [END getMultiple]
88+
return entities;
89+
}
90+
91+
/**
92+
* Example of fetching a list of entities for several keys.
93+
*/
94+
// [TARGET fetch(Key...)]
95+
// [VARIABLE "my_first_key_name"]
96+
// [VARIABLE "my_second_key_name"]
97+
public List<Entity> fetchEntitiesWithKeys(String firstKeyName, String secondKeyName) {
98+
Datastore datastore = transaction.datastore();
99+
// [START fetchEntitiesWithKeys]
100+
KeyFactory keyFactory = datastore.newKeyFactory().kind("MyKind");
101+
Key firstKey = keyFactory.newKey(firstKeyName);
102+
Key secondKey = keyFactory.newKey(secondKeyName);
103+
List<Entity> entities = transaction.fetch(firstKey, secondKey);
104+
for (Entity entity : entities) {
105+
// do something with the entity
106+
}
107+
transaction.commit();
108+
// [END fetchEntitiesWithKeys]
109+
return entities;
110+
}
111+
112+
/**
113+
* Example of running a query to find all entities with an ancestor.
114+
*/
115+
// [TARGET run(Query)]
116+
// [VARIABLE "my_parent_key_name"]
117+
public List<Entity> run(String parentKeyName) {
118+
Datastore datastore = transaction.datastore();
119+
// [START run]
120+
KeyFactory keyFactory = datastore.newKeyFactory().kind("ParentKind");
121+
Key parentKey = keyFactory.newKey(parentKeyName);
122+
// Build a query
123+
Query<Entity> query = Query.entityQueryBuilder()
124+
.kind("MyKind")
125+
.filter(PropertyFilter.hasAncestor(parentKey))
126+
.build();
127+
QueryResults<Entity> results = transaction.run(query);
128+
List<Entity> entities = Lists.newArrayList();
129+
while (results.hasNext()) {
130+
Entity result = results.next();
131+
// do something with result
132+
entities.add(result);
133+
}
134+
transaction.commit();
135+
// [END run]
136+
return entities;
137+
}
138+
43139
/**
44140
* Example of committing a transaction.
45141
*/
@@ -48,9 +144,10 @@ public Key commit() {
48144
Datastore datastore = transaction.datastore();
49145
// [START commit]
50146
// create an entity
51-
KeyFactory keyFactory = datastore.newKeyFactory().kind("someKind");
147+
KeyFactory keyFactory = datastore.newKeyFactory().kind("MyKind");
52148
Key key = datastore.allocateId(keyFactory.newKey());
53149
Entity entity = Entity.builder(key).set("description", "commit()").build();
150+
54151
// add the entity and commit
55152
try {
56153
transaction.put(entity);
@@ -59,6 +156,7 @@ public Key commit() {
59156
// handle exception
60157
}
61158
// [END commit]
159+
62160
return key;
63161
}
64162

@@ -70,7 +168,7 @@ public Key rollback() {
70168
Datastore datastore = transaction.datastore();
71169
// [START rollback]
72170
// create an entity
73-
KeyFactory keyFactory = datastore.newKeyFactory().kind("someKind");
171+
KeyFactory keyFactory = datastore.newKeyFactory().kind("MyKind");
74172
Key key = datastore.allocateId(keyFactory.newKey());
75173
Entity entity = Entity.builder(key).set("description", "rollback()").build();
76174

@@ -90,7 +188,7 @@ public Key active() {
90188
Datastore datastore = transaction.datastore();
91189
// [START active]
92190
// create an entity
93-
KeyFactory keyFactory = datastore.newKeyFactory().kind("someKind");
191+
KeyFactory keyFactory = datastore.newKeyFactory().kind("MyKind");
94192
Key key = datastore.allocateId(keyFactory.newKey());
95193
Entity entity = Entity.builder(key).set("description", "active()").build();
96194
// calling transaction.active() now would return true

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