feat: support conditional policies

google-cloud-core/pom.xml

@@ -27,6 +27,10 @@
       <groupId>com.google.api</groupId>
       <artifactId>gax</artifactId>
     </dependency>
+    <dependency>
+      <groupId>com.google.auto.value</groupId>
+      <artifactId>auto-value-annotations</artifactId>
+    </dependency>
     <dependency>
       <groupId>com.google.protobuf</groupId>
       <artifactId>protobuf-java-util</artifactId>
@@ -83,6 +87,10 @@
       <artifactId>objenesis</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>com.google.code.findbugs</groupId>
+      <artifactId>jsr305</artifactId>
+    </dependency>
     <dependency>
       <groupId>com.google.truth</groupId>
       <artifactId>truth</artifactId>

google-cloud-core/src/main/java/com/google/cloud/Binding.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright 2020 Google LLC
+ *
+ * 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.cloud;
+
+import com.google.api.core.BetaApi;
+import com.google.auto.value.AutoValue;
+import com.google.common.base.Predicate;
+import com.google.common.base.Predicates;
+import com.google.common.collect.Collections2;
+import com.google.common.collect.ImmutableList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import javax.annotation.Nullable;
+
+@BetaApi("This is a Beta API is not stable yet and may change in the future.")
+@AutoValue
+public abstract class Binding {
+  public abstract String getRole();
+
+  public abstract ImmutableList<String> getMembers();
+
+  @Nullable
+  public abstract Condition getCondition();
+
+  public abstract Builder toBuilder();
+
+  public static Builder newBuilder() {
+    return new AutoValue_Binding.Builder();
+  }
+
+  @AutoValue.Builder
+  public abstract static class Builder {
+    public abstract Builder setRole(String role);
+
+    public abstract Builder setMembers(List<String> members);
+
+    public abstract Builder setCondition(Condition condition);
+
+    public abstract String getRole();
+
+    public abstract ImmutableList<String> getMembers();
+
+    public abstract Condition getCondition();
+
+    // Members property must be initialized before this method can be used.
+    public Builder addMembers(String... members) {
+      ImmutableList.Builder<String> membersBuilder = ImmutableList.builder();
+      membersBuilder.addAll(getMembers());
+      for (String member : members) {
+        membersBuilder.add(member);
+      }
+      setMembers(membersBuilder.build());
+      return this;
+    }
+
+    // Members property must be initialized before this method can be used.
+    public Builder removeMembers(String... members) {
+      Predicate<String> selectMembersNotInList =
+          Predicates.not(Predicates.in(Arrays.asList(members)));
+      Collection<String> filter = Collections2.filter(getMembers(), selectMembersNotInList);
+      setMembers(ImmutableList.copyOf(filter));
+      return this;
+    }
+
+    public abstract Binding build();
+  }
+}

google-cloud-core/src/main/java/com/google/cloud/Condition.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2020 Google LLC
+ *
+ * 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.cloud;
+
+import com.google.api.core.BetaApi;
+import com.google.auto.value.AutoValue;
+import javax.annotation.Nullable;
+
+@BetaApi("This is a Beta API is not stable yet and may change in the future.")
+@AutoValue
+public abstract class Condition {
+  @Nullable
+  public abstract String getTitle();
+
+  @Nullable
+  public abstract String getDescription();
+
+  @Nullable
+  public abstract String getExpression();
+
+  public abstract Builder toBuilder();
+
+  public static Builder newBuilder() {
+    return new AutoValue_Condition.Builder();
+  }
+
+  @AutoValue.Builder
+  public abstract static class Builder {
+    public abstract Builder setTitle(String title);
+
+    public abstract Builder setDescription(String description);
+
+    public abstract Builder setExpression(String expression);
+
+    public abstract Condition build();
+  }
+}