YARN-1659. Defined the ApplicationTimelineStore store as an abstraction for implementing different storage impls for storing timeline information. Contributed by Billie Rinaldi.

svn merge --ignore-ancestry -c 1564037 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1564038 13f79535-47bb-0310-9956-ffa450edef68

hadoop-yarn-project/CHANGES.txt

@@ -63,6 +63,10 @@ Release 2.4.0 - UNRELEASED
     used by ResourceManager to read configuration locally or from remote systems
     so as to help RM failover. (Xuan Gong via vinodkv)
 
+    YARN-1659. Defined the ApplicationTimelineStore store as an abstraction for
+    implementing different storage impls for storing timeline information.
+    (Billie Rinaldi via vinodkv)
+
   IMPROVEMENTS
 
     YARN-1007. Enhance History Reader interface for Containers. (Mayank Bansal via

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/api/records/apptimeline/ATSEntity.java

@@ -22,6 +22,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Map.Entry;
 
 import javax.xml.bind.annotation.XmlAccessType;
 import javax.xml.bind.annotation.XmlAccessorType;
@@ -53,10 +54,10 @@ public class ATSEntity {
 
   private String entityType;
   private String entityId;
-  private long startTime;
+  private Long startTime;
   private List<ATSEvent> events = new ArrayList<ATSEvent>();
-  private Map<String, List<Object>> relatedEntities =
+  private Map<String, List<String>> relatedEntities =
-      new HashMap<String, List<Object>>();
+      new HashMap<String, List<String>>();
   private Map<String, Object> primaryFilters =
       new HashMap<String, Object>();
   private Map<String, Object> otherInfo =
@@ -112,7 +113,7 @@ public class ATSEntity {
    * @return the start time of the entity
    */
   @XmlElement(name = "starttime")
-  public long getStartTime() {
+  public Long getStartTime() {
     return startTime;
   }
 
@@ -122,7 +123,7 @@ public class ATSEntity {
    * @param startTime
    *          the start time of the entity
    */
-  public void setStartTime(long startTime) {
+  public void setStartTime(Long startTime) {
     this.startTime = startTime;
   }
 
@@ -172,26 +173,25 @@ public class ATSEntity {
    * @return the related entities
    */
   @XmlElement(name = "relatedentities")
-  public Map<String, List<Object>> getRelatedEntities() {
+  public Map<String, List<String>> getRelatedEntities() {
     return relatedEntities;
   }
 
   /**
-   * Add a list of entity of the same type to the existing related entity map
+   * Add an entity to the existing related entity map
    * 
    * @param entityType
    *          the entity type
-   * @param entityIds
+   * @param entityId
-   *          a list of entity Ids
+   *          the entity Id
    */
-  public void addRelatedEntity(String entityType, List<Object> entityIds) {
+  public void addRelatedEntity(String entityType, String entityId) {
-    List<Object> thisRelatedEntity = relatedEntities.get(entityType);
+    List<String> thisRelatedEntity = relatedEntities.get(entityType);
-    relatedEntities.put(entityType, entityIds);
     if (thisRelatedEntity == null) {
-      relatedEntities.put(entityType, entityIds);
+      thisRelatedEntity = new ArrayList<String>();
-    } else {
+      relatedEntities.put(entityType, thisRelatedEntity);
-      thisRelatedEntity.addAll(entityIds);
     }
+    thisRelatedEntity.add(entityId);
   }
 
   /**
@@ -200,11 +200,10 @@ public class ATSEntity {
    * @param relatedEntities
    *          a map of related entities
    */
-  public void addRelatedEntities(
+  public void addRelatedEntities(Map<String, List<String>> relatedEntities) {
-      Map<String, List<Object>> relatedEntities) {
+    for (Entry<String, List<String>> relatedEntity :
-    for (Map.Entry<String, List<Object>> relatedEntity : relatedEntities
+        relatedEntities.entrySet()) {
-        .entrySet()) {
+      List<String> thisRelatedEntity =
-      List<Object> thisRelatedEntity =
           this.relatedEntities.get(relatedEntity.getKey());
       if (thisRelatedEntity == null) {
         this.relatedEntities.put(
@@ -222,7 +221,7 @@ public class ATSEntity {
    *          a map of related entities
    */
   public void setRelatedEntities(
-      Map<String, List<Object>> relatedEntities) {
+      Map<String, List<String>> relatedEntities) {
     this.relatedEntities = relatedEntities;
   }
 

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/api/records/apptimeline/ATSEvent.java

@@ -39,7 +39,7 @@ import org.apache.hadoop.classification.InterfaceStability.Unstable;
 @XmlAccessorType(XmlAccessType.NONE)
 @Public
 @Unstable
-public class ATSEvent {
+public class ATSEvent implements Comparable<ATSEvent> {
 
   private long timestamp;
   private String eventType;
@@ -131,4 +131,42 @@ public class ATSEvent {
     this.eventInfo = eventInfo;
   }
 
+  @Override
+  public int compareTo(ATSEvent other) {
+    if (timestamp > other.timestamp) {
+      return -1;
+    } else if (timestamp < other.timestamp) {
+      return 1;
+    } else {
+      return eventType.compareTo(other.eventType);
+    }
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o)
+      return true;
+    if (o == null || getClass() != o.getClass())
+      return false;
+
+    ATSEvent atsEvent = (ATSEvent) o;
+
+    if (timestamp != atsEvent.timestamp)
+      return false;
+    if (!eventType.equals(atsEvent.eventType))
+      return false;
+    if (eventInfo != null ? !eventInfo.equals(atsEvent.eventInfo) :
+        atsEvent.eventInfo != null)
+      return false;
+
+    return true;
+  }
+
+  @Override
+  public int hashCode() {
+    int result = (int) (timestamp ^ (timestamp >>> 32));
+    result = 31 * result + eventType.hashCode();
+    result = 31 * result + (eventInfo != null ? eventInfo.hashCode() : 0);
+    return result;
+  }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/api/records/apptimeline/ATSEvents.java

@@ -160,7 +160,7 @@ public class ATSEvents {
      * @param event
      *          a single event
      */
-    public void addEntity(ATSEvent event) {
+    public void addEvent(ATSEvent event) {
       events.add(event);
     }
 

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/api/records/apptimeline/ATSPutErrors.java

@@ -0,0 +1,163 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.hadoop.yarn.api.records.apptimeline;
+
+import org.apache.hadoop.classification.InterfaceAudience.Public;
+import org.apache.hadoop.classification.InterfaceStability.Unstable;
+
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+import javax.xml.bind.annotation.XmlElement;
+import javax.xml.bind.annotation.XmlRootElement;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A class that holds a list of put errors.  This is the response returned
+ * when a list of {@link ATSEntity} objects is added to the application
+ * timeline.  If there are errors in storing individual entity objects,
+ * they will be indicated in the list of errors.
+ */
+@XmlRootElement(name = "errors")
+@XmlAccessorType(XmlAccessType.NONE)
+@Public
+@Unstable
+public class ATSPutErrors {
+
+  private List<ATSPutError> errors = new ArrayList<ATSPutError>();
+
+  public ATSPutErrors() {
+
+  }
+
+  /**
+   * Get a list of {@link ATSPutError} instances
+   *
+   * @return a list of {@link ATSPutError} instances
+   */
+  @XmlElement(name = "errors")
+  public List<ATSPutError> getErrors() {
+    return errors;
+  }
+
+  /**
+   * Add a single {@link ATSPutError} instance into the existing list
+   *
+   * @param error
+   *          a single {@link ATSPutError} instance
+   */
+  public void addError(ATSPutError error) {
+    errors.add(error);
+  }
+
+  /**
+   * Add a list of {@link ATSPutError} instances into the existing list
+   *
+   * @param errors
+   *          a list of {@link ATSPutError} instances
+   */
+  public void addErrors(List<ATSPutError> errors) {
+    this.errors.addAll(errors);
+  }
+
+  /**
+   * Set the list to the given list of {@link ATSPutError} instances
+   *
+   * @param errors
+   *          a list of {@link ATSPutError} instances
+   */
+  public void setErrors(List<ATSPutError> errors) {
+    this.errors.clear();
+    this.errors.addAll(errors);
+  }
+
+  /**
+   * A class that holds the error code for one entity.
+   */
+  @XmlRootElement(name = "error")
+  @XmlAccessorType(XmlAccessType.NONE)
+  @Public
+  @Unstable
+  public static class ATSPutError {
+    private String entityId;
+    private String entityType;
+    private Integer errorCode;
+
+    /**
+     * Get the entity Id
+     *
+     * @return the entity Id
+     */
+    @XmlElement(name = "entity")
+    public String getEntityId() {
+      return entityId;
+    }
+
+    /**
+     * Set the entity Id
+     *
+     * @param entityId
+     *          the entity Id
+     */
+    public void setEntityId(String entityId) {
+      this.entityId = entityId;
+    }
+
+    /**
+     * Get the entity type
+     *
+     * @return the entity type
+     */
+    @XmlElement(name = "entitytype")
+    public String getEntityType() {
+      return entityType;
+    }
+
+    /**
+     * Set the entity type
+     *
+     * @param entityType
+     *          the entity type
+     */
+    public void setEntityType(String entityType) {
+      this.entityType = entityType;
+    }
+
+    /**
+     * Get the error code
+     *
+     * @return an error code
+     */
+    @XmlElement(name = "errorcode")
+    public Integer getErrorCode() {
+      return errorCode;
+    }
+
+    /**
+     * Set the error code to the given error code
+     *
+     * @param errorCode
+     *          an error code
+     */
+    public void setErrorCode(Integer errorCode) {
+      this.errorCode = errorCode;
+    }
+
+  }
+
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/api/records/apptimeline/TestApplicationTimelineRecords.java

@@ -18,10 +18,13 @@
 
 package org.apache.hadoop.yarn.api.records.apptimeline;
 
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 
 import junit.framework.Assert;
 
+import org.apache.hadoop.yarn.api.records.apptimeline.ATSPutErrors.ATSPutError;
 import org.junit.Test;
 
 public class TestApplicationTimelineRecords {
@@ -42,10 +45,8 @@ public class TestApplicationTimelineRecords {
         event.addEventInfo("key2", "val2");
         entity.addEvent(event);
       }
-      entity.addRelatedEntity(
+      entity.addRelatedEntity("test ref type 1", "test ref id 1");
-          "test ref type 1", Arrays.asList((Object) "test ref id 1"));
+      entity.addRelatedEntity("test ref type 2", "test ref id 2");
-      entity.addRelatedEntity(
-          "test ref type 2", Arrays.asList((Object) "test ref id 2"));
       entity.addPrimaryFilter("pkey1", "pval1");
       entity.addPrimaryFilter("pkey2", "pval2");
       entity.addOtherInfo("okey1", "oval1");
@@ -83,7 +84,7 @@ public class TestApplicationTimelineRecords {
         event.setEventType("event type " + i);
         event.addEventInfo("key1", "val1");
         event.addEventInfo("key2", "val2");
-        partEvents.addEntity(event);
+        partEvents.addEvent(event);
       }
       events.addEvent(partEvents);
     }
@@ -110,4 +111,36 @@ public class TestApplicationTimelineRecords {
     Assert.assertEquals(2, event22.getEventInfo().size());
   }
 
+  @Test
+  public void testATSPutErrors() {
+    ATSPutErrors atsPutErrors = new ATSPutErrors();
+    ATSPutError error1 = new ATSPutError();
+    error1.setEntityId("entity id 1");
+    error1.setEntityId("entity type 1");
+    error1.setErrorCode(1);
+    atsPutErrors.addError(error1);
+    List<ATSPutError> errors = new ArrayList<ATSPutError>();
+    errors.add(error1);
+    ATSPutError error2 = new ATSPutError();
+    error2.setEntityId("entity id 2");
+    error2.setEntityId("entity type 2");
+    error2.setErrorCode(2);
+    errors.add(error2);
+    atsPutErrors.addErrors(errors);
+
+    Assert.assertEquals(3, atsPutErrors.getErrors().size());
+    ATSPutError e = atsPutErrors.getErrors().get(0);
+    Assert.assertEquals(error1.getEntityId(), e.getEntityId());
+    Assert.assertEquals(error1.getEntityType(), e.getEntityType());
+    Assert.assertEquals(error1.getErrorCode(), e.getErrorCode());
+    e = atsPutErrors.getErrors().get(1);
+    Assert.assertEquals(error1.getEntityId(), e.getEntityId());
+    Assert.assertEquals(error1.getEntityType(), e.getEntityType());
+    Assert.assertEquals(error1.getErrorCode(), e.getErrorCode());
+    e = atsPutErrors.getErrors().get(2);
+    Assert.assertEquals(error2.getEntityId(), e.getEntityId());
+    Assert.assertEquals(error2.getEntityType(), e.getEntityType());
+    Assert.assertEquals(error2.getErrorCode(), e.getErrorCode());
+  }
+
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-applicationhistoryservice/src/main/java/org/apache/hadoop/yarn/server/applicationhistoryservice/apptimeline/ApplicationTimelineReader.java

@@ -0,0 +1,125 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.hadoop.yarn.server.applicationhistoryservice.apptimeline;
+
+import java.util.Collection;
+import java.util.EnumSet;
+import java.util.Set;
+import java.util.SortedSet;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.yarn.api.records.apptimeline.ATSEntities;
+import org.apache.hadoop.yarn.api.records.apptimeline.ATSEntity;
+import org.apache.hadoop.yarn.api.records.apptimeline.ATSEvents;
+
+/**
+ * This interface is for retrieving application timeline information.
+ */
+@InterfaceAudience.Private
+@InterfaceStability.Unstable
+public interface ApplicationTimelineReader {
+
+  /**
+   * Possible fields to retrieve for {@link #getEntities} and {@link
+   * #getEntity}.
+   */
+  enum Field {
+    EVENTS,
+    RELATED_ENTITIES,
+    PRIMARY_FILTERS,
+    OTHER_INFO,
+    LAST_EVENT_ONLY
+  }
+
+  /**
+   * Default limit for {@link #getEntities} and {@link #getEntityTimelines}.
+   */
+  final long DEFAULT_LIMIT = 100;
+
+  /**
+   * This method retrieves a list of entity information, {@link ATSEntity},
+   * sorted by the starting timestamp for the entity, descending.
+   *
+   * @param entityType The type of entities to return (required).
+   * @param limit A limit on the number of entities to return. If null,
+   *              defaults to {@link #DEFAULT_LIMIT}.
+   * @param windowStart The earliest start timestamp to retrieve (exclusive).
+   *                    If null, defaults to retrieving all entities until the
+   *                    limit is reached.
+   * @param windowEnd The latest start timestamp to retrieve (inclusive).
+   *                  If null, defaults to {@link Long#MAX_VALUE}
+   * @param primaryFilter Retrieves only entities that have the specified
+   *                      primary filter. If null, retrieves all entities.
+   *                      This is an indexed retrieval, and no entities that
+   *                      do not match the filter are scanned.
+   * @param secondaryFilters Retrieves only entities that have exact matches
+   *                         for all the specified filters in their primary
+   *                         filters or other info. This is not an indexed
+   *                         retrieval, so all entities are scanned but only
+   *                         those matching the filters are returned.
+   * @param fieldsToRetrieve Specifies which fields of the entity object to
+   *                         retrieve (see {@link Field}). If the set of fields
+   *                         contains {@link Field#LAST_EVENT_ONLY} and not
+   *                         {@link Field#EVENTS}, the most recent event for
+   *                         each entity is retrieved.
+   * @return An {@link ATSEntities} object.
+   */
+  ATSEntities getEntities(String entityType,
+      Long limit, Long windowStart, Long windowEnd,
+      NameValuePair primaryFilter, Collection<NameValuePair> secondaryFilters,
+      EnumSet<Field> fieldsToRetrieve);
+
+  /**
+   * This method retrieves the entity information for a given entity.
+   *
+   * @param entity The entity whose information will be retrieved.
+   * @param entityType The type of the entity.
+   * @param fieldsToRetrieve Specifies which fields of the entity object to
+   *                         retrieve (see {@link Field}). If the set of
+   *                         fields contains {@link Field#LAST_EVENT_ONLY} and
+   *                         not {@link Field#EVENTS}, the most recent event
+   *                         for each entity is retrieved.
+   * @return An {@link ATSEntity} object.
+   */
+  ATSEntity getEntity(String entity, String entityType, EnumSet<Field>
+      fieldsToRetrieve);
+
+  /**
+   * This method retrieves the events for a list of entities all of the same
+   * entity type. The events for each entity are sorted in order of their
+   * timestamps, descending.
+   *
+   * @param entityType The type of entities to retrieve events for.
+   * @param entityIds The entity IDs to retrieve events for.
+   * @param limit A limit on the number of events to return for each entity.
+   *              If null, defaults to  {@link #DEFAULT_LIMIT} events per
+   *              entity.
+   * @param windowStart If not null, retrieves only events later than the
+   *                    given time (exclusive)
+   * @param windowEnd If not null, retrieves only events earlier than the
+   *                  given time (inclusive)
+   * @param eventTypes Restricts the events returned to the given types. If
+   *                   null, events of all types will be returned.
+   * @return An {@link ATSEvents} object.
+   */
+  ATSEvents getEntityTimelines(String entityType,
+      SortedSet<String> entityIds, Long limit, Long windowStart,
+      Long windowEnd, Set<String> eventTypes);
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-applicationhistoryservice/src/main/java/org/apache/hadoop/yarn/server/applicationhistoryservice/apptimeline/ApplicationTimelineStore.java

@@ -0,0 +1,29 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.hadoop.yarn.server.applicationhistoryservice.apptimeline;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.service.Service;
+
+@InterfaceAudience.Private
+@InterfaceStability.Unstable
+public interface ApplicationTimelineStore extends
+    Service, ApplicationTimelineReader, ApplicationTimelineWriter {
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-applicationhistoryservice/src/main/java/org/apache/hadoop/yarn/server/applicationhistoryservice/apptimeline/ApplicationTimelineWriter.java

@@ -0,0 +1,43 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.hadoop.yarn.server.applicationhistoryservice.apptimeline;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.yarn.api.records.apptimeline.ATSEntities;
+import org.apache.hadoop.yarn.api.records.apptimeline.ATSPutErrors;
+
+/**
+ * This interface is for storing application timeline information.
+ */
+@InterfaceAudience.Private
+@InterfaceStability.Unstable
+public interface ApplicationTimelineWriter {
+
+  /**
+   * Stores entity information to the application timeline store. Any errors
+   * occurring for individual put request objects will be reported in the
+   * response.
+   *
+   * @param data An {@link ATSEntities} object.
+   * @return An {@link ATSPutErrors} object.
+   */
+  ATSPutErrors put(ATSEntities data);
+
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-applicationhistoryservice/src/main/java/org/apache/hadoop/yarn/server/applicationhistoryservice/apptimeline/NameValuePair.java

@@ -0,0 +1,59 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.hadoop.yarn.server.applicationhistoryservice.apptimeline;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+
+/**
+ * A class holding a name and value pair, used for specifying filters in
+ * {@link ApplicationTimelineReader}.
+ */
+@InterfaceAudience.Private
+@InterfaceStability.Unstable
+public class NameValuePair {
+  String name;
+  Object value;
+
+  public NameValuePair(String name, Object value) {
+    this.name = name;
+    this.value = value;
+  }
+
+  /**
+   * Get the name.
+   * @return The name.
+   */
+  public String getName() {
+
+    return name;
+  }
+
+  /**
+   * Get the value.
+   * @return The value.
+   */
+  public Object getValue() {
+    return value;
+  }
+
+  @Override
+  public String toString() {
+    return "{ name: " + name + ", value: " + value + " }";
+  }
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-applicationhistoryservice/src/main/java/org/apache/hadoop/yarn/server/applicationhistoryservice/apptimeline/package-info.java

@@ -0,0 +1,20 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+@InterfaceAudience.Private
+package org.apache.hadoop.yarn.server.applicationhistoryservice.apptimeline;
+import org.apache.hadoop.classification.InterfaceAudience;