net.opentsdb.tree

Class Leaf

java.lang.Object

net.opentsdb.tree.Leaf

All Implemented Interfaces:

Comparable<Leaf>

public final class Leaf
extends Object
implements Comparable<Leaf>

A leaf in a tree. Each leaf is composed, primarily, of a display name and a TSUID. When stored, only the display name and TSUID are recorded. When accessed via an RPC call, the leaf should include the metric and tags.

Leaves are stored as individual columns in the same row as a branch. When a branch is loaded with leaves, each leaf is parsed and optionally the UID names are loaded from the TSD. Leaf columns are stored with the column qualifier: "leaf:<display_name.hashCode()>". When a leaf is written to storage, a CompareAndSet is executed with a null value expected for the compare. If the compare returns false, we load the leaf at that location and determine if it's the same leaf. If so, it's all good and we ignore the put. If the TSUID is different, we record a collision in the tree so that the user knows their rule set matched a timeseries that was already recorded.

Since:

2.0

Constructor Summary

Constructors

Constructor and Description
Leaf() Default empty constructor necessary for des/serialization
Leaf(String display_name, String tsuid) Optional constructor used when building a tree

Method Summary

Methods

Modifier and Type	Method and Description
byte[]	columnQualifier() Calculates the column qualifier for this leaf.
int	compareTo(Leaf leaf) Sorts on the display_name alphabetically
boolean	equals(Object obj) Just compares the TSUID of the two objects as we don't care about the rest
String	getDisplayName()
String	getMetric()
Map<String,String>	getTags()
String	getTsuid()
int	hashCode()
static byte[]	LEAF_PREFIX()
static com.stumbleupon.async.Deferred<Leaf>	parseFromStorage(TSDB tsdb, org.hbase.async.KeyValue column, boolean load_uids) Attempts to parse the leaf from the given column, optionally loading the UID names.
void	setDisplayName(String display_name)
void	setMetric(String metric)
void	setTags(HashMap<String,String> tags)
void	setTsuid(String tsuid)
com.stumbleupon.async.Deferred<Boolean>	storeLeaf(TSDB tsdb, byte[] branch_id, Tree tree) Attempts to write the leaf to storage using a CompareAndSet call.
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Leaf

public Leaf()

Default empty constructor necessary for des/serialization

Leaf

public Leaf(String display_name,
    String tsuid)

Optional constructor used when building a tree

Parameters:

display_name - The name of the leaf

tsuid - The TSUID of the leaf

Method Detail

hashCode

public int hashCode()

Overrides:

hashCode in class Object

Returns:

Hash code of the display name field

equals

public boolean equals(Object obj)

Just compares the TSUID of the two objects as we don't care about the rest

Overrides:

equals in class Object

Parameters:

obj - The object to compare this to

Returns:

True if the TSUIDs are the same or the incoming object has the same address

compareTo

public int compareTo(Leaf leaf)

Sorts on the display_name alphabetically

Specified by:

compareTo in interface Comparable<Leaf>

Parameters:

leaf - The leaf to compare against

Returns:

string comparison

toString

public String toString()

Overrides:

toString in class Object

Returns:

A string describing this object

columnQualifier

public byte[] columnQualifier()

Calculates the column qualifier for this leaf. The qualifier is of the format: "leaf:<display_name.hashCode()>"

Returns:

The qualifier as a byte array

Throws:

IllegalArgumentException - if the display_name hasn't been set yet

storeLeaf

public com.stumbleupon.async.Deferred<Boolean> storeLeaf(TSDB tsdb,
                                                byte[] branch_id,
                                                Tree tree)

Attempts to write the leaf to storage using a CompareAndSet call. We expect the stored value to be null. If it's not, we fetched the stored leaf. If the stored value is the TSUID as the local leaf, we return true since the caller is probably reprocessing a timeseries. If the stored TSUID is different, we store a collision in the tree and return false. Note: You MUST write the tree to storage after calling this as there may be a new collision. Check the tree's collision set.

Parameters:

tsdb - The TSDB to use for storage access

branch_id - ID of the branch this leaf belongs to

tree - Tree the leaf and branch belong to

Returns:

True if the leaf was stored successful or already existed, false if there was a collision

Throws:

org.hbase.async.HBaseException - if there was an issue

JSONException - if the object could not be serialized

parseFromStorage

public static com.stumbleupon.async.Deferred<Leaf> parseFromStorage(TSDB tsdb,
                                                    org.hbase.async.KeyValue column,
                                                    boolean load_uids)

Attempts to parse the leaf from the given column, optionally loading the UID names. This is used by the branch loader when scanning an entire row. Note: The column better have a qualifier that starts with "leaf:" or we're likely to throw a parsing exception.

Parameters:

tsdb - The TSDB to use for storage access

column - Column to parse a leaf from

load_uids - Whether or not to load UID names from the TSD

Returns:

The parsed leaf if successful

Throws:

IllegalArgumentException - if the column was missing data

NoSuchUniqueId - If any of the UID name mappings do not exist

org.hbase.async.HBaseException - if there was an issue

JSONException - if the object could not be serialized

LEAF_PREFIX

public static byte[] LEAF_PREFIX()

Returns:

The configured leaf column prefix

getMetric

public String getMetric()

Returns:

The metric associated with this TSUID

getTags

public Map<String,String> getTags()

Returns:

The tags associated with this TSUID

getDisplayName

public String getDisplayName()

Returns:

The public name of this leaf

getTsuid

public String getTsuid()

Returns:

the tsuid

setMetric

public void setMetric(String metric)

Parameters:

metric - The metric associated with this TSUID

setTags

public void setTags(HashMap<String,String> tags)

Parameters:

tags - The tags associated with this TSUID

setDisplayName

public void setDisplayName(String display_name)

Parameters:

display_name - Public display name for the leaf

setTsuid

public void setTsuid(String tsuid)

Parameters:

tsuid - the tsuid to set