Memory (Apache TinkerPop 3.1.1-incubating API)

All Known Subinterfaces:

Memory.Admin

All Known Implementing Classes:

GiraphMemory, ImmutableMemory, MapMemory, SparkMemory, TinkerMemory
```
public interface Memory
```
The Memory of a GraphComputer is a global data structure where by vertices can communicate information with one another. Moreover, it also contains global information about the state of the computation such as runtime and the current iteration. The Memory data is logically updated in parallel using associative/commutative methods which have embarrassingly parallel implementations.

Author:

Marko A. Rodriguez (http://markorodriguez.com)

Nested Class Summary

Nested Classes
Modifier and Type	Interface and Description
`static interface`	`Memory.Admin` The Admin interface is used by the `GraphComputer` to update the Memory.
`static class`	`Memory.Exceptions`

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method and Description
`void`	`and(String key, boolean bool)` Logically AND the provided boolean value with the boolean value currently stored at the key.
`default Map<String,Object>`	`asMap()` A helper method that generates a `Map` of the memory key/values.
`default boolean`	`exists(String key)` Whether the key exists in the memory.
`<R> R`	`get(String key)` Get the value associated with the provided key.
`int`	`getIteration()` Get the current iteration number.
`long`	`getRuntime()` Get the amount of milliseconds the `GraphComputer` has been executing thus far.
`void`	`incr(String key, long delta)` Add the provided delta value to the long value currently stored at the key.
`default boolean`	`isInitialIteration()` A helper method that states whether the current iteration is 0.
`Set<String>`	`keys()` The set of keys currently associated with this memory.
`void`	`or(String key, boolean bool)` Logically OR the provided boolean value with the boolean value currently stored at the key.
`void`	`set(String key, Object value)` Set the value of the provided key.

- Method Detail
  - exists
```
default boolean exists(String key)
```
    Whether the key exists in the memory.
    
    Parameters:
    
    key - key to search the memory for.
    
    Returns:
    
    whether the key exists
  - keys
```
Set<String> keys()
```
    The set of keys currently associated with this memory.
    
    Returns:
    
    the memory's key set.
  - get
```
<R> R get(String key)
   throws IllegalArgumentException
```
    Get the value associated with the provided key.
    
    Type Parameters:
    
    R - the type of the value
    
    Parameters:
    
    key - the key of the value
    
    Returns:
    
    the value
    
    Throws:
    
    IllegalArgumentException - is thrown if the key does not exist
  - set
```
void set(String key,
         Object value)
```
    Set the value of the provided key. This is typically called in setup() and/or terminate() of the VertexProgram. If this is called during execute(), there is no guarantee as to the ultimately stored value as call order is indeterminate.
    
    Parameters:
    
    key - they key to set a value for
    
    value - the value to set for the key
  - asMap
```
default Map<String,Object> asMap()
```
    A helper method that generates a Map of the memory key/values.
    
    Returns:
    
    the map representation of the memory key/values
  - getIteration
```
int getIteration()
```
    Get the current iteration number.
    
    Returns:
    
    the current iteration
  - getRuntime
```
long getRuntime()
```
    Get the amount of milliseconds the GraphComputer has been executing thus far.
    
    Returns:
    
    the total time in milliseconds
  - incr
```
void incr(String key,
          long delta)
```
    Add the provided delta value to the long value currently stored at the key.
    
    Parameters:
    
    key - the key of the long value
    
    delta - the adjusting amount (can be negative for decrement)
  - and
```
void and(String key,
         boolean bool)
```
    Logically AND the provided boolean value with the boolean value currently stored at the key.
    
    Parameters:
    
    key - the key of the boolean value
    
    bool - the boolean to AND
  - or
```
void or(String key,
        boolean bool)
```
    Logically OR the provided boolean value with the boolean value currently stored at the key.
    
    Parameters:
    
    key - the key of the boolean value
    
    bool - the boolean to OR
  - isInitialIteration
```
default boolean isInitialIteration()
```
    A helper method that states whether the current iteration is 0.
    
    Returns:
    
    whether this is the first iteration

Interface Memory

Nested Class Summary

Method Summary

Method Detail

exists

keys

get

set

asMap

getIteration

getRuntime

incr

and

or

isInitialIteration