Package org.intellij.lang.annotations

## Annotation Type Flow

-     @Retention(CLASS)
      @Target({PARAMETER,METHOD})
      public @interface Flow

  This annotation assists the 'Data flow to this' feature by describing data flow from the method parameter to the corresponding container (e.g. `ArrayList.add(item)`) or from the container to the method return value (e.g. `Set.toArray()`) or between method parameters (e.g. `System.arraycopy(array1, 0, array2, length)`)

- - ### Field Summary

    Fields
    Modifier and Type | Fields | Description
    --- | --- | ---
    `static String` | `DEFAULT_SOURCE` |
    `static String` | `DEFAULT_TARGET` |
    `static String` | `RETURN_METHOD_TARGET` |
    `static String` | `THIS_SOURCE` |
    `static String` | `THIS_TARGET` |

  - ### Optional Element Summary

    Optional Elements
    Modifier and Type | Optional Element | Description
    --- | --- | ---
    `String` | `source` | Denotes the source of the data flow. Allowed values are: `THIS_SOURCE` - Means that the data flows from this container. E.g.
    `boolean` | `sourceIsContainer` | true if the data source is container and we should track not the expression but its contents. E.g.
    `String` | `target` | Denotes the destination of the data flow. Allowed values are: `THIS_TARGET` - Means that the data flows inside this container (of the class the annotated method belongs to). E.g.
    `boolean` | `targetIsContainer` | true if the data target is container and we should track not the expression but its contents. E.g.

- - ### Field Detail

    - #### DEFAULT_SOURCE

          static final String DEFAULT_SOURCE

  - - #### THIS_SOURCE

          static final String THIS_SOURCE

  - - #### DEFAULT_TARGET

          static final String DEFAULT_TARGET

  - - #### RETURN_METHOD_TARGET

          static final String RETURN_METHOD_TARGET

  - - #### THIS_TARGET

          static final String THIS_TARGET

  - ### Element Detail

    - #### source

          String source

      Denotes the source of the data flow.
      Allowed values are:
      - `THIS_SOURCE` - Means that the data flows from this container.
        E.g. annotation for java.util.List method get(index) means the method reads contents of list and returns it.
        `@Flow(source = THIS_SOURCE) T get(int index);`
      - `this.`Field name - means that the data flows from this container some (synthetic) field.
        E.g. annotation for java.util.Map.keySet() method here means that it returns data from the map from the field named "keys".
        `@Flow(source = "this.keys") Set<K> keySet();`
      By default, the source() value is:
      - `THIS_SOURCE` if the method was annotated, e.g.
        `@Flow(sourceIsContainer=true, targetIsContainer=true) Object[] Collection.toArray()`
        Here the annotation tells us that java.util.Collection.toArray() method
        reads the contents of this collection (source=THIS_SOURCE by default) and passes it outside.
      - Corresponding argument if the method parameter was annotated, e.g.
        `void List.add(@Flow(targetIsContainer=true) E item)`
        Here the annotation tells us that java.util.List.add(E item) method
        takes the argument (source="item" by default) and passes it to this collection.
      Default:
        "The method argument (if parameter was annotated) or this container (if instance method was annotated)"

  - - #### sourceIsContainer

          boolean sourceIsContainer

      true if the data source is container and we should track not the expression but its contents.
      E.g. the java.util.ArrayList constructor takes the collection and stores its contents:
      ArrayList(

          @Flow(sourceIsContainer=true, targetIsContainer=true) Collection<? extends E> collection

      )
      By default it's false.
      Default:
        false

  - - #### target

          String target

      Denotes the destination of the data flow.
      Allowed values are:
      - `THIS_TARGET` - Means that the data flows inside this container (of the class the annotated method belongs to).
        E.g. annotation for java.util.List method add(element) means the method takes the argument and passes it to this collection.
        `boolean add(@Flow(target=THIS_TARGET, targetIsContainer=true) E element);`
      - Parameter name - means the data flows to this parameter.
        E.g.
        `void arraycopy(@Flow(sourceIsContainer=true, target="dest", targetIsContainer=true) Object src, int srcPos, Object dest, int destPos, int length)`
        means that java.lang.System.arraycopy() method takes its first argument and passes it to the "dest" parameter.
      - `this.`Field name - means that the data flows to this container in some (synthetic) field.
        E.g. annotation for java.util.Map.put(key, value) method here means that it takes the argument 'key' and stores the data in some (hidden) field named "keys".
        `V put(@Flow(target = "this.keys", targetIsContainer=true) K key, V value);`
      By default, the target() value is:
      - `THIS_TARGET` if the parameter was annotated, e.g.
        `void List.set(int index, @Flow(targetIsContainer=true) E element)`
        Here the annotation tells us that java.util.List.set(index, element) method
        reads its second argument 'element' and passes it to this collection (target=THIS_TARGET by default).
      - `RETURN_METHOD_TARGET` if the method was annotated, e.g.:
        `@Flow(sourceIsContainer=true) E List.remove(int index)`
        Here the annotation tells us that java.util.List.remove(int index) method
        returns the data from its collection (target=RETURN_METHOD_TARGET by default).
      Default:
        "This container (if the parameter was annotated) or the return value (if instance method was annotated)"

  - - #### targetIsContainer

          boolean targetIsContainer

      true if the data target is container and we should track not the expression but its contents.
      E.g. the java.lang.System.arraycopy() method parameter 'dest' is actually an array:
      `void arraycopy(@Flow(sourceIsContainer=true, target="dest", targetIsContainer=true) Object src, int srcPos, Object dest, int destPos, int length)`
      By default it's false.
      Default:
        false