The project state is managed by the `ProjectState` class.
It is created for each project in the build definition, once per build execution and is discarded at the end of the execution.

## Composition by architecture modules

Each [architecture module and platform](platforms.md) can contribute code to any of the elements.
Not every module contributes to every element.

Most source code targets the daemon and the remaining code either targets a single runtime, for example the Gradle client, or is shared across multiple runtimes.

## Composition by architecture modules

Each [architecture module and platform](platforms.md) can contribute code to any of the runtimes.
Not every module contributes to every runtime.

The core-runtime module defines each runtime:

            left.calculateExecutionTimeValue(visitor);
            right.calculateExecutionTimeValue(visitor);
        }
    }

    /**
     * A plus collector that either produces a composition of both of its left and right sides,
     * or Value.present() with empty content (if left or right side are missing).
     */
    private static class AbsentIgnoringPlusCollector<T> extends AbstractPlusCollector<T> {

            left.calculateExecutionTimeValue(visitor);
            right.calculateExecutionTimeValue(visitor);
        }
    }

    /**
     * A plus collector that either produces a composition of both of its left and right sides,
     * or Value.present() with empty content (if left or right side are missing).
     */
    private static class AbsentIgnoringPlusCollector<K, V> extends AbstractPlusCollector<K, V> {