org.jtrim2.taskgraph.TaskGraphBuilderProperties Maven / Gradle / Ivy
package org.jtrim2.taskgraph;
import java.util.Objects;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* Defines the properties used to control task graph building (not its execution).
*
* Instances of this class can can be instantiated through its
* {@link TaskGraphBuilderProperties.Builder TaskGraphBuilderProperties.Builder}.
*
* This class maybe extended by more specific implementations of the task execution framework.
*
*
Thread safety
* Methods of this class are safely callable from multiple threads concurrently and
* the properties of {@code TaskGraphBuilderProperties} cannot be changed.
*
* Synchronization transparency
* The methods of this class are synchronization transparent.
*
* @see TaskGraphBuilder
*/
public class TaskGraphBuilderProperties {
private static final Logger LOGGER = Logger.getLogger(TaskGraphBuilderProperties.class.getName());
private final TaskFactoryProperties defaultFactoryProperties;
private final TaskErrorHandler nodeCreateErrorHandler;
/**
* Sets the properties of the {@code TaskGraphBuilderProperties} from the current
* value of the passed {@code Builder}.
*
* @param builder the builder from which a snapshot is created from. This argument
* cannot be {@code null}.
*/
protected TaskGraphBuilderProperties(Builder builder) {
this.defaultFactoryProperties = builder.defaultFactoryProperties.build();
this.nodeCreateErrorHandler = builder.nodeCreateErrorHandler;
}
/**
* Returns the default values of the properties used by the task node factories. The task node
* factories themselves may override any value but every task node factory will use these
* values by default.
*
* Subclasses may override this method to further specify the return type.
*
* @return the default values of the properties used by the task nodes. This method
* never returns {@code null}.
*/
public TaskFactoryProperties getDefaultFactoryProperties() {
return defaultFactoryProperties;
}
/**
* Returns the callback notified whenever a failure occurs while trying to create a node
* with the associated task factory. The default callback simply logs the error on SEVERE
* level.
*
* @return the callback notified whenever a failure occurs while trying to create a node
* with the associated task factory. This method never returns {@code null}.
*/
public final TaskErrorHandler getNodeCreateErrorHandler() {
return nodeCreateErrorHandler;
}
private static void logNodeCreateError(TaskNodeKey nodeKey, Throwable error) {
LOGGER.log(Level.SEVERE, "Failure while creating node with key: " + nodeKey, error);
}
/**
* The {@code Builder} used to create {@link TaskGraphBuilderProperties} instances.
*
*
Thread safety
* The methods of this class may not be used from multiple threads concurrently.
*
* Synchronization transparency
* The methods of this class are synchronization transparent.
*/
public static class Builder {
private final TaskFactoryProperties.Builder defaultFactoryProperties;
private TaskErrorHandler nodeCreateErrorHandler;
/**
* Initializes the {@code Builder} with the default values:
*
* -
* nodeCreateErrorHandler: A callback logging the error on SEVERE level.
*
*
*/
public Builder() {
this.defaultFactoryProperties = new TaskFactoryProperties.Builder();
this.nodeCreateErrorHandler = TaskGraphBuilderProperties::logNodeCreateError;
}
/**
* Initializes the {@code Builder} with the values of the given {@code TaskGraphBuilderProperties}.
* Immediately creating a {@code TaskGraphBuilderProperties} from this {@code Builder} will yield
* an effectively equivalent {@code TaskGraphBuilderProperties} as the argument.
*
* @param defaults the default values used to initialize the {@code Builder}.
* This argument cannot be {@code null}.
*/
public Builder(TaskGraphBuilderProperties defaults) {
this.defaultFactoryProperties = new TaskFactoryProperties.Builder(defaults.getDefaultFactoryProperties());
this.nodeCreateErrorHandler = defaults.nodeCreateErrorHandler;
}
/**
* Returns the default values of the properties used by the task node factories. These values
* might be adjusted by the caller. However, they must be adjusted before calling {@link #build() build()}.
*
* Subclasses may override this method to further specify the return type.
*
* @return the default values of the properties used by the task nodes. This method never returns
* {@code null}.
*/
public TaskFactoryProperties.Builder defaultFactoryProperties() {
return defaultFactoryProperties;
}
/**
* Sets the callback notified whenever a failure occurs while trying to create a node
* with the associated task factory. Setting the callback will override any previously set value.
*
* @param nodeCreateErrorHandler the callback notified whenever a failure occurs while trying
* to create a node with the associated task factory. This argument cannot be {@code null}.
*/
public final void setNodeCreateErrorHandler(TaskErrorHandler nodeCreateErrorHandler) {
Objects.requireNonNull(nodeCreateErrorHandler, "nodeCreateErrorHandler");
this.nodeCreateErrorHandler = nodeCreateErrorHandler;
}
/**
* Creates a snapshot of the current state of this {@code Builder}. Further adjustment of
* this {@code Builder} will not affect the returned {@code TaskGraphBuilderProperties}.
*
* @return a snapshot of the current state of this {@code Builder}. This method may never
* return {@code null}.
*/
public TaskGraphBuilderProperties build() {
return new TaskGraphBuilderProperties(this);
}
}
}