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* Licensed under the Apache License, Version 2.0 (the "License");
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package org.jooq;
import java.util.Map;
import org.jooq.conf.Settings;
/**
* Scope implementations provide access to a variety of objects that are
* available from a given scope.
* <p>
* The scope of the various objects contained in this type (e.g.
* {@link #configuration()}, {@link #settings()}, etc.) are implementation
* dependent and will be specified by the concrete subtype of
* <code>Scope</code>. Examples of such scope types are:
* <ul>
* <li>{@link ExecuteContext}: A scope that covers a single execution of a
* {@link Query}</li>
* <li>{@link Context}: A scope that covers a single traversal of a
* {@link QueryPart} expression tree to produce a SQL string and / or a list of
* bind variables.</li>
* <li>{@link VisitContext}: A scope that that covers a single traversal of a
* {@link QueryPart} expression tree (just like {@link Context}), in the
* presence of at least one {@link VisitListener}.</li>
* <li>{@link RecordContext}: A scope that covers a single record operation,
* such as {@link UpdatableRecord#store()}.</li>
* <li>{@link TransactionContext}: A scope that covers the execution (or
* nesting) of a single transaction.</li>
* </ul>
* <p>
* One of <code>Scope</code>'s most interesting features for client code
* implementing any SPI is the {@link #data()} map, which provides access to a
* {@link Map} where client code can register user-defined values for the entire
* lifetime of a scope. For instance, in an {@link ExecuteListener}
* implementation that measures time for fetching data, it is perfectly possible
* to store timestamps in that map:
* <p>
* <code><pre>
* class FetchTimeMeasuringListener extends DefaultExecuteListener {
* @Override
* public void fetchStart(ExecuteContext ctx) {
*
* // Put any arbitrary object in this map:
* ctx.data("org.jooq.example.fetch-start-time", System.nanoTime());
* }
*
* @Override
* public void fetchEnd(ExecuteContext ctx) {
*
* // Retrieve that object again in a later step:
* Long startTime = (Long) ctx.data("org.jooq.example.fetch-start-time");
* System.out.println("Time taken: " + (System.nanoTime() - startTime) / 1000 / 1000.0 + " ms");
* }
* }
* </pre></code>
*
* @author Lukas Eder
*/
public interface Scope {
/**
* The configuration of the current scope.
*/
Configuration configuration();
/**
* The settings wrapped by this context.
* <p>
* This method is a convenient way of accessing
* <code>configuration().settings()</code>.
*/
Settings settings();
/**
* The {@link SQLDialect} wrapped by this context.
* <p>
* This method is a convenient way of accessing
* <code>configuration().dialect()</code>.
*/
SQLDialect dialect();
/**
* The {@link SQLDialect#family()} wrapped by this context.
* <p>
* This method is a convenient way of accessing
* <code>configuration().dialect().family()</code>.
*/
SQLDialect family();
/**
* Get all custom data from this <code>Scope</code>.
* <p>
* This is custom data that was previously set to the context using
* {@link #data(Object, Object)}. Use custom data if you want to pass data
* to {@link QueryPart} objects for a given {@link Scope}.
*
* @return The custom data. This is never <code>null</code>
*/
Map<Object, Object> data();
/**
* Get some custom data from this <code>Scope</code>.
* <p>
* This is custom data that was previously set to the context using
* {@link #data(Object, Object)}. Use custom data if you want to pass data
* to {@link QueryPart} objects for a given {@link Scope}
*
* @param key A key to identify the custom data
* @return The custom data or <code>null</code> if no such data is contained
* in this <code>Scope</code>
*/
Object data(Object key);
/**
* Set some custom data to this <code>Scope</code>.
* <p>
* This is custom data that was previously set to the context using
* {@link #data(Object, Object)}. Use custom data if you want to pass data
* to {@link QueryPart} objects for a given {@link Scope}.
*
* @param key A key to identify the custom data
* @param value The custom data
* @return The previously set custom data or <code>null</code> if no data
* was previously set for the given key
*/
Object data(Object key, Object value);
}