org.apache.sling.scripting.sightly.compiler.commands.CommandStream Maven / Gradle / Ivy

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package org.apache.sling.scripting.sightly.compiler.commands;

import java.util.List;

import org.osgi.annotation.versioning.ProviderType;

/**
 * 

 *     This interface defines a stream to which {@link Command}s are pushed during the compilation of a HTL script by the {@link
 *     org.apache.sling.scripting.sightly.compiler.SightlyCompiler}. Depending on how a consumer wants to use the stream there are several
 *     options:
 * 
 * 
 *     if the stream needs to be consumed immediately then a {@link CommandHandler} can be attached to the stream; the stream,
 *     in turn, will notify the handler for every command that has been pushed;
 *     if the stream can be consumed after the actual compilation there's no need to attach a {@link CommandHandler}, as the
 *     {@link Command}s that were written to the stream can be replayed in the exact order in which they have been pushed.
 * 
 */
@ProviderType
public interface CommandStream {

    /**
     * Registers a listening {@link CommandHandler} to the stream. The {@link CommandHandler} will be notified for every new {@link
     * Command}
     * pushed to this stream.
     *
     * @param handler the handler to attach to this stream
     */
    void addHandler(CommandHandler handler);

    /**
     * Returns the {@link List} of commands that were written into this stream.
     *
     * @return the commands written into this stream
     */
    List getCommands();

}