org.eobjects.analyzer.beans.api.Distributed Maven / Gradle / Ivy
/**
* eobjects.org AnalyzerBeans
* Copyright (C) 2010 eobjects.org
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.eobjects.analyzer.beans.api;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Inherited;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import org.eobjects.analyzer.result.AnalyzerResult;
import org.eobjects.analyzer.result.AnalyzerResultReducer;
/**
* Annotation used to override the default component distribution and clustering
* model. Any component (transformer, filter or analyzer) with this annotation
* can define whether or not it can be distributed in a server cluster or not. A
* distributed component will have multiple instances, all with the same
* configuration. But since there are more instances, naturally they need to be
* either stateless or have a state-logic which supports separate execution.
*
* The default behaviour of the components is:
*
*
* - Transformers and Filters are by default distributed. The rationale behind
* this default value is that the invoked methods (transform(...) and
* categorize(...)) both return their results immidiately and thus a stateless
* implementation will be the normal scenario.
* - Analyzers are by default not distributed. The rationale behind
* this default value is that analyzers are expected to build up it's result
* during execution and thus will typically be stateful. If a Analyzer is to be
* distributed, it needs, or it's {@link AnalyzerResult} class needs, to specify
* a {@link AnalyzerResultReducer} value for the {@link #reducer()} field.
*
*
* @see FilterBean
* @see TransformerBean
* @see AnalyzerBean
*/
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
@Inherited
@Documented
public @interface Distributed {
/**
* Determines whether or not the component with this annotation is
* distributable.
*
* @return a boolean indicating whether or not distributed execution of the
* component is allowed.
*/
public boolean value() default true;
/**
* Gets a reducer class for {@link AnalyzerResult}s generated by this
* component (applies to Analyzer or AnalyzerResult classes only).
*
* @return a reducer class for results generated by this component.
*/
public Class> reducer() default NoAnalyzerResultReducer.class;
}