org.openjdk.jmh.annotations.Param Maven / Gradle / Ivy

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 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
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 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
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package org.openjdk.jmh.annotations;

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;

/**
 * Marks the configurable parameter in the benchmark.
 *
 * {@link Param} fields should be non-final fields,
 * and should only reside in {@link State} classes. JMH will inject
 * the value into the annotated field before any {@link Setup} method
 * is called. It is not guaranteed the field value would be accessible
 * in any initializer or any constructor of {@link State}.
 *
 * Parameters are acceptable on any primitive type, primitive wrapper type,
 * a String, or an Enum. The annotation value is given in String, and will be
 * coerced as required to match the field type.
 *
 * Parameters should normally provide the default values which make
 * benchmark runnable even without the explicit parameters set for the run.
 * The only exception is {@link Param} over {@link java.lang.Enum}, which
 * will implicitly have the default value set encompassing all enum constants.
 *
 * When multiple {@link Param}-s are needed for the benchmark run,
 * JMH will compute the outer product of all the parameters in the run.
 */
@Inherited
@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
public @interface Param {

    String BLANK_ARGS = "blank_blank_blank_2014";

    /**
     * Default values sequence for the parameter. By default, the parameter
     * values will be traversed during the run in the given order.
     *
     * @return values sequence to follow.
     */
    String[] value() default { BLANK_ARGS };

}