org.eclipse.xtext.xbase.lib.Inline Maven / Gradle / Ivy

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/*******************************************************************************
 * Copyright (c) 2012 itemis AG (http://www.itemis.eu) and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *******************************************************************************/
package org.eclipse.xtext.xbase.lib;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtCompatible;

/**
 * Allows to describe how a certain static function should be inlined by the Xbase compiler.
 * 
 * @author Sebastian Zarnekow - Initial contribution and API
 * @since 2.3
 */
@Beta
@Retention(RetentionPolicy.RUNTIME)
@Target(value = { ElementType.METHOD })
@GwtCompatible public @interface Inline {

	/**
	 * The inline format string. Placeholders like {@code $1, $2} etc can be used where the {@code 1..n} parameters of
	 * the inlined method are used for {@code $1} to {@code $n} and the {@link #imported()} types are used for
	 * subsequent indices. The next index {@code $n} can be used to insert all type parameters of the original
	 * declaration. And finally the last indices refer to the upper bound substitute of the type parameters individually.
	 * 
	 * So the order is arguments, imports, all type parameters at once incl. brackets and upper bounds of the individual type parameters without brackets
	 * 
	 * Example:
	 * 
	 * For the following signatures
	 * 
	 *   @Inline(value=".." imported = BigDecimal.class)
	 *   public void  myMethod(String p1, String p2) { ... }
	 * 
	 * $1 refers to p1
	 * $2 refers to p2
	 * $3 refers to BigDecimal
	 * $4 refers to 
	 * $5 refers to the upper bound of T1
	 * $6 refers to the upper bound of T2
	 * 
	 */
	String value();

	/**
	 * Types that should be imported to inline the operation.
	 */
	Class[] imported() default {};

	/**
	 * whether the inlined expression is a statement expression (see 14.8 - Statement Expressions in
	 * Java Language Specification, Third Edition )
	 */
	boolean statementExpression() default false;

}