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Groovy: A powerful, dynamic language for the JVM
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/*
 * Copyright 2003-2013 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package groovy.transform.stc;

import org.codehaus.groovy.ast.ASTNode;
import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.MethodNode;
import org.codehaus.groovy.control.CompilationUnit;
import org.codehaus.groovy.control.SourceUnit;

/**
 * A hint used to instruct the type checker to pick the first parameter type. For example:
 * public <T> def doWith(T src, @ClosureParams(FirstParam.class) Closure c) { c.call(src); }
 *
 * This class has several inner classes that also helps picking generic argument types instead of the parameter type.
 *
 * @author Cédric Champeau
 * @since 2.3.0
 */
public class FirstParam extends PickAnyArgumentHint {
    public FirstParam() {
        super(0,-1);
    }

    /**
     * A hint used to instruct the type checker to pick the first generic type of the first parameter type. For example:
     * void <T> doWithElements(List<T> src, @ClosureParams(FirstParam.FirstGenericType.class) Closure c) { src.each { c.call(it) } }
     *
     * @author Cédric Champeau
     * @since 2.3.0
     */
    public static class FirstGenericType extends PickAnyArgumentHint {
        public FirstGenericType() {
            super(0,0);
        }
    }

    /**
     * A hint used to instruct the type checker to pick the second generic type of the first parameter type. For example:
     * void <T,U> doWithElements(Tuple<T,U> src, @ClosureParams(FirstParam.SecondGenericType.class) Closure c) { src.each { c.call(it) } }
     *
     * @author Cédric Champeau
     * @since 2.3.0
     */
    public static class SecondGenericType extends PickAnyArgumentHint {
        public SecondGenericType() {
            super(0,1);
        }
    }

    /**
     * A hint used to instruct the type checker to pick the third generic type of the first parameter type. For example:
     * void <T,U,V> doWithElements(Triple<T,U,V> src, @ClosureParams(FirstParam.ThirdGenericType.class) Closure c) { src.each { c.call(it) } }
     *
     * @author Cédric Champeau
     * @since 2.3.0
     */
    public static class ThirdGenericType extends PickAnyArgumentHint {
        public ThirdGenericType() {
            super(0,2);
        }
    }

    /**
     * A hint used to instruct the type checker to pick the type of the component of the first parameter type, which is therefore
     * expected to be an array, like in this example:
     * void <T> doWithArray(T[] array, @ClosureParams(FirstParam.Component.class) Closure c) { array.each { c.call(it)} }
     */
    public static class Component extends FirstParam {
        @Override
        public ClassNode[] getParameterTypes(final MethodNode node, final String[] options, final SourceUnit sourceUnit, final CompilationUnit unit, final ASTNode usage) {
            final ClassNode[] parameterTypes = super.getParameterTypes(node, options, sourceUnit, unit, usage);
            parameterTypes[0] = parameterTypes[0].getComponentType();
            return parameterTypes;
        }
    }
}