/*

 * Copyright (c) 1999, 2015, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * 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.

 *

 * 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).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package jdk.javadoc.internal.doclets.toolkit.util;

import java.util.*;

import javax.lang.model.element.ExecutableElement;

import javax.lang.model.element.TypeElement;

import javax.lang.model.type.TypeMirror;

import jdk.javadoc.internal.doclets.toolkit.Configuration;

/**

 * For a given class method, build an array of interface methods which it

 * implements.

 *

 *  <p><b>This is NOT part of any supported API.

 *  If you write code that depends on this, you do so at your own risk.

 *  This code and its internal interfaces are subject to change or

 *  deletion without notice.</b>

 *

 * @author Atul M Dambalkar

 */

public class ImplementedMethods {

    private final Map<ExecutableElement, TypeMirror> interfaces = new HashMap<>();

    private final List<ExecutableElement> methlist = new ArrayList<>();

    private final Utils utils;

    private final TypeElement typeElement;

    private final ExecutableElement method;

    public ImplementedMethods(ExecutableElement method, Configuration configuration) {

        this.method = method;

        this.utils = configuration.utils;

        typeElement = utils.getEnclosingTypeElement(method);

    }

    /**

     * Return the array of interface methods which the method passed in the

     * constructor is implementing. The search/build order is as follows:

     * <pre>

     * 1. Search in all the immediate interfaces which this method's class is

     *    implementing. Do it recursively for the superinterfaces as well.

     * 2. Traverse all the superclasses and search recursively in the

     *    interfaces which those superclasses implement.

     *</pre>

     *

     * @return SortedSet<ExecutableElement> of implemented methods.

     */

    public List<ExecutableElement> build() {

        buildImplementedMethodList();

        return methlist;

    }

    public TypeMirror getMethodHolder(ExecutableElement ee) {

        return interfaces.get(ee);

    }

    /**

     * Search for the method in the array of interfaces. If found check if it is

     * overridden by any other subinterface method which this class

     * implements. If it is not overidden, add it in the method list.

     * Do this recursively for all the extended interfaces for each interface

     * from the array passed.

     */

    private void buildImplementedMethodList() {

        Set<TypeMirror> intfacs = utils.getAllInterfaces(typeElement);

        for (TypeMirror interfaceType : intfacs) {

            ExecutableElement found = utils.findMethod(utils.asTypeElement(interfaceType), method);

            if (found != null) {

                removeOverriddenMethod(found);

                if (!overridingMethodFound(found)) {

                    methlist.add(found);

                    interfaces.put(found, interfaceType);

                }

            }

        }

    }

    /**

     * Search in the method list and check if it contains a method which

     * is overridden by the method as parameter.  If found, remove the

     * overridden method from the method list.

     *

     * @param method Is this method overriding a method in the method list.

     */

    private void removeOverriddenMethod(ExecutableElement method) {

        TypeElement overriddenClass = utils.overriddenClass(method);

        if (overriddenClass != null) {

            for (int i = 0; i < methlist.size(); i++) {

                TypeElement te = utils.getEnclosingTypeElement(methlist.get(i));

                if (te == overriddenClass || utils.isSubclassOf(overriddenClass, te)) {

                    methlist.remove(i);  // remove overridden method

                    return;

                }

            }

        }

    }

    /**

     * Search in the already found methods' list and check if it contains

     * a method which is overriding the method parameter or is the method

     * parameter itself.

     *

     * @param method MethodDoc Method to be searched in the Method List for

     * an overriding method.

     */

    private boolean overridingMethodFound(ExecutableElement method) {

        TypeElement containingClass = utils.getEnclosingTypeElement(method);

        for (ExecutableElement listmethod : methlist) {

            if (containingClass == utils.getEnclosingTypeElement(listmethod)) {

                // it's the same method.

                return true;

            }

            TypeElement te = utils.overriddenClass(listmethod);

            if (te == null) {

                continue;

            }

            if (te == containingClass || utils.isSubclassOf(te, containingClass)) {

                return true;

            }

        }

        return false;

    }

}