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/*
 * Copyright 2010-2012 Craig S. Dickson (http://craigsdickson.com)
 *
 * 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 com.squeakysand.commons.lang;

import java.util.Collection;
import java.util.List;
import java.util.Set;

import org.apache.commons.collections.CollectionUtils;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ClassHelper {

    private static final Logger LOG = LoggerFactory.getLogger(ClassHelper.class);

    public static Class getCommonAncestorClass(Class c1, Class c2) {
        LOG.trace("invoked with: {}, {}", c1, c2);
        ClassMetaInfo c1metaInfo = new ClassMetaInfo(c1);
        ClassMetaInfo c2metaInfo = new ClassMetaInfo(c2);
        List> c1hierarchy = c1metaInfo.getClassHierarchy();
        List> c2hierarchy = c2metaInfo.getClassHierarchy();
        Class result = null;
        for (int i = 0; i < c1hierarchy.size() && i < c2hierarchy.size(); i++) {
            Class c1ancestor = c1hierarchy.get(i);
            Class c2ancestor = c2hierarchy.get(i);
            if (c1ancestor.equals(c2ancestor)) {
                result = c1ancestor;
            } else {
                break;
            }
        }
        LOG.trace("result: {}", result);
        return result;
    }

    public static Collection> getCommonInterfaces(Class c1, Class c2) {
        LOG.trace("invoked with: {}, {}", c1, c2);
        ClassMetaInfo c1metaInfo = new ClassMetaInfo(c1);
        ClassMetaInfo c2metaInfo = new ClassMetaInfo(c2);
        Set> c1interfaces = c1metaInfo.getImplementedInterfaces();
        Set> c2interfaces = c2metaInfo.getImplementedInterfaces();
        Collection> result = CollectionUtils.intersection(c1interfaces, c2interfaces);
        LOG.trace("result: {}", ToStringHelper.toString(result));
        return result;
    }

    public static boolean classesImplementCommonInterface(Class commonInterface, Class... classes) {
        if (commonInterface == null) {
            throw new IllegalArgumentException("i cannot be null");
        }
        if (!commonInterface.isInterface()) {
            throw new IllegalArgumentException("i must be an interface type");
        }
        if (classes == null || classes.length == 0) {
            throw new IllegalArgumentException("must pass at least 1 class to test against");
        }
        LOG.trace("invoked with: i = {}, classes = {}", commonInterface, ToStringHelper.toString(classes));
        boolean result = true;
        for (Class klass : classes) {
            if (!commonInterface.isAssignableFrom(klass)) {
                result = false;
                break;
            }
        }
        LOG.trace("result: {}", result);
        return result;
    }

}