Java Collection Search indexOfObjectIdentity(Collection collection, Object object)

Description

Returns the index position of the first occurring object within the Collection .

License

Apache License

Parameter

Parameter	Description
collection	a parameter
object	a parameter

Return

index position of the first matching element;-1 if no element is matching

Declaration

public static <E> int indexOfObjectIdentity(Collection<E> collection, Object object) 

Method Source Code

//package com.java2s;
/*******************************************************************************
 * Copyright 2011 Danny Kunz//from www  . j av a 2 s . c  om
 * 
 * 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.
 ******************************************************************************/

import java.util.Collection;
import java.util.Iterator;

public class Main {
    /**
     * Returns the index position of the first occurring object within the {@link Collection}. Comparisons uses the
     * "object == element" instead of the "equals" method to determine the object identity.
     * 
     * @param collection
     * @param object
     * @return index position of the first matching element;-1 if no element is matching
     */
    public static <E> int indexOfObjectIdentity(Collection<E> collection, Object object) {
        //
        int retval = -1;

        //
        if (collection != null) {
            Iterator<E> iterator = collection.iterator();
            if (iterator != null) {
                int indexPosition = 0;
                while (retval < 0 && iterator.hasNext()) {
                    //
                    E element = iterator.next();
                    if (element == object) {
                        retval = indexPosition;
                    }

                    //
                    indexPosition++;
                }
            }
        }

        //
        return retval;
    }
}

Related

1. hasValidElement(Collection collection)
2. hasValue(Collection collection)
3. indexOf(Collection stringCollection, String str)
4. indexOf(final Collection c, final Object elem)
5. indexOfInstance(final Collection collection, final T instance)