Java List Single Value singleValue(Class type, List values)

Description

single Value

License

Open Source License

Parameter

Parameter	Description
T	a parameter
type	a parameter
values	a parameter

Declaration

public final static <T> T singleValue(Class<T> type, List<?> values) 

Method Source Code

//package com.java2s;
/*/* w  w w.j ava2s.  co  m*/
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * 
 * Copyright (c) 2013-2020 Madz. All rights reserved.
 * 
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License"). You
 * may not use this file except in compliance with the License. You can
 * obtain a copy of the License at
 * https://raw.github.com/zhongdj/Lifecycle/master/License.txt
 * . See the License for the specific
 * language governing permissions and limitations under the License.
 * 
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at packager/legal/LICENSE.txt.
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 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
 * "Portions Copyright [year] [name of copyright owner]"
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 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license." If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above. However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
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import java.util.Collection;

import java.util.List;

public class Main {
    /**
     * @param <T>
     * @param type
     * @param values
     * @return
     */
    public final static <T> T singleValue(Class<T> type, List<?> values) {
        if (null == values || values.size() != 1) {
            throw new IllegalStateException("Expecting a single value");
        }
        return type.cast(values.get(0));
    }

    /**
     * @param <T>
     * @param type
     * @param values
     * @return
     */
    public final static <T> T singleValue(Class<T> type, Collection<?> values) {
        if (null == values || values.size() != 1) {
            throw new IllegalStateException("Expecting a single value of type " + type.getSimpleName());
        }
        return type.cast(values.iterator().next());
    }
}

Related

1. singleItemAsList(T item)
2. singleQuoatanizeStringList(List entries)
3. singletonList(final T source)
4. singletonList(T element)
5. singletonListIfNotNullOrEmptyListIfNull(T element)
6. singleValue(List l)
7. singleValue(List values)