core/sis-utility/src/main/java/org/apache/sis/internal/jdk9/JDK9.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.sis.internal.jdk9;

import java.nio.Buffer;
import java.nio.ByteBuffer;
import java.nio.DoubleBuffer;
import java.nio.FloatBuffer;
import java.nio.IntBuffer;
import java.nio.LongBuffer;
import java.nio.ShortBuffer;
import java.util.Arrays;
import java.util.Set;
import java.util.List;
import java.util.Collections;
import java.util.LinkedHashSet;
import org.apache.sis.internal.util.UnmodifiableArrayList;


/**
 * Place holder for some functionalities defined only in JDK9.
 * This file will be deleted on the SIS JDK9 branch.
 *
 * @author  Martin Desruisseaux (Geomatys)
 * @since   1.1
 * @version 0.8
 * @module
 */
public final class JDK9 {
    /**
     * Do not allow instantiation of this class.
     */
    private JDK9() {
    }

    /**
     * Placeholder for {@code List.of(...)}.
     *
     * @param  <E>       type of elements.
     * @param  elements  the elements to put in an unmodifiable list.
     * @return an unmodifiable list of the given elements.
     */
    @SafeVarargs
    public static <E> List<E> listOf(final E... elements) {
        switch (elements.length) {
            case 0:  return Collections.emptyList();
            case 1:  return Collections.singletonList(elements[0]);
            default: return UnmodifiableArrayList.wrap(elements);
        }
    }

    /**
     * Placeholder for {@code Set.of(...)}.
     *
     * @param  <E>       type of elements.
     * @param  elements  the elements to put in an unmodifiable set.
     * @return an unmodifiable set of the given elements.
     */
    @SafeVarargs
    public static <E> Set<E> setOf(final E... elements) {
        switch (elements.length) {
            case 0:  return Collections.emptySet();
            case 1:  return Collections.singleton(elements[0]);
            default: return Collections.unmodifiableSet(new LinkedHashSet<>(Arrays.asList(elements)));
        }
    }

    /**
     * Place holder for {@code Buffer.slice()}.
     *
     * @param  b the buffer to slice.
     * @return the sliced buffer.
     */
    public static Buffer slice(Buffer b) {
        if (b instanceof ByteBuffer)   return ((ByteBuffer) b).slice();
        if (b instanceof ShortBuffer)  return ((ShortBuffer) b).slice();
        if (b instanceof IntBuffer)    return ((IntBuffer) b).slice();
        if (b instanceof LongBuffer)   return ((LongBuffer) b).slice();
        if (b instanceof FloatBuffer)  return ((FloatBuffer) b).slice();
        if (b instanceof DoubleBuffer) return ((DoubleBuffer) b).slice();
        throw new IllegalArgumentException();
    }

    /**
     * Place holder for {@code Buffer.duplicate()}.
     *
     * @param  b the buffer to duplicate.
     * @return the duplicate buffer.
     */
    public static Buffer duplicate(Buffer b) {
        if (b instanceof ByteBuffer)   return ((ByteBuffer) b).duplicate();
        if (b instanceof ShortBuffer)  return ((ShortBuffer) b).duplicate();
        if (b instanceof IntBuffer)    return ((IntBuffer) b).duplicate();
        if (b instanceof LongBuffer)   return ((LongBuffer) b).duplicate();
        if (b instanceof FloatBuffer)  return ((FloatBuffer) b).duplicate();
        if (b instanceof DoubleBuffer) return ((DoubleBuffer) b).duplicate();
        throw new IllegalArgumentException();
    }

    /**
     * Place holder for {@code Class.getPackageName()}.
     *
     * @param  c  the class for which to get the package name.
     * @return the name of the package.
     */
    public static String getPackageName(Class<?> c) {
        Class<?> outer;
        while ((outer = c.getEnclosingClass()) != null) {
            c = outer;
        }
        String name = c.getName();
        final int separator = name.lastIndexOf('.');
        name = (separator >= 1) ? name.substring(0, separator) : "";
        return name;
    }
}