Main.java Source code

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Here is the source code for Main.java

Source

//package com.java2s;
/**
 * Copyright (C) 2014-2017 Philip Helger (www.helger.com)
 * philip[at]helger[dot]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.
 */

import java.util.List;

import java.util.function.Predicate;
import javax.annotation.Nonnegative;

import javax.annotation.Nullable;

public class Main {
    /**
     * Safe list element accessor method.
     *
     * @param aList
     *        The list to extract from. May be <code>null</code>.
     * @param nIndex
     *        The index to access. Should be &ge; 0.
     * @return <code>null</code> if the element cannot be accessed.
     * @param <ELEMENTTYPE>
     *        The type of elements on the list.
     */
    @Nullable
    public static <ELEMENTTYPE> ELEMENTTYPE getAtIndex(@Nullable final List<? extends ELEMENTTYPE> aList,
            final int nIndex) {
        return getAtIndex(aList, nIndex, null);
    }

    /**
     * Safe list element accessor method.
     *
     * @param aList
     *        The list to extract from. May be <code>null</code>.
     * @param nIndex
     *        The index to access. Should be &ge; 0.
     * @param aDefault
     *        The value to be returned, if the index is out of bounds.
     * @return The default parameter if the element cannot be accessed.
     * @param <ELEMENTTYPE>
     *        The type of elements on the list.
     */
    @Nullable
    public static <ELEMENTTYPE> ELEMENTTYPE getAtIndex(@Nullable final List<? extends ELEMENTTYPE> aList,
            final int nIndex, @Nullable final ELEMENTTYPE aDefault) {
        return aList != null && nIndex >= 0 && nIndex < aList.size() ? aList.get(nIndex) : aDefault;
    }

    @Nullable
    public static <ELEMENTTYPE> ELEMENTTYPE getAtIndex(@Nullable final Iterable<? extends ELEMENTTYPE> aCollection,
            @Nonnegative final int nIndex) {
        return getAtIndex(aCollection, nIndex, null);
    }

    @Nullable
    public static <ELEMENTTYPE> ELEMENTTYPE getAtIndex(@Nullable final Iterable<? extends ELEMENTTYPE> aCollection,
            @Nonnegative final int nIndex, @Nullable final ELEMENTTYPE aDefault) {
        if (nIndex >= 0) {
            int nCurIndex = 0;
            for (final ELEMENTTYPE aElement : aCollection) {
                if (nCurIndex == nIndex)
                    return aElement;
                ++nCurIndex;
            }
        }
        return aDefault;
    }

    @Nullable
    public static <ELEMENTTYPE> ELEMENTTYPE getAtIndex(@Nullable final Iterable<? extends ELEMENTTYPE> aCollection,
            @Nullable final Predicate<? super ELEMENTTYPE> aFilter, @Nonnegative final int nIndex) {
        return getAtIndex(aCollection, aFilter, nIndex, null);
    }

    @Nullable
    public static <ELEMENTTYPE> ELEMENTTYPE getAtIndex(@Nullable final Iterable<? extends ELEMENTTYPE> aCollection,
            @Nullable final Predicate<? super ELEMENTTYPE> aFilter, @Nonnegative final int nIndex,
            @Nullable final ELEMENTTYPE aDefault) {
        if (aFilter == null)
            return getAtIndex(aCollection, nIndex, aDefault);

        if (nIndex >= 0) {
            int nCurIndex = 0;
            for (final ELEMENTTYPE aElement : aCollection)
                if (aFilter.test(aElement)) {
                    if (nCurIndex == nIndex)
                        return aElement;
                    ++nCurIndex;
                }
        }
        return aDefault;
    }
}