com.varmateo.yawg.util.SimpleMap Maven / Gradle / Ivy

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/**************************************************************************
 *
 * Copyright (c) 2016-2020 Yawg project contributors.
 *
 **************************************************************************/

package com.varmateo.yawg.util;

import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.Set;

import com.varmateo.yawg.api.YawgException;


/**
 * Wrapper for an unmodifiable map with utility methods for retrieving
 * values.
 */
public final class SimpleMap {


    private final Map _map;


    /**
     * Initializes this simple map with the given map.
     *
     * As a matter of optimization we assume the given map will
     * never be modified. It is up to the caller to ensure no changes
     * are performed in the givan map.
     *
     * @param map The map to be wrapped by this simple map.
     */
    public SimpleMap(final Map map) {

        _map = Objects.requireNonNull(map);
    }


    /**
     * Fetches a view on the contents of this simple map as an
     * unmodifiable map.
     *
     * @return A unmodifiable view of the contents of this simple map.
     */
    public Map asMap() {

        return Collections.unmodifiableMap(_map);
    }


    /**
     *
     */
    public  Optional get(
            final String key,
            final Class klass) {

        final T value = getWithType(key, klass);

        return Optional.ofNullable(value);
    }


    /**
     *
     */
    public Optional getString(final String key) {

        return get(key, String.class);
    }


    /**
     *
     */
    public Optional getMap(final String key) {

        @SuppressWarnings("unchecked")
        final Map value = (Map) getWithType(key, Map.class);

        return Optional.ofNullable(value)
                .map(SimpleMap::new);
    }


    /**
     *
     */
    public  Optional> getList(
            final String key,
            final Class itemsClass) {

        @SuppressWarnings("unchecked")
        final List