io.maxthomas.dictum.lid.ValidISO3Languages.java Source code

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Here is the source code for io.maxthomas.dictum.lid.ValidISO3Languages.java

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/*
 * Copyright 2016 Max Thomas. All rights reserved.
 * See LICENSE in the project root directory.
 */
package io.maxthomas.dictum.lid;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import java.util.Optional;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.collect.ImmutableMap;

/**
 * Load a .json file of ISO3 languages. Syntax is as follows:
 * <br>
 * <pre>
 *   [
 *     { 'abbr' : 'foo',
 *       'name' : 'fooooooo' } ,
 *     ...
 *   ]
 * </pre>
 * <br>
 * Everything is nastily loaded in a static block. As long as the resource
 * is present, this should be OK.
 */
public class ValidISO3Languages {
    private static final String isoFileNameStr = "iso-639-3.json";
    public static final ObjectMapper om = new ObjectMapper();

    private static final ImmutableMap<String, String> iso3AbbrNameMap;
    static {
        try (InputStream is = ClassLoader.getSystemResourceAsStream(isoFileNameStr);) {
            try {
                List<ISO3AbbreviationNameBean> beanList = om.readValue(is,
                        new TypeReference<List<ISO3AbbreviationNameBean>>() {
                        });
                ImmutableMap.Builder<String, String> mb = new ImmutableMap.Builder<>();
                for (ISO3AbbreviationNameBean b : beanList)
                    mb.put(b.code, b.name);
                iso3AbbrNameMap = mb.build();
            } catch (IOException e) {
                // unlikely to throw given resource does not change.
                throw new RuntimeException("Failed to deserialize resource.");
            }
        } catch (IOException e) {
            // shall not throw unless resource is removed.
            throw new RuntimeException(
                    "Failed to load resource: " + isoFileNameStr + "; this program cannot run without it.");
        }
    }

    /**
     *
     * @param abbr
     *          a {@link String} representing a possible ISO3 abbreviation
     * @return <code>true</code> if a valid identifier
     */
    public static final boolean isValidISO3Abbreviation(final String abbr) {
        return iso3AbbrNameMap.containsKey(abbr);
    }

    /**
     *
     * @param abbr
     *          a {@link String} representing a possible ISO3 abbreviation
     * @return {@link Optional#empty()} if not present, otherwise, an
     *         {@link Optional} {@link String} wrapping the value
     */
    public static final Optional<String> getName(final String abbr) {
        return isValidISO3Abbreviation(abbr) ? Optional.of(iso3AbbrNameMap.get(abbr)) : Optional.empty();
    }
}