org.trnltk.common.structure.StringEnumMap.java Source code

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Here is the source code for org.trnltk.common.structure.StringEnumMap.java

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/*
 * Copyright  2013  Ali Ok (aliokATapacheDOTorg)
 *
 *  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.
 */

package org.trnltk.common.structure;

import com.google.common.base.Function;
import com.google.common.base.Strings;
import com.google.common.collect.Collections2;
import com.google.common.collect.ImmutableMap;

import java.util.Collection;
import java.util.Collections;

/**
 * This is a convenience class for enums that also are represented with strings.
 * This classes can be useful for loading enum values from textual data.
 *
 * @param <T>
 */
public class StringEnumMap<T extends StringEnum> {
    private final ImmutableMap<String, T> map;
    private final Class<T> clazz;

    private StringEnumMap(Class<T> clazz) {
        this.clazz = clazz;
        final ImmutableMap.Builder<String, T> mapBuilder = new ImmutableMap.Builder<String, T>();
        for (T senum : clazz.getEnumConstants()) {
            mapBuilder.put(senum.getStringForm(), senum);
        }
        this.map = mapBuilder.build();
    }

    public static <T extends StringEnum> StringEnumMap<T> get(Class<T> clazz) {
        return new StringEnumMap<T>(clazz);
    }

    public T getEnum(String s) {
        if (Strings.isNullOrEmpty(s))
            throw new IllegalArgumentException("Input String must have content.");
        T res = map.get(s);
        if (res == null)
            throw new IllegalArgumentException(
                    "Cannot find a representation of :" + s + " for enum class:" + clazz.getName());
        return res;
    }

    public Collection<T> getEnums(Collection<String> strs) {
        if (strs == null || strs.isEmpty())
            return Collections.emptyList();
        else
            return Collections2.transform(strs, new Function<String, T>() {
                @Override
                public T apply(String input) {
                    return getEnum(input);
                }
            });
    }

    @SuppressWarnings("UnusedDeclaration")
    public boolean enumExists(String s) {
        return map.containsKey(s);
    }
}