com.talvish.tales.serialization.json.translators.JsonElementToStringToChainTranslator.java Source code

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Here is the source code for com.talvish.tales.serialization.json.translators.JsonElementToStringToChainTranslator.java

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// ***************************************************************************
// *  Copyright 2012 Joseph Molnar
// *
// *  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 com.talvish.tales.serialization.json.translators;

import com.google.common.base.Preconditions;
import com.google.gson.JsonElement;
import com.google.gson.JsonNull;
import com.talvish.tales.parts.translators.TranslationException;
import com.talvish.tales.parts.translators.Translator;

/**
 * A translator that calls .getAsString on the object to translate before passing to 
 * another translator.
 * @author jmolnar
 *
 */
public class JsonElementToStringToChainTranslator implements Translator {
    private final Translator chainedTranslator;

    /**
     * Constructor taking the translator used to translate the underlying object, which is translated as a string first.
     * @param theChainedTranslator
     */
    public JsonElementToStringToChainTranslator(Translator theChainedTranslator) {
        Preconditions.checkNotNull(theChainedTranslator, "need the chained translator");
        chainedTranslator = theChainedTranslator;
    }

    /**
     * Translates the object as a string first and then into the chained translator.
     */
    @Override
    public Object translate(Object anObject) {
        Object returnValue;
        if (anObject == null || anObject.equals(JsonNull.INSTANCE)) {
            returnValue = chainedTranslator.translate(null);
        } else {
            try {
                returnValue = chainedTranslator.translate(((JsonElement) anObject).getAsString());
            } catch (ClassCastException | IllegalStateException | UnsupportedOperationException e) {
                throw new TranslationException(e);
            }
        }
        return returnValue;
    }
}