/*
 * Copyright 2013 MovingBlocks
 *
 * 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.terasology.persistence.typeHandling.extensionTypes;

import org.terasology.assets.Asset;
import org.terasology.asset.Assets;
import org.terasology.persistence.typeHandling.StringRepresentationTypeHandler;

import java.util.Optional;

/**
 * @author Immortius
 */
public class AssetTypeHandler<T extends Asset> extends StringRepresentationTypeHandler<T> {
    private Class<T> assetClass;

    public AssetTypeHandler(Class<T> assetClass) {
        this.assetClass = assetClass;
    }

    @Override
    public String getAsString(T item) {
        if (item == null) {
            return "";
        }
        return item.getUrn().toString();
    }

    @Override
    public T getFromString(String representation) {
        Optional<T> asset = Assets.get(representation, assetClass);
        if (asset.isPresent()) {
            return assetClass.cast(asset.get());
        }
        return null;
    }
}

/*
 * Copyright 2013 MovingBlocks
 *
 * 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.terasology.persistence.typeHandling.extensionTypes;

import com.google.common.base.Strings;
import org.terasology.asset.Assets;
import org.terasology.assets.Asset;
import org.terasology.persistence.typeHandling.StringRepresentationTypeHandler;

import java.util.Optional;

/**
 * @author Immortius
 */
public class AssetTypeHandler<T extends Asset> extends StringRepresentationTypeHandler<T> {
    private Class<T> assetClass;

    public AssetTypeHandler(Class<T> assetClass) {
        this.assetClass = assetClass;
    }

    @Override
    public String getAsString(T item) {
        if (item == null) {
            return "";
        }
        return item.getUrn().toString();
    }

    @Override
    public T getFromString(String representation) {
        if (Strings.isNullOrEmpty(representation)) {
            return null;
        }
        Optional<T> asset = Assets.get(representation, assetClass);
        if (asset.isPresent()) {
            return assetClass.cast(asset.get());
        }
        return null;
    }
}

Allow components to have empty assets fields.