com.lyncode.jtwig.functions.internal.list.Join Maven / Gradle / Ivy

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/**
 * Copyright 2012 Lyncode
 *
 * 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.lyncode.jtwig.functions.internal.list;

import com.lyncode.jtwig.functions.JtwigFunction;
import com.lyncode.jtwig.functions.annotations.JtwigFunctionDeclaration;
import com.lyncode.jtwig.functions.exceptions.FunctionException;
import org.apache.commons.lang3.StringUtils;

import static com.lyncode.jtwig.functions.util.Requirements.between;
import static com.lyncode.jtwig.functions.util.Requirements.requires;

@JtwigFunctionDeclaration(name = "join")
public class Join implements JtwigFunction {
    @Override
    public Object execute(Object... arguments) throws FunctionException {
        requires(arguments)
                .withNumberOfArguments(between(1, 2));

        String separator = "";
        if (arguments.length == 2)
            separator = arguments[1].toString();

        if (arguments[0] == null)
            return "";
        else if (arguments[0] instanceof Iterable)
            return StringUtils.join((Iterable) arguments[0], separator);
        else if (arguments[0].getClass().isArray())
            return StringUtils.join((Object[]) arguments[0], separator);
        else throw new FunctionException("First arguments must be a list or an array.");
    }
}