sparksoniq.jsoniq.runtime.iterator.functions.strings.ConcatFunctionIterator Maven / Gradle / Ivy

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 *
 * Authors: Stefan Irimescu, Can Berker Cikis
 *
 */

package sparksoniq.jsoniq.runtime.iterator.functions.strings;

import sparksoniq.exceptions.IteratorFlowException;
import sparksoniq.exceptions.UnexpectedTypeException;
import sparksoniq.jsoniq.item.ItemFactory;
import sparksoniq.jsoniq.runtime.iterator.RuntimeIterator;
import sparksoniq.jsoniq.runtime.iterator.functions.base.LocalFunctionCallIterator;
import sparksoniq.jsoniq.runtime.metadata.IteratorMetadata;

import java.util.List;

import org.rumbledb.api.Item;

public class ConcatFunctionIterator extends LocalFunctionCallIterator {

	private static final long serialVersionUID = 1L;

	public ConcatFunctionIterator(List arguments, IteratorMetadata iteratorMetadata) {
        super(arguments, iteratorMetadata);
    }

    @Override
    public Item next() {
        if (this._hasNext) {
            StringBuilder builder = new StringBuilder("");
            for (RuntimeIterator iterator : this._children) {
                Item item = this.getSingleItemOfTypeFromIterator(iterator, Item.class);
                // if not empty sequence
                if (item != null) {
                    String stringValue = "";
                    if (item.isAtomic()) {
                        stringValue = item.serialize();       // for atomic items (not array or object) returns the equivalent string value
                    } else {
                        throw new UnexpectedTypeException("String concat function has arguments that can't be converted to a string " +
                                item.serialize(), getMetadata());
                    }
                    if (stringValue != "") {
                        builder.append(stringValue);
                    }
                }
            }
            this._hasNext = false;
            return ItemFactory.getInstance().createStringItem(builder.toString());
        } else
            throw new IteratorFlowException(RuntimeIterator.FLOW_EXCEPTION_MESSAGE + " substring function", getMetadata());
    }
}