de.cosmocode.json.JsonArrayList.java Source code

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Here is the source code for de.cosmocode.json.JsonArrayList.java

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/**
 * Copyright 2010 CosmoCode GmbH
 *
 * 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 de.cosmocode.json;

import java.util.List;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import de.cosmocode.collections.utility.AbstractUtilityList;
import de.cosmocode.patterns.Adapter;

/**
 * An {@link Adapter} providing
 * a {@link List}-view on a {@link JSONArray}.
 *
 * See also {@link JSON#asList(JSONArray)}.
 * 
 * @author schoenborn@cosmocode.de
 */
@Adapter(List.class)
final class JsonArrayList extends AbstractUtilityList<Object> {

    private static final Object NULL = null;

    private final JSONArray array;

    /**
     * Constructs a new {@link JsonArrayList} using the specified {@link JSONArray}.
     * 
     * @param array the {@link JSONArray} this list will be backed by
     */
    public JsonArrayList(JSONArray array) {
        if (array == null)
            throw new NullPointerException("JSONArray must not be null");
        this.array = array;
        if (contains(null))
            throw new NullPointerException("JSONList must not contain null values");
    }

    @Override
    public Object get(int index) {
        if (index < 0 || index >= size())
            throw new IndexOutOfBoundsException("Index: " + index + ", Size: " + size());
        final Object value = array.opt(index);
        if (value instanceof JSONObject) {
            final JSONObject json = JSONObject.class.cast(value);
            return JSON.asMap(json);
        } else if (value instanceof JSONArray) {
            final JSONArray json = JSONArray.class.cast(value);
            return JSON.asList(json);
        } else if (value == null || value.equals(NULL)) {
            return null;
        } else {
            return value;
        }
    }

    @Override
    public Object set(int index, Object element) {
        if (index < 0 || index >= size())
            throw new IndexOutOfBoundsException("Index: " + index + ", Size: " + size());
        if (element == null)
            throw new NullPointerException("Element must not be null");
        try {
            final Object oldValue = get(index);
            array.put(index, element);
            return oldValue;
        } catch (JSONException e) {
            throw new IllegalArgumentException(e);
        }
    }

    @Override
    public void add(int index, Object element) {
        if (index < 0 || index > size())
            throw new IndexOutOfBoundsException("Index: " + index + ", Size: " + size());
        if (element == null)
            throw new NullPointerException("Element must not be null");

        // save current position
        int i = index;

        // holds the next element
        Object next = element;

        // loop until the end
        while (true) {
            // is the current index after the last element?
            if (i == size()) {
                // just add the next element
                array.put(next);
                // stop looping after adding next element to the end
                break;
            } else {
                // we didn't reach the end, so just overwrite
                // the element at position i, save the overwritten one
                // and increase the index
                next = set(i++, next);
            }
        }
    }

    @Override
    public Object remove(int index) {
        throw new UnsupportedOperationException("Unable to delegate to JSONArray");
    }

    @Override
    public int size() {
        return array.length();
    }

    @Override
    public String toString() {
        return array.toString();
    }

}