net.signalr.client.json.jackson.JacksonElement.java Source code

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Here is the source code for net.signalr.client.json.jackson.JacksonElement.java

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/*
 * Copyright  Martin Tamme
 *
 * 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 net.signalr.client.json.jackson;

import net.signalr.client.json.JsonElement;
import net.signalr.client.json.JsonEmpty;
import net.signalr.client.json.JsonException;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

/**
 * Represents a Jackson based JSON element.
 */
public class JacksonElement implements JsonElement {

    /**
     * The object mapper.
     */
    private final ObjectMapper _mapper;

    /**
     * The underlying node.
     */
    private final JsonNode _node;

    /**
     * Initializes a new instance of the {@link JacksonElement} class.
     * 
     * @param mapper The object mapper.
     * @param node The underlying node.
     */
    public JacksonElement(final ObjectMapper mapper, final JsonNode node) {
        if (mapper == null) {
            throw new IllegalArgumentException("Mapper must not be null");
        }
        if (node == null) {
            throw new IllegalArgumentException("Node must not be null");
        }

        _mapper = mapper;
        _node = node;
    }

    @Override
    public boolean isArray() {
        return _node.isArray();
    }

    @Override
    public boolean isObject() {
        return _node.isObject();
    }

    @Override
    public boolean isValue() {
        return !_node.isArray() && !_node.isObject();
    }

    @Override
    public JsonElement get(final int index) {
        if (!_node.isArray()) {
            throw new IndexOutOfBoundsException(String.valueOf(index));
        }

        // Returns: Node that represent value of the specified element,
        // if this node is an array and has specified element.
        // Null otherwise.
        final JsonNode node = _node.get(index);

        if (node == null) {
            throw new IndexOutOfBoundsException(String.valueOf(index));
        }

        return new JacksonElement(_mapper, node);
    }

    @Override
    public JsonElement get(final String name) {
        if (name == null) {
            throw new IllegalArgumentException("Name must not be null");
        }

        if (!_node.isObject()) {
            return JsonEmpty.INSTANCE;
        }

        // Returns: Node that represent value of the specified field,
        // if this node is an object and has value for the specified field.
        // Null otherwise.
        final JsonNode node = _node.get(name);

        if (node == null) {
            return JsonEmpty.INSTANCE;
        }

        return new JacksonElement(_mapper, node);
    }

    @Override
    public boolean getBoolean(final boolean defaultValue) {
        if (!_node.isBoolean()) {
            return defaultValue;
        }

        return _node.asBoolean();
    }

    @Override
    public double getDouble(final double defaultValue) {
        if (!_node.isDouble()) {
            return defaultValue;
        }

        return _node.asDouble();
    }

    @Override
    public int getInt(final int defaultValue) {
        if (!_node.isInt()) {
            return defaultValue;
        }

        return _node.asInt();
    }

    @Override
    public long getLong(final long defaultValue) {
        if (!_node.isLong()) {
            return defaultValue;
        }

        return _node.asLong();
    }

    @Override
    public String getString(final String defaultValue) {
        if (!_node.isTextual()) {
            return defaultValue;
        }

        return _node.asText();
    }

    @Override
    public <T> T unwrap(final Class<T> type) {
        if (type == null) {
            throw new IllegalArgumentException("Type must not be null");
        }

        return type.cast(_node);
    }

    @Override
    public int size() {
        if (!_node.isArray()) {
            return 0;
        }

        return _node.size();
    }

    @Override
    public <T> T toObject(final Class<T> type, final T defaultValue) {
        if (type == null) {
            throw new IllegalArgumentException("Type must not be null");
        }

        if (_node.isNull()) {
            return null;
        }
        if (!_node.isArray() && !_node.isObject()) {
            return defaultValue;
        }
        try {
            return _mapper.convertValue(_node, type);
        } catch (final Exception e) {
            throw new JsonException(e);
        }
    }

    @Override
    public int hashCode() {
        return _node.hashCode();
    }

    @Override
    public boolean equals(final Object other) {
        if (!(other instanceof JacksonElement)) {
            return false;
        }

        final JacksonElement element = (JacksonElement) other;

        return _node.equals(element._node);
    }

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