org.metawidget.inspector.json.schema.JsonSchemaInspector.java Source code

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Here is the source code for org.metawidget.inspector.json.schema.JsonSchemaInspector.java

Source

// Metawidget
//
// This file is dual licensed under both the LGPL
// (http://www.gnu.org/licenses/lgpl-2.1.html) and the EPL
// (http://www.eclipse.org/org/documents/epl-v10.php). As a
// recipient of Metawidget, you may choose to receive it under either
// the LGPL or the EPL.
//
// Commercial licenses are also available. See http://metawidget.org
// for details.

package org.metawidget.inspector.json.schema;

import static org.metawidget.inspector.InspectionResultConstants.*;

import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.metawidget.inspector.iface.InspectorException;
import org.metawidget.inspector.json.JsonInspector;
import org.metawidget.inspector.json.JsonInspectorConfig;
import org.metawidget.util.CollectionUtils;
import org.metawidget.util.XmlUtils;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

import com.google.gson.JsonElement;
import com.google.gson.JsonObject;

/**
 * Inspector to look for metadata in JSON Schema files. Consider using in conjunction with
 * <tt>JsonSchemaTypeMappingProcessorConfig</tt> to convert JSON types into Java types.
 *
 * @author <a href="http://kennardconsulting.com">Richard Kennard</a>
 */

public class JsonSchemaInspector extends JsonInspector {

    //
    // Private statics
    //

    private static final String PROPERTIES = "properties";

    //
    // Constructor
    //

    public JsonSchemaInspector(JsonInspectorConfig config) {

        super(config);
    }

    //
    // Protected methods
    //

    @Override
    public Element inspectAsDom(Object toInspect, String type, String... names) {

        JsonObject root = getRoot();

        // Traverse names (via nested properties)

        for (String name : names) {

            if (!root.has(PROPERTIES)) {
                return null;
            }

            root = root.getAsJsonObject(PROPERTIES);

            if (!root.has(name)) {
                return null;
            }

            root = root.getAsJsonObject(name);
        }

        // Start the DOM

        Document document = XmlUtils.newDocument();
        Element documentRoot = document.createElementNS(NAMESPACE, ROOT);
        documentRoot.setAttribute(VERSION, "1.0");
        document.appendChild(documentRoot);
        Element entity = document.createElementNS(NAMESPACE, ENTITY);
        entity.setAttribute(TYPE, type);
        documentRoot.appendChild(entity);

        if (names.length > 0) {
            entity.setAttribute(NAME, names[names.length - 1]);
        }

        // Write all JSON names into it as attributes

        writeJsonAttributesAsDom(entity, root);

        // Write all direct descendants

        if (root.has(PROPERTIES)) {

            root = root.getAsJsonObject(PROPERTIES);

            for (Map.Entry<String, JsonElement> entry : root.entrySet()) {

                String name = entry.getKey();
                JsonElement element = entry.getValue();

                if (!element.isJsonObject()) {
                    throw InspectorException.newException("'" + name + "' is not a " + JsonObject.class);
                }

                JsonObject property = element.getAsJsonObject();

                Element child = document.createElementNS(NAMESPACE, PROPERTY);
                child.setAttribute(NAME, name);
                writeJsonAttributesAsDom(child, property);
                entity.appendChild(child);
            }
        }

        // Return the DOM

        return documentRoot;
    }

    //
    // Private methods
    //

    private void writeJsonAttributesAsDom(Element element, JsonObject object) {

        for (Map.Entry<String, JsonElement> entry : object.entrySet()) {

            String name = entry.getKey();
            JsonElement jsonElement = entry.getValue();

            if (jsonElement.isJsonArray()) {
                List<String> array = CollectionUtils.newArrayList();
                for (Iterator<JsonElement> i = jsonElement.getAsJsonArray().iterator(); i.hasNext();) {
                    array.add(i.next().getAsString());
                }
                element.setAttribute(name, CollectionUtils.toString(array));
                continue;
            }

            if (!jsonElement.isJsonPrimitive()) {
                continue;
            }

            element.setAttribute(name, jsonElement.getAsString());
        }
    }
}