org.openmhealth.reference.request.SchemaRequest.java Source code

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Here is the source code for org.openmhealth.reference.request.SchemaRequest.java

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/*******************************************************************************
 * Copyright 2013 Open mHealth
 * 
 * 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 org.openmhealth.reference.request;

import java.util.Map;

import name.jenkins.paul.john.concordia.Concordia;

import org.openmhealth.reference.data.Registry;
import org.openmhealth.reference.domain.Schema;
import org.openmhealth.reference.exception.NoSuchSchemaException;
import org.openmhealth.reference.exception.OmhException;

import com.fasterxml.jackson.databind.ObjectMapper;

/**
 * <p>
 * Retrieves schemas based on the given parameters. This is analogous to the
 * registry.
 * </p>
 *
 * @author John Jenkins
 */
public class SchemaRequest extends Request<Concordia> {
    /**
     * The specific schema ID being requested.
     */
    private final String schemaId;
    /**
     * The specific schema version being requested.
     */
    private final long schemaVersion;

    /**
     * Creates a new request for a schema.
     * 
     * @param schemaId
     *        The ID for the schema that is desired.
     * 
     * @param schemaVersion
     *        The version of the schema that is desired.
     */
    public SchemaRequest(final String schemaId, final long schemaVersion) throws OmhException {

        // Validate the schema ID.
        if (schemaId == null) {
            throw new OmhException("The schema ID is missing.");
        } else {
            this.schemaId = schemaId;
        }

        // Store the schema version.
        this.schemaVersion = schemaVersion;
    }

    /*
     * (non-Javadoc)
     * @see org.openmhealth.reference.request.Request#service()
     */
    @Override
    public void service() throws OmhException {
        // First, short-circuit if this request has already been serviced.
        if (isServiced()) {
            return;
        } else {
            setServiced();
        }

        // Get the schema.
        Schema schema = Registry.getInstance().getSchema(schemaId, schemaVersion);

        // Make sure the schema exists.
        if (schema == null) {
            throw new NoSuchSchemaException(
                    "The schema with id '" + schemaId + "' and version '" + schemaVersion + "' does not exist.");
        }

        // Convert the result to a map.
        ObjectMapper mapper = new ObjectMapper();
        // We need to suppress Java's type erasure. :(
        @SuppressWarnings("unchecked")
        Map<String, Object> metaData = mapper.convertValue(schema, Map.class);

        // Remove the schema from the meta-data.
        metaData.remove(Schema.JSON_KEY_SCHEMA);

        // Save the meta-data.
        setMetaData(metaData);

        // Set the schema itself as the data.
        setData(schema.getSchema());
    }
}