Android Open Source - NexusData Persistent Store Coordinator

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License

The source code is released under:

Apache License Version 2.0, January 2004 http://www.apache.org/licenses/ TERMS AND CONDITIONS FOR USE, REPRODUCT...

Java Source Code

package com.github.dkharrat.nexusdata.core;
//w w  w.  j a  v a  2  s.c  om
import java.net.URI;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.UUID;

import com.github.dkharrat.nexusdata.metamodel.Entity;
import com.github.dkharrat.nexusdata.metamodel.ObjectModel;
import com.github.dkharrat.nexusdata.utils.StringUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A PersistentStoreCoordinator is a mediator between a {@link ObjectContext} and other {@link PersistentStore}s.
 * It is used by an {@link ObjectContext} to obtain model information and save the object graph. From the perspective of
 * the ObjectContext, a PersistentStoreCoordinator behaves such that a group of PersistentStores appear as one virtual
 * store. This allows the ObjectContext to create the corresponding object graph from the union of the persistence
 * stores that this coordinator covers.
 */
public class PersistentStoreCoordinator {

    private static final Logger LOG = LoggerFactory.getLogger(PersistentStoreCoordinator.class);

    private final Map<UUID, PersistentStore> storeUuidToPersistentStore = new LinkedHashMap<UUID, PersistentStore>();
    private final ObjectModel model;

    /**
     * Creates a PersistentStoreCoordinator associated with the specific model.
     *
     * @param model the model that this PersistentStoreCoordinator will use
     */
    public PersistentStoreCoordinator(ObjectModel model) {
        this.model = model;
    }

    /**
     * Adds a persistent store to this coordinator. A persistent store cannot belong to multiple coordinators.
     *
     * @param store the persistent store to add
     */
    public void addStore(PersistentStore store) {
        if (store.getCoordinator() != null && store.getCoordinator() != this) {
            throw new IllegalStateException("PersistentStore " + store + " already assigned to another coordinator");
        }
        store.setPersistentStoreCoordinator(this);
        store.loadMetadata();

        if (store.getUuid() == null) {
            throw new RuntimeException("Did not get permanent UUID from store: " + store);
        }

        storeUuidToPersistentStore.put(store.getUuid(), store);

        LOG.info("Added persistent store " + store);
    }

    /**
     * Removes the specified persistent store from this coordinator.
     *
     * @param store the store to remove
     */
    public void removeStore(PersistentStore store) {
        storeUuidToPersistentStore.remove(store.getUuid());
        store.setPersistentStoreCoordinator(null);
    }

    /**
     * Returns the persistent store contained in this coordinator that is identified by the specified ID.
     *
     * @param uuid  the UUID of the persistent store to return
     *
     * @return the persistent store in this coordinator that matches the specified ID. If no such store exists,
     *         {@code null} is returned.
     */
    public PersistentStore getPersistentStore(UUID uuid) {
        return storeUuidToPersistentStore.get(uuid);
    }

    /**
     * Returns all the persistent stores contained within this coordinator.
     *
     * @return all the persistent stores contained within this coordinator
     */
    public List<PersistentStore> getPersistentStores() {
        return new ArrayList<PersistentStore>(storeUuidToPersistentStore.values());
    }

    /**
     * Returns the model associated with this coordinator.
     *
     * @return the model associated with this coordinator
     */
    public ObjectModel getModel() {
        return model;
    }

    /**
     * Returns the ObjectID from the corresponding URI representation.
     *
     * @param objectIDUri   the URI that represents the ObjectID
     *
     * @return  the ObjectID represented by the specified URI
     * @throws {@link IllegalArgumentException} if the URI represents a temporary ID or the URI is invalid
     */
    public ObjectID objectIDFromUri(URI objectIDUri) {
        if (!objectIDUri.getScheme().equals("nexusdata")) {
            throw new IllegalArgumentException("");
        } else if (StringUtil.isBlank(objectIDUri.getAuthority())) {
            throw new IllegalArgumentException("Cannot create ObjectID from temporary ID");
        }

        String[] parts = objectIDUri.getPath().split("/");
        if (parts.length < 3 || parts[1].isEmpty() || parts[2].isEmpty()) {
            throw new IllegalArgumentException("Invalid ObjectID URI format");
        }

        UUID storeUuid = UUID.fromString(objectIDUri.getAuthority());
        Entity<?> entity = model.getEntity(parts[1]);
        Object referenceObject = parts[2];
        try {
            referenceObject = Long.parseLong(parts[2]);
        } catch (NumberFormatException e) {
            // ignore; treat ref object as string
        }

        return new ObjectID(storeUuidToPersistentStore.get(storeUuid), entity, referenceObject);
    }

    //TODO: implement - must be synchronized?
    void executeFetchRequest() {

    }

    //TODO: implement - must be synchronized?
    void save(SaveChangesRequest saveRequest) {

    }
}

Java Source Code List

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