ch.agent.crnickl.mongodb.ReadMethodsForProperty.java Source code

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Here is the source code for ch.agent.crnickl.mongodb.ReadMethodsForProperty.java

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/*
 *   Copyright 2012-2013 Hauser Olsson 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 ch.agent.crnickl.mongodb;

import java.util.ArrayList;
import java.util.Collection;
import java.util.regex.Pattern;

import org.bson.types.ObjectId;

import ch.agent.crnickl.T2DBException;
import ch.agent.crnickl.T2DBMsg;
import ch.agent.crnickl.T2DBMsg.E;
import ch.agent.crnickl.api.DBObjectType;
import ch.agent.crnickl.api.Database;
import ch.agent.crnickl.api.Property;
import ch.agent.crnickl.api.Surrogate;
import ch.agent.crnickl.api.ValueType;
import ch.agent.crnickl.impl.PropertyImpl;
import ch.agent.crnickl.mongodb.T2DBMMsg.J;

import com.mongodb.BasicDBObject;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;

/**
 * A stateless object with methods providing read access to properties.
 *  
 * @author Jean-Paul Vetterli
 */
public class ReadMethodsForProperty extends MongoDatabaseMethods {

    public ReadMethodsForProperty() {
    }

    /**
     * Find a property by its name in a database.
     * 
     * @param database a database 
     * @param name a string 
     * @return a property or null
     * @throws T2DBException
     */
    public <T> Property<T> getProperty(Database database, String name) throws T2DBException {
        try {
            DBCollection coll = getMongoDB(database).getProperties();
            DBObject obj = coll.findOne(mongoObject(MongoDatabase.FLD_PROP_NAME, name));
            if (obj != null)
                return unpack(database, (BasicDBObject) obj);
            else
                return null;
        } catch (Exception e) {
            throw T2DBMsg.exception(e, E.E20104, name);
        }
    }

    /**
     * Find a collection of properties with names matching a pattern.
     * If the pattern is enclosed in slashes it is taken as a standard
     * regexp pattern; the slashes will be removed. If it is not enclosed
     * in slashes, it is taken as a minimal pattern and all occurrences of
     * "*" will be replaced with ".*" (zero or more arbitrary characters). 
     * 
     * @param database a database
     * @param pattern a simple pattern or a regexp pattern
     * @return a collection of properties, possibly empty, never null
     * @throws T2DBException
     */
    public Collection<Property<?>> getProperties(Database database, String pattern) throws T2DBException {
        try {
            DBCollection coll = getMongoDB(database).getProperties();
            DBObject query = null;
            if (pattern != null && pattern.length() > 0) {
                String regexp = extractRegexp(pattern);
                if (regexp == null)
                    pattern = pattern.replace("*", ".*");
                else
                    pattern = regexp;
                query = mongoObject(MongoDatabase.FLD_PROP_NAME, Pattern.compile(pattern));
            }
            DBCursor cursor = coll.find(query);
            Collection<Property<?>> result = new ArrayList<Property<?>>();
            try {
                while (cursor.hasNext()) {
                    result.add(unpack(database, (BasicDBObject) cursor.next()));
                }
            } finally {
                cursor.close();
            }
            return result;
        } catch (Exception e) {
            throw T2DBMsg.exception(e, E.E20106, pattern);
        }
    }

    /**
     * Find a property corresponding to a surrogate.
     * 
     * @param s a surrogate
     * @return a property or null
     * @throws T2DBException
     */
    public <T> Property<T> getProperty(Surrogate s) throws T2DBException {
        try {
            DBObject obj = getObject(s, false);
            if (obj != null)
                return unpack(s.getDatabase(), (BasicDBObject) obj);
            else
                return null;
        } catch (Exception e) {
            throw T2DBMsg.exception(e, E.E20105, s.toString());
        }
    }

    private <T> Property<T> unpack(Database db, BasicDBObject obj) throws T2DBException {
        try {
            ObjectId id = obj.getObjectId(MongoDatabase.FLD_ID);
            String name = obj.getString(MongoDatabase.FLD_PROP_NAME);
            ObjectId vtId = obj.getObjectId(MongoDatabase.FLD_PROP_VT);
            Boolean indexed = obj.getBoolean(MongoDatabase.FLD_PROP_INDEXED);
            Surrogate vts = makeSurrogate(db, DBObjectType.VALUE_TYPE, new MongoDBObjectId(vtId));
            ValueType<T> vt = db.getValueType(vts);
            Surrogate s = makeSurrogate(db, DBObjectType.PROPERTY, new MongoDBObjectId(id));
            checkIntegrity(vt, vts, s);
            return new PropertyImpl<T>(name, vt, indexed, s);
        } catch (ClassCastException e) {
            throw T2DBMMsg.exception(e, J.J81010, obj.toString());
        }
    }

}