com.mongodb.DBCollectionProxyFactory.java Source code

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Here is the source code for com.mongodb.DBCollectionProxyFactory.java

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/*******************************************************************************
 * Copyright 2015, The IKANOW Open Source Project.
 *
 * 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 com.mongodb;

import java.lang.reflect.Method;

import org.springframework.cglib.proxy.Enhancer;
import org.springframework.cglib.proxy.MethodInterceptor;
import org.springframework.cglib.proxy.MethodProxy;

/** Defensive extension to DBCollection, doesn't error out whenever a node goes down or master/slave assignments chage 
 * (but can block for a while)
 *  THIS CLASS HAS NO COVERAGE SO NEED TO HANDLE TEST ON MODIFICATION
 * @author acp
 */
public class DBCollectionProxyFactory {

    /** Get the enhanced DB collection from the provided one 
     * @param dbc - the collection to enhance
     * @return - the enhanced collection
     */
    public static DBCollection get(final DBCollection dbc) {
        return get(dbc, false);
    }

    /** Get the enhanced DB collection from the provided one 
     * @param dbc - the collection to enhance
     * @return - the enhanced collection
     */
    public static DBCollection get(final DBCollection dbc, final boolean is_mock) {
        return get(dbc.getDB(), dbc.getName(), is_mock);
    }

    /** Get the enhanced DB collection from the provided one 
     * @param db db name
     * @param name collection name
     * @return the enhanced collection
     */
    @SuppressWarnings("deprecation")
    public static DBCollection get(final DB db, final String name, final boolean is_mock) {

        Enhancer collectionEnhancer = new Enhancer();
        collectionEnhancer
                .setSuperclass(is_mock ? com.mongodb.FongoDBCollection.class : com.mongodb.DBCollectionImpl.class);
        MethodInterceptor collectionMi = new MethodInterceptor() {
            boolean _top_level = true;

            @Override
            public Object intercept(final Object object, final Method method, final Object[] args,
                    final MethodProxy methodProxy) throws Throwable {
                if (_top_level) {
                    try {
                        _top_level = false;
                        for (int count = 0;; count++) {
                            //DEBUG
                            //System.out.println("intercepted method: " + method.toString() + ", loop=" + count + ");

                            try {
                                Object o = methodProxy.invokeSuper(object, args);

                                if (o instanceof DBCursor) {
                                    o = getCursor((DBCursor) o);
                                }
                                return o;
                            } catch (com.mongodb.MongoException e) {
                                if (count < 60) {
                                    continue;
                                }
                                throw e;
                            }
                        }
                    } finally {
                        _top_level = true;
                    }
                } else {
                    return methodProxy.invokeSuper(object, args);
                }
            }

        };
        collectionEnhancer.setCallback(collectionMi);
        return (DBCollection) collectionEnhancer
                .create(is_mock ? new Class[] { com.mongodb.FongoDB.class, String.class }
                        : new Class[] { com.mongodb.DBApiLayer.class, String.class }, new Object[] { db, name });
    }

    ///////////////////////////////////////////////////////////////////////////

    //DO THE SAME FOR DBCURSOR

    protected static DBCursor getCursor(final DBCursor from) {
        Enhancer dbcursorEnhancer = new Enhancer();
        dbcursorEnhancer.setSuperclass(com.mongodb.DBCursor.class);

        MethodInterceptor collectionMi = new MethodInterceptor() {
            boolean _top_level = true;

            @Override
            public Object intercept(Object object, Method method, Object[] args, MethodProxy methodProxy)
                    throws Throwable {
                if (_top_level) {
                    try {
                        _top_level = false;
                        for (int count = 0;; count++) {
                            //DEBUG
                            //System.out.println("intercepted method: " + method.toString() + ", loop=" + count + ");

                            try {
                                Object o = methodProxy.invokeSuper(object, args);
                                return o;
                            } catch (com.mongodb.MongoException e) {
                                if (count < 60) {
                                    continue;
                                }
                                throw e;
                            }
                        }
                    } finally {
                        _top_level = true;
                    }
                } else {
                    return methodProxy.invokeSuper(object, args);
                }
            }
        };
        dbcursorEnhancer.setCallback(collectionMi);
        return (DBCursor) dbcursorEnhancer.create(
                new Class[] { DBCollection.class, DBObject.class, DBObject.class, ReadPreference.class },
                new Object[] { from.getCollection(), from.getQuery(), from.getKeysWanted(),
                        from.getReadPreference() });
    }
}