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Official Cloudant client for Java
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/*
 * Copyright (c) 2015 IBM Corp. All rights reserved.
 *
 * 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.cloudant.client.api;


import com.cloudant.client.api.model.ChangesResult;
import com.cloudant.client.api.model.ChangesResult.Row;

/**
 * Contains the Change Notifications API, supports normal and continuous feed
 * Changes.
 * 
Usage example for normal feed limiting to 10 results, with a filter:
 *  * {@code
 * // feed type normal
 * String since = db.info().getUpdateSeq(); // latest update seq
 * ChangesResult changeResult = db.changes()
 * 	.since(since)
 * 	.limit(10)
 * 	.filter("example/filter")
 * 	.getChanges();
 *
 * //process the ChangesResult
 * for (ChangesResult.Row row : changeResult.getResults()) {
 *   String docId = row.getId()
 *   JsonObject doc = row.getDoc();
 * }
 * }
 * 
 * Usage example for continuous feed, including document content:
 *  * {@code
 * // feed type continuous
 * Changes changes = db.changes()
 * 	.includeDocs(true)
 * 	.heartBeat(30000)
 * 	.continuousChanges();
 *
 * while (changes.hasNext()) {
 * 	ChangesResult.Row feed = changes.next();
 *  String docId = feed.getId();
 *  JsonObject doc = feed.getDoc();
 * }
 *
 * //while loop blocks; stop from another thread
 * changes.stop(); // stop continuous feed
 * }
 * 
 *
 * @author Ganesh K Choudhary
 * @see ChangesResult
 * @see Databases -
 * get changes
 * @since 0.0.1
 */
public class Changes {
    private com.cloudant.client.org.lightcouch.Changes changes;

    Changes(com.cloudant.client.org.lightcouch.Changes changes) {
        this.changes = changes;
    }

    /**
     * Requests Change notifications of feed type continuous.
     * Feed notifications are accessed in an iterator style.
     *
     * @return this Changes object configured for continuous feed.
     */
    public Changes continuousChanges() {
        changes = changes.continuousChanges();
        return this;
    }

    /**
     * Checks whether a feed is available in the continuous stream, blocking
     * until a feed is received.
     *
     * @return true if there is a change
     */
    public boolean hasNext() {
        return changes.hasNext();
    }

    /**
     * @return The next feed in the stream.
     */
    public Row next() {
        com.cloudant.client.org.lightcouch.ChangesResult.Row next = changes.next();
        Row row = new Row(next);
        return row;
    }

    /**
     * Stops a running continuous feed.
     */
    public void stop() {
        changes.stop();
    }

    /**
     * Requests Change notifications of feed type normal.
     *
     * @return {@link ChangesResult} encapsulating the normal feed changes
     */
    public ChangesResult getChanges() {
        com.cloudant.client.org.lightcouch.ChangesResult couchDbChangesResult = changes
                .getChanges();
        ChangesResult changeResult = new ChangesResult(couchDbChangesResult);
        return changeResult;
    }

    // Query Params

    public Changes since(String since) {
        changes = changes.since(since);
        return this;
    }


    public Changes limit(int limit) {
        changes = changes.limit(limit);
        return this;
    }


    public Changes filter(String filter) {
        changes = changes.filter(filter);
        return this;
    }


    public Changes heartBeat(long heartBeat) {
        changes = changes.heartBeat(heartBeat);
        return this;
    }


    public Changes timeout(long timeout) {
        changes = changes.timeout(timeout);
        return this;
    }


    public Changes includeDocs(boolean includeDocs) {
        changes = changes.includeDocs(includeDocs);
        return this;
    }


    public Changes style(String style) {
        changes = changes.style(style);
        return this;
    }


}