Copyright Microsoft Corporation
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.
/**
 * Copyright Microsoft Corporation
 * 
 * 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.microsoft.azure.storage.core;

import java.util.Iterator;

import com.microsoft.azure.storage.OperationContext;
import com.microsoft.azure.storage.ResultSegment;
import com.microsoft.azure.storage.RetryPolicyFactory;

RESERVED FOR INTERNAL USE. Provides a lazy iterator which will retrieve the next segment of a result as the iterator
is consumed
Type parameters:
<CLIENT_TYPE> – 
           The service client type
<PARENT_TYPE> – 
           The type of the parent object, i.e. CloudBlobClient for ListContainers etc.
<ENTITY_TYPE> – 
           The type of the objects the resulting iterable objects/**
 * RESERVED FOR INTERNAL USE. Provides a lazy iterator which will retrieve the next segment of a result as the iterator
 * is consumed
 * 
 * @param <CLIENT_TYPE>
 *            The service client type
 * @param <PARENT_TYPE>
 *            The type of the parent object, i.e. CloudBlobClient for ListContainers etc.
 * @param <ENTITY_TYPE>
 *            The type of the objects the resulting iterable objects
 */
public final class LazySegmentedIterable<CLIENT_TYPE, PARENT_TYPE, ENTITY_TYPE> implements Iterable<ENTITY_TYPE> {
    
Holds the service client associated with the operations.
/**
     * Holds the service client associated with the operations.
     */
    private final CLIENT_TYPE client;

    
Holds a reference to the parent object, i.e. CloudBlobContainer for list blobs.
/**
     * Holds a reference to the parent object, i.e. CloudBlobContainer for list blobs.
     */
    private final PARENT_TYPE parentObject;

    
Holds the reference to the RetryPolicyFactory object.
/**
     * Holds the reference to the RetryPolicyFactory object.
     */
    private final RetryPolicyFactory policyFactory;

    
Holds the StorageRequest which is used to retrieve the next segment of results.
/**
     * Holds the StorageRequest which is used to retrieve the next segment of results.
     */
    private final StorageRequest<CLIENT_TYPE, PARENT_TYPE, ResultSegment<ENTITY_TYPE>> segmentGenerator;

    
Holds an object used to track the execution of the operation
/**
     * Holds an object used to track the execution of the operation
     */
    private final OperationContext opContext;

    public LazySegmentedIterable(
            final StorageRequest<CLIENT_TYPE, PARENT_TYPE, ResultSegment<ENTITY_TYPE>> segmentGenerator,
            final CLIENT_TYPE client, final PARENT_TYPE parent, final RetryPolicyFactory policyFactory,
            final OperationContext opContext) {
        this.segmentGenerator = segmentGenerator;
        this.parentObject = parent;
        this.opContext = opContext;
        this.policyFactory = policyFactory;
        this.client = client;
    }

    @Override
    public Iterator<ENTITY_TYPE> iterator() {
        return new LazySegmentedIterator<CLIENT_TYPE, PARENT_TYPE, ENTITY_TYPE>(this.segmentGenerator, this.client,
                this.parentObject, this.policyFactory, this.opContext);
    }
}