com.vaadin.data.ContainerHelpers Maven / Gradle / Ivy
/*
* Copyright 2000-2014 Vaadin Ltd.
*
* 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.vaadin.data;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import com.vaadin.data.Container.Indexed;
/**
* Contains helper methods for containers that can be used to ease development
* of containers in Vaadin.
*
* @since 7.0
*/
public class ContainerHelpers implements Serializable {
/**
* Get a range of item ids from the container using
* {@link Indexed#getIdByIndex(int)}. This is just a helper method to aid
* developers to quickly add the required functionality to a Container
* during development. This should not be used in a "finished product"
* unless fetching an id for an index is very inexpensive because a separate
* request will be performed for each index in the range.
*
* @param startIndex
* index of the first item id to get
* @param numberOfIds
* the number of consecutive items whose ids should be returned
* @param container
* the container from which the items should be fetched
* @return A list of item ids in the range specified
*/
public static List getItemIdsUsingGetIdByIndex(int startIndex,
int numberOfIds, Container.Indexed container) {
if (container == null) {
throw new IllegalArgumentException(
"The given container cannot be null!");
}
if (startIndex < 0) {
throw new IndexOutOfBoundsException(
"Start index cannot be negative! startIndex=" + startIndex);
}
if (startIndex > container.size()) {
throw new IndexOutOfBoundsException(
"Start index exceeds container size! startIndex="
+ startIndex + " containerLastItemIndex="
+ (container.size() - 1));
}
if (numberOfIds < 1) {
if (numberOfIds == 0) {
return Collections.emptyList();
}
throw new IllegalArgumentException(
"Cannot get negative amount of items! numberOfItems="
+ numberOfIds);
}
// not included in the range
int endIndex = startIndex + numberOfIds;
if (endIndex > container.size()) {
endIndex = container.size();
}
ArrayList