eclipse collections入门

摘要：配合一下方法使用类似的方法，用于提取一个里头的一个属性出来。当然，也可以简写为主要用来过滤集合。配合使用功能与相同，只是把该筛选条件内置在中然后这里直接使用，传入参数与功能相反集合分区只取出一个符合条件的计数与条件满足判断其他转参考

配合一下方法使用：

collect

flatCollect

groupBy

minBy

maxBy

toSortedListBy

sortThisBy

toMap

类似guava的transform方法，用于提取一个object里头的一个属性出来。

Function nameFunction = Customer::getName;
MutableList customerNames = customers.collect(nameFunction);

当然，也可以简写为

MutableList customerNames = customers.collect(Customer::getName);

MutableList allOrderedLineItems = company.getOrders().flatCollect(Order::getLineItems);

MutableSet actualItemNames = allOrderedLineItems.collect(LineItem::getName).toSet();

主要用来过滤集合。配合使用：

select

reject

detect

count

anySatisfy

allSatisfy

MutableList customersFromLondon = customers.select(c -> "London".equals(c.getCity()));

功能与select相同，只是把该筛选条件内置在domain中
Customer:

public boolean livesIn(String city){
        return this.city.equals(city);
}

然后这里直接使用，传入参数：

MutableList customersFromLondon = customers.selectWith(Customer::livesIn,"London");

与selectWith功能相反

MutableList customersNotFromLondon = company.getCustomers().rejectWith(Customer::livesIn, "London");

PartitionMutableList partitionedList = this.company.getCustomers().partitionWith(Customer::livesIn, "London");
        MutableList customersFromLondon = partitionedList.getSelected();
        MutableList customersNotFromLondon = partitionedList.getRejected();

public Customer getCustomerNamed(String name) {
        return customers.detect(c -> name.equals(c.getName()));
    }

int numberOfCustomerFromLondon = company.getCustomers().countWith(Customer::livesIn,"London");

MutableList sortedTotalValues = company.getCustomers().collect(Customer::getTotalOrderValue).sortThis();
Assert.assertEquals("Highest total order value", Double.valueOf(857.0), sortedTotalValues.getLast());
Assert.assertEquals("Lowest total order value", Double.valueOf(71.0), sortedTotalValues.getFirst());

Double maximumTotalOrderValue = company.getCustomers().collect(Customer::getTotalOrderValue).max();
Customer customerWithMaxTotalOrderValue = company.getCustomers().maxBy(Customer::getTotalOrderValue);

Predicate CUSTOMER_FROM_LONDON = customer -> customer.getCity().equals("London");
boolean anyCustomersFromLondon = company.getCustomers().anySatisfy(CUSTOMER_FROM_LONDON);
boolean allCustomersFromLondon = company.getCustomers().allSatisfy(CUSTOMER_FROM_LONDON);

MutableBag bag    = HashBag.newBagWith("one","two","two","three","three","three");    
Assert.assertEquals(3,bag.occurrencesOf("three"));    
bag.add("one");    
Assert.assertEquals(2,bag.occurrencesOf("one"));

MutableMap petTypeCounts = UnifiedMap.newMap();

MutableList转MutableSet

MutableList allOrderedLineItems = company.getOrders().flatCollect(Order::getLineItems);
MutableSet actualItemNames = allOrderedLineItems.collect(LineItem::getName).toSet();

UnifiedSet.newSetWith

MutableSet people = UnifiedSet.newSetWith(mrSmith,mrsSmith,mrJones);    
int numAddresses = people.collect(addressFunction).size();    
System.out.println(numAddresses);

MutableListMultimap multimap = company.getCustomers().groupBy(Customer::getCity);
Assert.assertEquals(FastList.newListWith(this.company.getCustomerNamed("Mary")),multimap.get("Liphook"));
MutableList Liphooks = multimap.get("Liphook");

public boolean hasSupply(String itemName){
    return ArrayIterate.contains(itemNames,itemName);
}

List orders = this.company.getMostRecentCustomer().getOrders();
MutableList orderValues = ListIterate.collect(orders, Order::getValue);

String tildeSeparatedNames = company.getSuppliers().collect(Supplier::getName).makeString("~");

eclipse-collections-kata