mirror of
https://github.com/berkeleydb/je.git
synced 2024-07-06 18:07:18 +00:00
252 lines
10 KiB
HTML
252 lines
10 KiB
HTML
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
|
||
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
||
<html xmlns="http://www.w3.org/1999/xhtml">
|
||
<head>
|
||
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
|
||
<title>Using Entities with Collections</title>
|
||
<link rel="stylesheet" href="gettingStarted.css" type="text/css" />
|
||
<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
|
||
<link rel="start" href="index.html" title="Berkeley DB Java Edition Collections Tutorial" />
|
||
<link rel="up" href="Entity.html" title="Chapter 4. Using Entity Classes" />
|
||
<link rel="prev" href="collectionswithentities.html" title="Creating Collections with Entity Bindings" />
|
||
<link rel="next" href="Tuple.html" title="Chapter 5. Using Tuples" />
|
||
</head>
|
||
<body>
|
||
<div xmlns="" class="navheader">
|
||
<div class="libver">
|
||
<p>Library Version 12.2.7.5</p>
|
||
</div>
|
||
<table width="100%" summary="Navigation header">
|
||
<tr>
|
||
<th colspan="3" align="center">
|
||
Using Entities with Collections
|
||
</th>
|
||
</tr>
|
||
<tr>
|
||
<td width="20%" align="left"><a accesskey="p" href="collectionswithentities.html">Prev</a> </td>
|
||
<th width="60%" align="center">Chapter 4.
|
||
Using Entity Classes
|
||
</th>
|
||
<td width="20%" align="right"> <a accesskey="n" href="Tuple.html">Next</a></td>
|
||
</tr>
|
||
</table>
|
||
<hr />
|
||
</div>
|
||
<div class="sect1" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h2 class="title" style="clear: both"><a id="entitieswithcollections"></a>
|
||
Using Entities with Collections
|
||
</h2>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
In this example entity objects, rather than key and value
|
||
objects, are used for adding and enumerating the records in a
|
||
collection. Because fewer classes and objects are involved, adding
|
||
and enumerating is done more conveniently and more simply than in
|
||
the prior examples.
|
||
</p>
|
||
<p>
|
||
For adding and iterating entities, the collection of entities
|
||
returned by
|
||
<a class="ulink" href="http://download.oracle.com/javase/1.5.0/docs/api/java/util/Map.html#values()" target="_top">Map.values</a>
|
||
|
||
is used. In general, when using an entity binding, all Java
|
||
collection methods that are passed or returned a value object will
|
||
be passed or returned an entity object instead.
|
||
</p>
|
||
<p>
|
||
The <code class="classname">Sample</code> class has been changed in this example to add
|
||
objects using the
|
||
<a class="ulink" href="http://download.oracle.com/javase/1.5.0/docs/api/java/util/Set.html#add(E)" target="_top">Set.add</a>
|
||
|
||
method rather than the
|
||
<a class="ulink" href="http://download.oracle.com/javase/1.5.0/docs/api/java/util/Map.html#put(K, V)" target="_top">Map.put</a>
|
||
|
||
method that was used in the prior examples. Entity objects are
|
||
constructed and passed to
|
||
<a class="ulink" href="http://download.oracle.com/javase/1.5.0/docs/api/java/util/Set.html#add(E)" target="_top">Set.add</a>.
|
||
</p>
|
||
<a id="entity_addsuppliers"></a>
|
||
<pre class="programlisting">import java.util.Set;
|
||
...
|
||
public class Sample
|
||
{
|
||
...
|
||
private void addSuppliers()
|
||
{
|
||
<strong class="userinput"><code> Set suppliers = views.getSupplierSet();
|
||
if (suppliers.isEmpty())
|
||
{
|
||
System.out.println("Adding Suppliers");
|
||
suppliers.add(new Supplier("S1", "Smith", 20, "London"));
|
||
suppliers.add(new Supplier("S2", "Jones", 10, "Paris"));
|
||
suppliers.add(new Supplier("S3", "Blake", 30, "Paris"));
|
||
suppliers.add(new Supplier("S4", "Clark", 20, "London"));
|
||
suppliers.add(new Supplier("S5", "Adams", 30, "Athens"));
|
||
}</code></strong>
|
||
}
|
||
|
||
private void addParts()
|
||
{
|
||
<strong class="userinput"><code> Set parts = views.getPartSet();
|
||
if (parts.isEmpty())
|
||
{
|
||
System.out.println("Adding Parts");
|
||
parts.add(new Part("P1", "Nut", "Red",
|
||
new Weight(12.0, Weight.GRAMS), "London"));
|
||
parts.add(new Part("P2", "Bolt", "Green",
|
||
new Weight(17.0, Weight.GRAMS), "Paris"));
|
||
parts.add(new Part("P3", "Screw", "Blue",
|
||
new Weight(17.0, Weight.GRAMS), "Rome"));
|
||
parts.add(new Part("P4", "Screw", "Red",
|
||
new Weight(14.0, Weight.GRAMS), "London"));
|
||
parts.add(new Part("P5", "Cam", "Blue",
|
||
new Weight(12.0, Weight.GRAMS), "Paris"));
|
||
parts.add(new Part("P6", "Cog", "Red",
|
||
new Weight(19.0, Weight.GRAMS), "London"));
|
||
}</code></strong>
|
||
}
|
||
|
||
private void addShipments()
|
||
{
|
||
<strong class="userinput"><code> Set shipments = views.getShipmentSet();
|
||
if (shipments.isEmpty())
|
||
{
|
||
System.out.println("Adding Shipments");
|
||
shipments.add(new Shipment("P1", "S1", 300));
|
||
shipments.add(new Shipment("P2", "S1", 200));
|
||
shipments.add(new Shipment("P3", "S1", 400));
|
||
shipments.add(new Shipment("P4", "S1", 200));
|
||
shipments.add(new Shipment("P5", "S1", 100));
|
||
shipments.add(new Shipment("P6", "S1", 100));
|
||
shipments.add(new Shipment("P1", "S2", 300));
|
||
shipments.add(new Shipment("P2", "S2", 400));
|
||
shipments.add(new Shipment("P2", "S3", 200));
|
||
shipments.add(new Shipment("P2", "S4", 200));
|
||
shipments.add(new Shipment("P4", "S4", 300));
|
||
shipments.add(new Shipment("P5", "S4", 400));
|
||
}</code></strong>
|
||
} </pre>
|
||
<p>
|
||
Instead of printing the key/value pairs by iterating over the
|
||
<a class="ulink" href="http://download.oracle.com/javase/1.5.0/docs/api/java/util/Map.html#entrySet()" target="_top">Map.entrySet</a>
|
||
|
||
as done in the prior example, this example
|
||
iterates over the entities in the
|
||
<a class="ulink" href="http://download.oracle.com/javase/1.5.0/docs/api/java/util/Map.html#values()" target="_top">Map.values</a>
|
||
|
||
collection.
|
||
</p>
|
||
<a id="entity_printdatabase"></a>
|
||
<pre class="programlisting">import java.util.Iterator;
|
||
import java.util.Set;
|
||
...
|
||
public class Sample
|
||
{
|
||
...
|
||
private class PrintDatabase implements TransactionWorker
|
||
{
|
||
public void doWork()
|
||
throws Exception
|
||
{
|
||
<strong class="userinput"><code> printValues("Parts",
|
||
views.getPartSet().iterator());
|
||
printValues("Suppliers",
|
||
views.getSupplierSet().iterator());</code></strong>
|
||
printValues("Suppliers for City Paris",
|
||
views.getSupplierByCityMap().duplicates(
|
||
"Paris").iterator());
|
||
<strong class="userinput"><code> printValues("Shipments",
|
||
views.getShipmentSet().iterator());</code></strong>
|
||
printValues("Shipments for Part P1",
|
||
views.getShipmentByPartMap().duplicates(
|
||
new PartKey("P1")).iterator());
|
||
printValues("Shipments for Supplier S1",
|
||
views.getShipmentBySupplierMap().duplicates(
|
||
new SupplierKey("S1")).iterator());
|
||
}
|
||
}
|
||
...
|
||
} </pre>
|
||
<p>
|
||
The output of the example program is shown below.
|
||
</p>
|
||
<pre class="programlisting">Adding Suppliers
|
||
Adding Parts
|
||
Adding Shipments
|
||
|
||
--- Parts ---
|
||
Part: number=P1 name=Nut color=Red weight=[12.0 grams] city=London
|
||
Part: number=P2 name=Bolt color=Green weight=[17.0 grams] city=Paris
|
||
Part: number=P3 name=Screw color=Blue weight=[17.0 grams] city=Rome
|
||
Part: number=P4 name=Screw color=Red weight=[14.0 grams] city=London
|
||
Part: number=P5 name=Cam color=Blue weight=[12.0 grams] city=Paris
|
||
Part: number=P6 name=Cog color=Red weight=[19.0 grams] city=London
|
||
|
||
--- Suppliers ---
|
||
Supplier: number=S1 name=Smith status=20 city=London
|
||
Supplier: number=S2 name=Jones status=10 city=Paris
|
||
Supplier: number=S3 name=Blake status=30 city=Paris
|
||
Supplier: number=S4 name=Clark status=20 city=London
|
||
Supplier: number=S5 name=Adams status=30 city=Athens
|
||
|
||
--- Suppliers for City Paris ---
|
||
Supplier: number=S2 name=Jones status=10 city=Paris
|
||
Supplier: number=S3 name=Blake status=30 city=Paris
|
||
|
||
--- Shipments ---
|
||
Shipment: part=P1 supplier=S1 quantity=300
|
||
Shipment: part=P1 supplier=S2 quantity=300
|
||
Shipment: part=P2 supplier=S1 quantity=200
|
||
Shipment: part=P2 supplier=S2 quantity=400
|
||
Shipment: part=P2 supplier=S3 quantity=200
|
||
Shipment: part=P2 supplier=S4 quantity=200
|
||
Shipment: part=P3 supplier=S1 quantity=400
|
||
Shipment: part=P4 supplier=S1 quantity=200
|
||
Shipment: part=P4 supplier=S4 quantity=300
|
||
Shipment: part=P5 supplier=S1 quantity=100
|
||
Shipment: part=P5 supplier=S4 quantity=400
|
||
Shipment: part=P6 supplier=S1 quantity=100
|
||
|
||
--- Shipments for Part P1 ---
|
||
Shipment: part=P1 supplier=S1 quantity=300
|
||
Shipment: part=P1 supplier=S2 quantity=300
|
||
|
||
--- Shipments for Supplier S1 ---
|
||
Shipment: part=P1 supplier=S1 quantity=300
|
||
Shipment: part=P2 supplier=S1 quantity=200
|
||
Shipment: part=P3 supplier=S1 quantity=400
|
||
Shipment: part=P4 supplier=S1 quantity=200
|
||
Shipment: part=P5 supplier=S1 quantity=100
|
||
Shipment: part=P6 supplier=S1 quantity=100 </pre>
|
||
</div>
|
||
<div class="navfooter">
|
||
<hr />
|
||
<table width="100%" summary="Navigation footer">
|
||
<tr>
|
||
<td width="40%" align="left"><a accesskey="p" href="collectionswithentities.html">Prev</a> </td>
|
||
<td width="20%" align="center">
|
||
<a accesskey="u" href="Entity.html">Up</a>
|
||
</td>
|
||
<td width="40%" align="right"> <a accesskey="n" href="Tuple.html">Next</a></td>
|
||
</tr>
|
||
<tr>
|
||
<td width="40%" align="left" valign="top">
|
||
Creating Collections with Entity Bindings
|
||
</td>
|
||
<td width="20%" align="center">
|
||
<a accesskey="h" href="index.html">Home</a>
|
||
</td>
|
||
<td width="40%" align="right" valign="top"> Chapter 5.
|
||
Using Tuples
|
||
</td>
|
||
</tr>
|
||
</table>
|
||
</div>
|
||
</body>
|
||
</html>
|