设计模式-结构型模式-组合

结构型模式:结构型对象模式不是对接口或实现进行组合的.而是描述了如何对一些对象进行组合,从而实现新功能的一些方法.

compiste:将对象组合成树形结构以表示,"部份-整体"的层次结构.使用的单个对象和组合对象使用具有一致性.

package structure.compiste;

/**
* A Component with some common function implementation
* You can abstract it.
*/
import java.util.*;

public class Employee {

String name;
float salary;
Vector subordinates;
boolean isLeaf;
Employee parent = null;

//-------------------------------------------
public Employee(String _name, float _salary) {
name = _name;
salary = _salary;
subordinates = new Vector();
isLeaf = false;
}

//-------------------------------------------
public Employee(Employee _parent, String _name, float _salary) {
name = _name;
salary = _salary;
parent = _parent;
subordinates = new Vector();
isLeaf = false;
}

//-------------------------------------------
public void setLeaf(boolean b) {
isLeaf = b; //if true, do not allow children
}

//-------------------------------------------
public float getSalary() {
return salary;
}

//-------------------------------------------
public String getName() {
return name;
}

//-------------------------------------------
public boolean add(Employee e) {
if (!isLeaf) {
subordinates.addElement(e);
}
return isLeaf; //false if unsuccessful
}

//-------------------------------------------
public void remove(Employee e) {
if (!isLeaf) {
subordinates.removeElement(e);
}
}

//-------------------------------------------
public Enumeration elements() {
return subordinates.elements();
}

//-------------------------------------------
public Employee getChild(String s) {
Employee newEmp = null;

if (getName().equals(s)) {
return this;
}
else {
boolean found = false;
Enumeration e = elements();
while (e.hasMoreElements() && (!found)) {
newEmp = (Employee) e.nextElement();
found = newEmp.getName().equals(s);
if (!found) {
newEmp = newEmp.getChild(s);
found = (newEmp != null);
}
}
if (found) {
return newEmp;
}
else {
return null;
}
}
}

//-------------------------------------------
public float getSalaries() {
float sum = salary;
for (int i = 0; i < subordinates.size(); i++) {
sum += ((Employee) subordinates.elementAt(i)).getSalaries();
}
return sum;
}

}

package structure.compiste;

import java.awt.*;
import java.awt.event.*;
import java.util.*;

// swing classes
import javax.swing.text.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.border.*;
import javax.swing.tree.*;

public class empTree extends JxFrame implements TreeSelectionListener {

Employee boss, marketVP, prodVP;
Employee salesMgr, advMgr;
Employee prodMgr, shipMgr;

JScrollPane sp;
JPanel treePanel;
JTree tree;
DefaultMutableTreeNode troot;
JLabel cost;

public empTree() {
super("Employee tree");
makeEmployees();
setGUI();
}

//--------------------------------------
private void setGUI() {
treePanel = new JPanel();
getContentPane().add(treePanel);
treePanel.setLayout(new BorderLayout());

sp = new JScrollPane();
treePanel.add("Center", sp);
treePanel.add("South", cost = new JLabel(" "));

treePanel.setBorder(new BevelBorder(BevelBorder.RAISED));
troot = new DefaultMutableTreeNode(boss.getName());
tree = new JTree(troot);
tree.setBackground(Color.lightGray);
loadTree(boss);
/* Put the Tree in a scroller. */

sp.getViewport().add(tree);
setSize(new Dimension(200, 300));
setVisible(true);

}

//------------------------------------
public void loadTree(Employee topDog) {
DefaultMutableTreeNode troot;
troot = new DefaultMutableTreeNode(topDog.getName());
treePanel.remove(tree);
tree = new JTree(troot);
tree.addTreeSelectionListener(this);
sp.getViewport().add(tree);

addNodes(troot, topDog);
tree.expandRow(0);
repaint();
}

//--------------------------------------
private void addNodes(DefaultMutableTreeNode pnode, Employee emp) {
DefaultMutableTreeNode node;

Enumeration e = emp.elements();
while (e.hasMoreElements()) {
Employee newEmp = (Employee) e.nextElement();
node = new DefaultMutableTreeNode(newEmp.getName());
pnode.add(node);
addNodes(node, newEmp);
}
}

//--------------------------------------
private void makeEmployees() {
boss = new Employee("CEO", 200000);
boss.add(marketVP = new Employee("Marketing VP", 100000));
boss.add(prodVP = new Employee("Production VP", 100000));

marketVP.add(salesMgr = new Employee("Sales Mgr", 50000));
marketVP.add(advMgr = new Employee("Advt Mgr", 50000));

for (int i = 0; i < 5; i++)
salesMgr.add(new Employee("Sales " + new Integer(i).toString(), 30000.0F + (float) (Math.random() - 0.5) * 10000));
advMgr.add(new Employee("Secy", 20000));

prodVP.add(prodMgr = new Employee("Prod Mgr", 40000));
prodVP.add(shipMgr = new Employee("Ship Mgr", 35000));
for (int i = 0; i < 4; i++)
prodMgr.add(new Employee("Manuf " + new Integer(i).toString(), 25000.0F + (float) (Math.random() - 0.5) * 5000));
for (int i = 0; i < 3; i++)
shipMgr.add(new Employee("ShipClrk " + new Integer(i).toString(), 20000.0F + (float) (Math.random() - 0.5) * 5000));

}

//--------------------------------------
public void valueChanged(TreeSelectionEvent evt) {
TreePath path = evt.getPath();
String selectedTerm = path.getLastPathComponent().toString();

Employee emp = boss.getChild(selectedTerm);
if (emp != null)
cost.setText(new Float(emp.getSalaries()).toString());
}

//--------------------------------------
static public void main(String argv[]) {
new empTree();
}
}

package structure.compiste;

import java.awt.*;
import java.awt.event.*;
import java.util.*;

// swing classes
import javax.swing.text.*;
import javax.swing.*;
import javax.swing.event.*;

public class JxFrame extends JFrame {

public JxFrame(String title) {
super(title);
setCloseClick();
setLF();
}

private void setCloseClick() {
//create window listener to respond to window close click
addWindowListener(new WindowAdapter() {

public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
}

//------------------------------------------
private void setLF() {
// Force SwingApp to come up in the System L&F
String laf = UIManager.getSystemLookAndFeelClassName();
try {
UIManager.setLookAndFeel(laf);
}
catch (UnsupportedLookAndFeelException exc) {
System.err.println("Warning: UnsupportedLookAndFeel: " + laf);
}
catch (Exception exc) {
System.err.println("Error loading " + laf + ": " + exc);
}
}
}