Mega Code Archive
Composite Patterns in Java 2
<![CDATA[
/*
Software Architecture Design Patterns in Java
by Partha Kuchana
Auerbach Publications
*/
import java.util.Enumeration;
import java.util.Vector;
public class CompositeDemo {
public static final String SEPARATOR = ", ";
public static void main(String[] args) {
FileSystemComponent mainFolder = new DirComponent("Year2000");
FileSystemComponent subFolder1 = new DirComponent("Jan");
FileSystemComponent subFolder2 = new DirComponent("Feb");
FileSystemComponent folder1File1 = new FileComponent(
"Jan1DataFile.txt", 1000);
FileSystemComponent folder1File2 = new FileComponent(
"Jan2DataFile.txt", 2000);
FileSystemComponent folder2File1 = new FileComponent(
"Feb1DataFile.txt", 3000);
FileSystemComponent folder2File2 = new FileComponent(
"Feb2DataFile.txt", 4000);
try {
mainFolder.addComponent(subFolder1);
mainFolder.addComponent(subFolder2);
subFolder1.addComponent(folder1File1);
subFolder1.addComponent(folder1File2);
subFolder2.addComponent(folder2File1);
subFolder2.addComponent(folder2File2);
} catch (CompositeException ex) {
//
}
//Client refers to both composite &
//individual components in a uniform manner
System.out.println(" Main Folder Size= "
+ mainFolder.getComponentSize() + "kb");
System.out.println(" Sub Folder1 Size= "
+ subFolder1.getComponentSize() + "kb");
System.out.println(" File1 in Folder1 size= "
+ folder1File1.getComponentSize() + "kb");
}
}
class FileComponent extends FileSystemComponent {
private long size;
public FileComponent(String cName, long sz) {
super(cName);
size = sz;
}
public long getComponentSize() {
return size;
}
} // End of class
abstract class FileSystemComponent {
String name;
public FileSystemComponent(String cName) {
name = cName;
}
public void addComponent(FileSystemComponent component)
throws CompositeException {
throw new CompositeException("Invalid Operation. Not Supported");
}
public FileSystemComponent getComponent(int componentNum)
throws CompositeException {
throw new CompositeException("Invalid Operation. Not Supported");
}
public abstract long getComponentSize();
} // End of class FileSystemComponent
class CompositeException extends Exception {
public CompositeException(String msg) {
super(msg);
}
} // End of class
class DirComponent extends FileSystemComponent {
Vector dirContents = new Vector();
//individual files/sub folders collection
public DirComponent(String cName) {
super(cName);
}
public void addComponent(FileSystemComponent fc) throws CompositeException {
dirContents.add(fc);
}
public FileSystemComponent getComponent(int location)
throws CompositeException {
return (FileSystemComponent) dirContents.elementAt(location);
}
public long getComponentSize() {
long sizeOfAllFiles = 0;
Enumeration e = dirContents.elements();
while (e.hasMoreElements()) {
FileSystemComponent component = (FileSystemComponent) e
.nextElement();
sizeOfAllFiles = sizeOfAllFiles + (component.getComponentSize());
}
return sizeOfAllFiles;
}
} // End of class
]]>