www.pudn.com > cryptix-asn1-0.1.11.zip > CompoundType.java

/* $Id: CompoundType.java,v 1.5 2001/05/26 07:10:24 raif Exp $ 
 * 
 * Copyright (C) 1997-2001 The Cryptix Foundation Limited. All rights reserved. 
 * 
 * Use, modification, copying and distribution of this software is subject to 
 * the terms and conditions of the Cryptix General Licence. You should have 
 * received a copy of the Cryptix General Licence along with this library; if 
 * not, you can download a copy from http://www.cryptix.org/ 
 */ 
package cryptix.asn1.lang; 
 
import cryptix.asn1.io.ASNReader; 
import cryptix.asn1.io.ASNWriter; 
import cryptix.asn1.io.BlankElementException; 
import cryptix.asn1.io.ElementNotFoundException; 
 
import org.apache.log4j.Category; 
 
import java.io.ByteArrayInputStream; 
import java.io.ByteArrayOutputStream; 
import java.io.EOFException; 
import java.io.IOException; 
import java.io.ObjectInputStream; 
import java.io.ObjectOutputStream; 
import java.util.ArrayList; 
import java.util.Iterator; 
import java.util.ListIterator; 
 
/** 
 * The abstract implementation of an ASN.1 compound type.
 
 * 
 * This class is the superclass of SEQUENCE, SET, SEQUENCE OF and SET OF.
 
 * 
 * @version $Revision: 1.5 $ 
 * @author  Raif S. Naffah 
 */ 
public abstract class CompoundType extends Type implements IIterativeType { 
 
	// Constants and vars 
	// ....................................................................... 
 
	static Category cat = Category.getInstance(CompoundType.class.getName()); 
 
	/** 
	 * The compound type components. Each element 
	 */ 
	protected ArrayList components; 
 
	// Constructor(s) 
	// ....................................................................... 
 
	public CompoundType(String name, Tag tag) { 
		super(name, tag == null ? null : new Tag(tag.getClazz(), tag.getValue(), tag.isExplicit(), true)); 
		this.initInternal(); 
	} 
 
	// Redefinition of methods in superclass Type 
	// ....................................................................... 
 
	/** 
	 * Encodes a compound type to an output stream. 
	 * 
	 * @param os the ASN.1 stream to write to. 
	 * @exception IOException if an exception occurs during the operation. 
	 */ 
	public void encode(ASNWriter os) throws IOException { 
		String cn = this.getClass().getName(); 
		cat.debug("==> "+cn+".encode()"); 
 
      if (!this.isBlank()) 
         os.encodeStructure(this); 
      else if (this.isOptional()) // do nothing. it's cool 
         cat.warn("Skipping "+cn+" cause blank..."); 
      else 
         throw new BlankElementException(cn); 
 
		cat.debug("<== "+cn+".encode()"); 
	} 
 
	/** 
	 * Resets the elements of the current value of this instance to their 
	 * initial state. 
	 */ 
	public void reset() { 
		((ArrayList) value).clear(); 
	} 
 
	/** 
	 * Returns true if the value of this instance is not set. 
	 * 
	 * @return true if this instance's value is not set. 
	 */ 
	public boolean isBlank() { 
		return ((ArrayList) value).isEmpty(); 
	} 
 
	// IIterativeType interface implementation 
	// ....................................................................... 
 
	/** 
	 * Returns a ListIterator instance capable of iterating over this compund 
	 * type element's instance(s). 
	 * 
	 * @return a java.util.ListIterator over the instance(s) of the element of 
	 * this compound type. 
	 */ 
	public ListIterator iterator() { 
		return ((ArrayList) value).listIterator(); 
	} 
 
	/** 
	 * Returns the count of elements in the collection contained in a compound 
	 * type. 
	 * 
	 * @return the count of elements in the underlying collection of a compound 
	 * type. 
	 */ 
	public int size() { 
	   return (components == null) ? 0 : components.size(); 
	} 
 
	// other instance methods 
	// ....................................................................... 
 
	/** 
	 * Initialises the components of this instance. 
	 */ 
	protected void initInternal() { 
		components = new ArrayList(); 
		value = new ArrayList(); 
	} 
 
	/** 
	 * Returns a deep copy of this instance's components. 
	 * 
	 * @return a deep copy of this instance's components. 
	 */ 
	protected ArrayList cloneComponents() { 
		ArrayList result = null; 
		try { 
			ByteArrayOutputStream baos = new ByteArrayOutputStream(4096); 
			ObjectOutputStream oos = new ObjectOutputStream(baos); 
 
			oos.writeObject(components); 
 
			oos.flush(); 
			baos.close(); 
 
			byte[] buffer = baos.toByteArray(); 
 
			ByteArrayInputStream bais = new ByteArrayInputStream(buffer); 
			ObjectInputStream ois = new ObjectInputStream(bais); 
 
			result = (ArrayList) ois.readObject(); 
 
			bais.close(); 
			buffer = null; 
		} catch (IOException x) { 
			cat.error("Got an IOException ("+x.getMessage()+") while cloning this instance's components. Returning null..."); 
		} catch (ClassNotFoundException x) { 
			cat.error("Got a ClassNotFoundException ("+x.getMessage()+") while cloning this instance's components. Returning null..."); 
		} 
 
		return result; 
	} 
 
   /** 
    * Returns true if the designated value is equal to the value of 
    * this instance.
 
    * 
    * @param obj a value to compare with the value of this instance. 
    * @return true if this instance has an equal, non-null value to 
    * the designated one; false otherwise. 
    */ 
   protected boolean sameValue(Object obj) { 
      if (obj == null) 
         return false; 
 
      if (!(obj instanceof ArrayList)) 
         return false; 
 
      if (((ArrayList) obj).size() != this.size()) 
         return false; 
 
		Iterator src = ((ArrayList) obj).iterator(); 
		Iterator dst = this.iterator(); 
		IType ts; 
		IType td; 
		while (src.hasNext() && dst.hasNext()) { 
			ts = (IType) src.next(); 
			td = (IType) dst.next(); 
			if (!ts.equals(td)) 
			   return false; 
		} 
 
      return true; 
   } 
}