Java tutorial
package org.bouncycastle.asn1; import java.io.IOException; import java.io.OutputStream; /** * Base class for ASN.1 primitive objects. These are the actual objects used to generate byte encodings. */ public abstract class ASN1Primitive extends ASN1Object { ASN1Primitive() { } public void encodeTo(OutputStream output) throws IOException { ASN1OutputStream.create(output).writeObject(this); } public void encodeTo(OutputStream output, String encoding) throws IOException { ASN1OutputStream.create(output, encoding).writeObject(this); } /** * Create a base ASN.1 object from a byte stream. * * @param data the byte stream to parse. * @return the base ASN.1 object represented by the byte stream. * @exception IOException if there is a problem parsing the data, or parsing the stream did not exhaust the available data. */ public static ASN1Primitive fromByteArray(byte[] data) throws IOException { ASN1InputStream aIn = new ASN1InputStream(data); try { ASN1Primitive o = aIn.readObject(); if (aIn.available() != 0) { throw new IOException("Extra data detected in stream"); } return o; } catch (ClassCastException e) { throw new IOException("cannot recognise object in stream"); } } public final boolean equals(Object o) { if (this == o) { return true; } return (o instanceof ASN1Encodable) && asn1Equals(((ASN1Encodable) o).toASN1Primitive()); } public final boolean equals(ASN1Encodable other) { return this == other || (null != other && asn1Equals(other.toASN1Primitive())); } public final boolean equals(ASN1Primitive other) { return this == other || asn1Equals(other); } public final ASN1Primitive toASN1Primitive() { return this; } /** * Return the current object as one which encodes using Distinguished Encoding Rules. * * @return a DER version of this. */ ASN1Primitive toDERObject() { return this; } /** * Return the current object as one which encodes using Definite Length encoding. * * @return a DL version of this. */ ASN1Primitive toDLObject() { return this; } public abstract int hashCode(); /** * Return true if this objected is a CONSTRUCTED one, false otherwise. * @return true if CONSTRUCTED bit set on object's tag, false otherwise. */ abstract boolean isConstructed(); /** * Return the length of the encoding this object will produce. * @return the length of the object's encoding. * @throws IOException if the encoding length cannot be calculated. */ abstract int encodedLength() throws IOException; abstract void encode(ASN1OutputStream out, boolean withTag) throws IOException; /** * Equality (similarity) comparison for two ASN1Primitive objects. */ abstract boolean asn1Equals(ASN1Primitive o); }