Examples of ASN1Choice

codec.asn1.ASN1Choice
This type represents the ASN.1 CHOICE type as specified in ITU-T Recommendation X.680. On decoding, the decoder must be able to decide umambiguously which alternative choice it has to decode. For this reason all elements in a CHOICE type must have distinctive tags.
This class does not enforce the distinctive tag rule. Instead, the alternative with the first matching tag should be chosen by decoders. The application that builds the CHOICE type must take care not to produce ambiguous sets of alternatives.
This class distinguishes alternative choices and an inner type. Upon decoding, the inner type is selected from the list of choices based on the identifier octets encountered in the encoded stream. This type is then {@link #setInnerType set as the inner type} of thisinstance. Unless an inner type is set (either explicitly or by means of decoding) the state of the choice is undefined.
This instance always mimicks its inner type. The methods {@link ASN1Type#getTag getTag}, {@link ASN1Type#getTagClass getTagClass}, {@link ASN1Type#getValue getValue} all returnthe appropriate results of the corresponding method of the inner type. On encoding an instance of this class the inner type is encoded.
No nested CHOICE classes are supported. In principle this is easily supported but it is not good style to build such structures. @author Volker Roth @author Stefan Endler @version "$Id: ASN1Choice.java,v 1.3 2007/08/11 18:21:50 sendler Exp $"
org.apache.harmony.security.asn1.ASN1Choice
etf.org/rfc/rfc3280.txt) Time ::= CHOICE { utcTime UTCTime, generalTime GeneralizedTime } Validity ::= SEQUENCE { notBefore Time, notAfter Time } 1)First approach: No application class to represent ASN.1 Time notation The Time notation is a choice of different time formats: UTC and Generalized. Both of them are mapped to java.util.Date object, so an application class that represents ASN.1 Validity notation may keep values as Date objects. So a custom ASN.1 Time choice type should map its notation to Date object. class Time { // custom ASN.1 choice class: maps Time to is notation public static final ASN1Choice asn1 = new ASN1Choice(new ASN1Type[] { ASN1GeneralizedTime.asn1, ASN1UTCTime.asn1 }) { public int getIndex(java.lang.Object object) { return 0; // always encode as ASN1GeneralizedTime } public Object getObjectToEncode(Object object) { // A value to be encoded value is a Date object // pass it to custom time class return object; } }; } class Validity { private Date notBefore; // choice as Date private Date notAfter; // choice as Date ... // constructors and other methods go here // custom ASN.1 sequence class: maps Validity class to is notation public static final ASN1Sequence ASN1 = new ASN1Sequence(new ASN1Type[] {Time.asn1, Time.asn1 }) { protected Object getObject(Object[] values) { // ASN.1 Time choice passed Data object - use it return new Validity((Date) values[0], (Date) values[1]); } protected void getValues(Object object, Object[] values) { Validity validity = (Validity) object; // pass Date objects to ASN.1 Time choice values[0] = validity.notBefore; values[1] = validity.notAfter; } } } 2)Second approach: There is an application class to represent ASN.1 Time notation If it is a matter what time format should be used to decode/encode Date objects a class to represent ASN.1 Time notation must be created. For example, class Time { private Date utcTime; private Date gTime; ... // constructors and other methods go here // custom ASN.1 choice class: maps Time to is notation public static final ASN1Choice asn1 = new ASN1Choice(new ASN1Type[] { ASN1GeneralizedTime.asn1, ASN1UTCTime.asn1 }) { public Object getDecodedObject(BerInputStream in) { // create Time object to pass as decoded value Time time = new Time(); if (in.choiceIndex==0) { // we decoded GeneralizedTime // store decoded Date value in corresponding field time.gTime = in.content; // return it return time; } else { // we decoded UTCTime // store decoded Date value in corresponding field time.utcTime = in.content; // return it return time; } } public int getIndex(java.lang.Object object) { Time time = (Time)object; if(time.utcTime!=null){ // encode Date as UTCTime return 1; } else { // otherwise encode Date as GeneralizedTime return 0; } } public Object getObjectToEncode(Object object) { Time time = (Time)object; if(time.utcTime!=null){ // encode Date as UTCTime return 1; } else { // otherwise encode Date as GeneralizedTime return 0; } } }; } So now Validity class must keep all values in Time object and its custom ASN.1 sequence class must handle this class of objects class Validity { private Time notBefore; // now it is a Time!!! private Time notAfter; // now it is a Time!!! ... // constructors and other methods go here // custom ASN.1 sequence class: maps Validity class to is notation public static final ASN1Sequence ASN1 = new ASN1Sequence(new ASN1Type[] {Time.asn1, Time.asn1 }) { protected Object getObject(Object[] values) { // We've gotten Time objects here !!! return new Validity((Time) values[0], (Time) values[1]); } protected void getValues(Object object, Object[] values) { Validity validity = (Validity) object; // pass Time objects to ASN.1 Time choice values[0] = validity.notBefore; values[1] = validity.notAfter; } } } @see http://asn1.elibel.tm.fr/en/standards/index.htm

Examples of org.apache.harmony.security.asn1.ASN1Choice

    /**
     * TODO Put method description here
     */
    public void testChoiceOfChoice() throws Exception {


        ASN1Choice choice1 = new ASN1Choice(new ASN1Type[] {
                ASN1Oid.getInstance(), // first
                ASN1Boolean.getInstance(),// second: decoded component
                ASN1Integer.getInstance() // third
                }) {


            public Object getDecodedObject(BerInputStream in)
                    throws IOException {


                assertEquals("choice1", 1, in.choiceIndex);


                return in.content;
            }


            public Object getObjectToEncode(Object obj) {
                return obj;
            }


            public int getIndex(Object obj) {
                return 0;
            }
        };


        ASN1Choice choice2 = new ASN1Choice(new ASN1Type[] { choice1, // first: decoded component
                ASN1BitString.getInstance() // second
                }) {


            public Object getDecodedObject(BerInputStream in)
                    throws IOException {


                assertEquals("choice2", 0, in.choiceIndex);


                return in.content;
            }


            public Object getObjectToEncode(Object obj) {
                return obj;
            }


            public int getIndex(Object obj) {
                return 0;
            }
        };


        Boolean b = (Boolean) choice2.decode(new byte[] { 0x01, 0x01, 0x00 });


        assertTrue(b == Boolean.FALSE);
    }

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Examples of org.apache.harmony.security.asn1.ASN1Choice

    /**
     * TODO Put method description here
     */
    public void testDistinctTags() throws Exception {


        ASN1Choice choice1 = new ASN1Choice(new ASN1Type[] {
                ASN1Boolean.getInstance(),// component to be checked
                ASN1Oid.getInstance(), ASN1Integer.getInstance() }) {


            public Object getObjectToEncode(Object obj) {
                return obj;
            }


            public int getIndex(Object obj) {
                return 0;
            }
        };


        // two ASN.1 booleans
        try {
            new ASN1Choice(new ASN1Type[] { choice1, //
                    ASN1Boolean.getInstance() // component to be checked
                    }) {


                public Object getObjectToEncode(Object obj) {
                    return obj;
                }


                public int getIndex(Object obj) {
                    return 0;
                }
            };
            fail("No expected IllegalArgumentException");
        } catch (IllegalArgumentException e) {
        }


        // ASN.1 ANY
        try {
            new ASN1Choice(new ASN1Type[] { choice1,//
                    ASN1Any.getInstance() // component to be checked
                    }) {


                public Object getObjectToEncode(Object obj) {
                    return obj;
                }


                public int getIndex(Object obj) {
                    return 0;
                }
            };
            fail("No expected IllegalArgumentException");
        } catch (IllegalArgumentException e) {
        }


        // two choices
        ASN1Choice choice2 = new ASN1Choice(new ASN1Type[] {
                ASN1BitString.getInstance(), //
                ASN1Boolean.getInstance() //component to be checked
                }) {


            public Object getObjectToEncode(Object obj) {
                return obj;
            }


            public int getIndex(Object obj) {
                return 0;
            }
        };


        try {
            new ASN1Choice(new ASN1Type[] { choice1, choice2 }) {


                public Object getObjectToEncode(Object obj) {
                    return obj;
                }

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