001/**
002The contents of this file are subject to the Mozilla Public License Version 1.1 
003(the "License"); you may not use this file except in compliance with the License. 
004You may obtain a copy of the License at http://www.mozilla.org/MPL/ 
005Software distributed under the License is distributed on an "AS IS" basis, 
006WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the 
007specific language governing rights and limitations under the License. 
008
009The Original Code is "Segment.java".  Description: 
010"Represents an HL7 message segment, which is a unit of data that contains multiple fields.
011@author Bryan Tripp (bryan_tripp@sourceforge.net)" 
012
013The Initial Developer of the Original Code is University Health Network. Copyright (C) 
0142001.  All Rights Reserved. 
015
016Contributor(s): ______________________________________. 
017
018Alternatively, the contents of this file may be used under the terms of the 
019GNU General Public License (the  �GPL�), in which case the provisions of the GPL are 
020applicable instead of those above.  If you wish to allow use of your version of this 
021file only under the terms of the GPL and not to allow others to use your version 
022of this file under the MPL, indicate your decision by deleting  the provisions above 
023and replace  them with the notice and other provisions required by the GPL License.  
024If you do not delete the provisions above, a recipient may use your version of 
025this file under either the MPL or the GPL. 
026
027 */
028package ca.uhn.hl7v2.model;
029
030import ca.uhn.hl7v2.HL7Exception;
031
032/**
033 * Represents an HL7 message segment, which is a unit of data that contains multiple fields.
034 * @author Bryan Tripp (bryan_tripp@sourceforge.net)
035 */
036public interface Segment extends Structure {
037
038    /**
039     * Encodes this message using the parser returned by {@link Message#getParser() }
040     */
041    public String encode() throws HL7Exception;
042
043    /**
044     * Returns the array of Fields at the specified index.  The array will be of length 1 for
045     * non-repeating fields, and >1 for repeating fields.  Fields are numbered from 1.
046     * @throws HL7Exception if field index is out of range.
047     */
048    public Type[] getField(int number) throws HL7Exception;
049
050    /**
051     * Returns a specific repetition of field at the specified index.  If there exist
052     * fewer repetitions than are required, the number of repetitions can be increased
053     * by specifying the lowest repetition that does not yet exist.  For example
054     * if there are two repetitions but three are needed, the third can be created
055     * and accessed using the following code: <br>
056     * <code>Type t = getField(x, 2);</code>
057     * @param number the field number (starting at 1)
058     * @param rep the repetition number (starting at 0)
059     * @throws HL7Exception if field index is out of range, or if the specified
060     *    repetition is more than 1 greater than the highest index of existing repetitions.
061     *    NOTE: to facilitate local extensions, no exception is thrown if
062     *    rep > max cardinality
063     */
064    public Type getField(int number, int rep) throws HL7Exception;
065
066    /**
067     * Returns the maximum length of the field at the given index, in characters.
068     * @throws HL7Exception if field index is out of range.
069     */
070    public int getLength(int number) throws HL7Exception;
071
072    /**
073     * Returns the maximum number of repetitions of this field that are allowed.
074     * The current cardinality can be obtained by checking the length
075     * of the array returned by getLength(n).
076     * @throws HL7Exception if field index is out of range.
077     */
078    public int getMaxCardinality(int number) throws HL7Exception;
079
080    /**
081     * Returns the names of the fields in this segment.
082     *
083     * @since 1.0 - Note that if user defined types are being used, there is a possibility that some entries may be null. All official hapi structures will have all entries populated, but older user defined structures may not have populated all values, since this feature did not exist prior to release 1.0.
084     */
085    public String[] getNames();
086
087    /**
088     * Returns true if the field at the given index is required, false otherwise.
089     * @throws HL7Exception if field index is out of range.
090     */
091    public boolean isRequired(int number) throws HL7Exception;
092
093
094    /**
095     * Returns the number of fields defined by this segment (repeating
096     * fields are not counted multiple times).
097     */
098    public int numFields();
099
100
101    /**
102     * Parses the string into this segment using the parser returned by {@link Message#getParser() }
103     */
104    public void parse(String string) throws HL7Exception;
105
106    
107}