Annotation of libwww/Library/src/HTLink.html, revision 2.1
2.1 ! frystyk 1: <HTML>
! 2: <HEAD>
! 3: <!-- Changed by: Henrik Frystyk Nielsen, 30-Jun-1996 -->
! 4: <TITLE>W3C Reference Library libwww Link Class</TITLE>
! 5: </HEAD>
! 6: <BODY>
! 7: <H1>
! 8: The Link Class
! 9: </H1>
! 10: <PRE>
! 11: /*
! 12: ** (c) COPYRIGHT MIT 1995.
! 13: ** Please first read the full copyright statement in the file COPYRIGH.
! 14: */
! 15: </PRE>
! 16: <P>
! 17: A <A HREF="HTLink.html">Link</A> represents the link between anchor objects.
! 18: By keeping the link as a object and not as part of the anchor we are capable
! 19: of handling link semantics in a much more organized way. For example, we
! 20: can then search for link types among all the link objects that we have created.
! 21: <A HREF="HTAnchor.html">Anchor objects</A> are bound together using Link
! 22: objects. Each anchor can be the source or destination of zero, one, or more
! 23: links from and to other anchors.
! 24: <P>
! 25: This module is implemented by <A HREF="HTLink.c">HTLink.c</A>, and it is
! 26: a part of the <A HREF="http://www.w3.org/pub/WWW/Library/"> W3C Reference
! 27: Library</A>.
! 28: <PRE>
! 29: #ifndef HTLINK_H
! 30: #define HTLINK_H
! 31:
! 32: typedef struct _HTLink HTLink;
! 33:
! 34: #include "WWWUtil.h"
! 35: #include "HTMethod.h"
! 36: #include "HTAnchor.h"
! 37: </PRE>
! 38: <H2>
! 39: Creation and Deletion Methods
! 40: </H2>
! 41: <P>
! 42: These are the methods for crating and deleting new link objects
! 43: <H3>
! 44: Create a new Link Object
! 45: </H3>
! 46: <PRE>typedef HTAtom * HTLinkType;
! 47:
! 48: typedef enum _HTLinkResult {
! 49: HT_LINK_INVALID = -1,
! 50: HT_LINK_NONE = 0,
! 51: HT_LINK_ERROR,
! 52: HT_LINK_OK
! 53: } HTLinkResult;
! 54:
! 55: struct _HTLink {
! 56: HTAnchor * dest; /* The anchor to which this leads */
! 57: HTLinkType type; /* Semantics of this link */
! 58: HTMethod method; /* Method for this link, e.g. PUT */
! 59: HTLinkResult result; /* Result of any attempt to get this link */
! 60: };
! 61:
! 62: HTLink * HTLink_new (void);
! 63: </PRE>
! 64: <H3>
! 65: Delete a Link Object
! 66: </H3>
! 67: <P>
! 68: A link can be removed as any other object
! 69: <PRE>BOOL HTLink_delete (HTLink * link);
! 70: </PRE>
! 71: <H3>
! 72: Remove All Link Information from an Anchor
! 73: </H3>
! 74: <P>
! 75: This is normally a part of deleting anchor objects.
! 76: <PRE>extern BOOL HTLink_removeAll (HTAnchor * me);
! 77: </PRE>
! 78: <H2>
! 79: Handle Link Between Anchors
! 80: </H2>
! 81: <P>
! 82: As mentioned, link objects are the ones that bind anchor objects together
! 83: in a Web like structure
! 84: <H3>
! 85: Add a Link between two Anchors
! 86: </H3>
! 87: <P>
! 88: This method creates a new link between two <A HREF="HTAnchor.html">anchor
! 89: objects</A>.
! 90: <PRE>extern BOOL HTLink_add (HTAnchor * source,
! 91: HTAnchor * destination,
! 92: HTLinkType type,
! 93: HTMethod method);
! 94: </PRE>
! 95: <H3>
! 96: Remove All Links Between two Anchors
! 97: </H3>
! 98: <P>
! 99: Removes link information from one anchor to another.
! 100: <PRE>extern BOOL HTLink_remove (HTAnchor * source, HTAnchor * destination);
! 101: </PRE>
! 102: <H3>
! 103: Find a Link
! 104: </H3>
! 105: <P>
! 106: Find the anchor object between a destination and a source ancher. Return
! 107: link object if any, else NULL
! 108: <PRE>extern HTLink * HTLink_find (HTAnchor * source, HTAnchor * destination);
! 109: </PRE>
! 110: <H2>
! 111: Link Information
! 112: </H2>
! 113: <P>
! 114: This is the set of methods for accessing the information carried by a link
! 115: object
! 116: <H3>
! 117: Link Destination
! 118: </H3>
! 119: <P>
! 120: The link destination is the destination anchor pointed to by the link.
! 121: <PRE>extern BOOL HTLink_setDestination (HTLink * link, HTAnchor * dest);
! 122: extern HTAnchor * HTLink_destination (HTLink * link);
! 123: </PRE>
! 124: <H3>
! 125: Link Types and Semantic Links
! 126: </H3>
! 127: <P>
! 128: Each link has a sematic representation associated with it. This means that
! 129: the application can distinguish between pages based on the semantics of the
! 130: link. This is very similar to the <CODE>LINK</CODE> tag in HTML pages which
! 131: indicates the meaning if this pages to other pages.
! 132: <PRE>extern BOOL HTLink_setType (HTLink * link, HTLinkType type);
! 133: extern HTLinkType HTLink_type (HTLink * link);
! 134: </PRE>
! 135: <H3>
! 136: Link Method
! 137: </H3>
! 138: <P>
! 139: The link method is the HTTP method we have performed between the two links.
! 140: For example, it can be a POST operation, or a PUT operation where the operation
! 141: on the first anchor created a new anchor.
! 142: <PRE>extern BOOL HTLink_setMethod (HTLink * link, HTMethod method);
! 143: extern HTMethod HTLink_method (HTLink * link);
! 144: </PRE>
! 145: <H3>
! 146: Link Result
! 147: </H3>
! 148: <P>
! 149: When a link has been used for posting an object from a source to a destination
! 150: link, the result of the operation is stored as part of the link information.
! 151: This means that we can keep track of which operations we have performed on
! 152: a link and hence the application can ask the user whether he or she wants
! 153: to do a re-post, for example.
! 154: <PRE>
! 155: extern BOOL HTLink_setResult (HTLink * link, HTLinkResult result);
! 156: extern HTLinkResult HTLink_result (HTLink * link);
! 157: </PRE>
! 158: <PRE>
! 159: #endif /* HTLINK_H */
! 160: </PRE>
! 161: <P>
! 162: <HR>
! 163: <ADDRESS>
! 164: @(#) $Id: HTAnchor.html,v 2.43 1996/06/03 19:25:02 eric Exp $
! 165: </ADDRESS>
! 166: </BODY></HTML>
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