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Diffstat (limited to 'projects/net.wotonomy.web/src/main/java/net/wotonomy/web/WOAssociation.java')
| -rw-r--r-- | projects/net.wotonomy.web/src/main/java/net/wotonomy/web/WOAssociation.java | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/projects/net.wotonomy.web/src/main/java/net/wotonomy/web/WOAssociation.java b/projects/net.wotonomy.web/src/main/java/net/wotonomy/web/WOAssociation.java new file mode 100644 index 0000000..608f9fa --- /dev/null +++ b/projects/net.wotonomy.web/src/main/java/net/wotonomy/web/WOAssociation.java @@ -0,0 +1,168 @@ +/* +Wotonomy: OpenStep design patterns for pure Java applications. +Copyright (C) 2000 Blacksmith, Inc. + +This library is free software; you can redistribute it and/or +modify it under the terms of the GNU Lesser General Public +License as published by the Free Software Foundation; either +version 2.1 of the License, or (at your option) any later version. + +This library is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +Lesser General Public License for more details. + +You should have received a copy of the GNU Lesser General Public +License along with this library; if not, see http://www.gnu.org +*/ + +package net.wotonomy.web; + +/** +* A pure java implementation of WOAssociation. <br><br> +* +* A WOAssociation represents the mapping of a property on a +* WOComponent to a property on a WOAssociation. For example: <br><br> +* +* MyAssociation: WOString { value = currentCustomer.location.city }; <br><br> +* +* This example represents a WOAssociation between the value field +* on a WOString element and the city property of the location property +* of the currentCustomer property of a WOComponent. <br><br> +* +* To resolve values, a property accessor method will be used in +* preference to a public field, if both exist. Any null value +* in the path will produce null. <br><br> +* +* A mapping represented in quotation marks: { value = "This is a test." } +* is considered a constant value. +* +* @author michael@mpowers.net +* @author $Author: cgruber $ +* @version $Revision: 893 $ +*/ +public class WOAssociation implements java.io.Serializable +{ + protected Object value; + protected String path; + + /** + * The default constructor. The static factory methods should + * be used to create instances of WOAssociation. + */ + protected WOAssociation () + { + value = null; + path = null; + } + + /** + * Creates a WOAssociation that maps to a constant value. + */ + public static WOAssociation associationWithValue (Object anObject) + { + WOAssociation result = new WOAssociation(); + result.value = anObject; + return result; + } + + /** + * Creates a WOAssociation that maps to the specified key path. + * If the path is null, the association will map to null. + * Throws an exception if the property cannot be resolved. + */ + public static WOAssociation associationWithKeyPath (String aString) + { + WOAssociation result = new WOAssociation(); + result.path = aString; + return result; + } + + /** + * Returns the value for this association's key path in the + * specified component, or null if any value in the path is + * null or if the key path is null. + */ + public Object valueInComponent (WOComponent aComponent) + { + if ( aComponent == null ) return null; + if ( value != null ) return value; + if ( path != null ) return aComponent.valueForKey( path ); + throw new RuntimeException( + "WOAssociation: neither value nor path specified!" ); + } + + /** + * Sets the property in the specified component to the specified value. + * Throws an exception if the property cannot be resolved. + */ + public void setValue (Object aValue, WOComponent aComponent) + { + if ( path != null ) + { + aComponent.takeValueForKey( aValue, path ); + return; + } + throw new RuntimeException( + "WOAssociation: tried to set value but no path was specified!" ); + } + + /** + * Returns true if this association is writable; that is, + * returns true if this association is not constant. + */ + public boolean isValueSettable () + { + return ( path != null ); + } + + /** + * Returns true if this association is constant + * and therefore read-only. + */ + public boolean isValueConstant () + { + return ( path == null ); + } + + /** + * For debugging purposes. + */ + public String toString() + { + if ( path != null ) + { + return "[WOAssociation:" + path + "]"; + } + return "[WOAssociation:\"" + value + "\"]"; + } +} + +/* + * $Log$ + * Revision 1.1 2006/02/16 13:22:22 cgruber + * Check in all sources in eclipse-friendly maven-enabled packages. + * + * Revision 1.6 2003/01/24 20:13:22 mpowers + * Now accepting immutable NSDictionary in constructor, not Map. + * + * Revision 1.5 2003/01/17 22:55:08 mpowers + * Straighted out the parent binding issue (I think). + * Fixes for woextensions compatibility. + * + * Revision 1.3 2003/01/15 19:50:49 mpowers + * Fixed issues with WOSession and Serializable. + * Can now persist sessions between classloaders (hot swap of class impls). + * + * Revision 1.2 2003/01/14 15:51:48 mpowers + * Removed value() method from WOAssociaton. + * + * Revision 1.1.1.1 2000/12/21 15:52:50 mpowers + * Contributing wotonomy. + * + * Revision 1.3 2000/12/20 16:25:49 michael + * Added log to all files. + * + * + */ + |