* Abstract superclass for 'association' classes. Associations define how * dynamic elements (stateless, non-WOComponent template elements) pull and * push their 'bindings'. *
* The most common subclasses are
* Prefixes:
* WOKeyPathAssociation, which
* pushes/pulls values into/from the current component in the context,
* and WOValueAssociation, which just wraps a constant value in
* the WOAssociation API.
*
* But in addition there are associations which evaluate OGNL expressions,
* which resolve their value as localization keys or which resolve string
* patterns in a certain context. etc etc
*/
public abstract class WOAssociation extends NSObject
implements IWOAssociation
{
protected static final Log log = LogFactory.getLog("WOAssociations");
/**
* Factory method which returns an association which pulls/pushes values
* from the current component using KVC (key/value coding).
* Per default this is the WOKeyPathAssociation class.
*
* @param _keyPath - the keypath (eg "person.address.city")
* @return the WOAssociation, usually a WOKeyPathAssociation
*/
public static WOAssociation associationWithKeyPath(String _keyPath) {
if (_keyPath != null && _keyPath.indexOf('.') < 0) {
// TBD: we could even have a few hardcoded assoc keys, eg 'item' to save
// objects
return new WOKeyAssociation(_keyPath);
}
return new WOKeyPathAssociation(_keyPath);
}
/**
* Factory method which returns an association that wraps a constant in the
* association interface. The constants are usually - but not necessarily -
* simple objects, like Strings or Numbers or property list objects (Map,
* List).
*
* Per default this is the WOValueAssociation class.
*
* @param _value - the value, eg a String or a Number or a Map
* @return the WOAssociation, usually a WOValueAssociation
*/
public static WOAssociation associationWithValue(Object _value) {
return new WOValueAssociation(_value);
}
/* accessors */
/**
* Returns a KVC keypath associated with the WOAssociation. Or nothing if the
* association is unrelated with KVC.
*
* @return the keypath of the association
*/
public abstract String keyPath();
/* reflection */
/**
* Returns true if the association always returns the same value. This can be
* used by dynamic elements to cache the value (and discard the association
* wrapper).
*
* @return true if the value of the association never changes, false otherwise
*/
public boolean isValueConstant() {
return false;
}
/**
* Returns true if the association accepts new values. Eg a constant
* association obviously doesn't accept new values. A KVC association to a
* target which does not have a set accessor could also return
* false (but currently does not ...).
*
* @return true if the value of the association can be set, false otherwise
*/
public boolean isValueSettable() {
return true;
}
/**
* Returns true if the association always returns the same value for the
* specified cursor (usually a component). This can be used by dynamic
* elements to cache the value.
*
* @return true if the value of the association does not change
*/
public boolean isValueConstantInComponent(Object _cursor) {
return this.isValueConstant();
}
/**
* Returns true if the association can accept new values for the given cursor
* (usually a WOComponent). A KVC association to a target which does not have
* a set accessor could also return false (but currently does
* not ...).
*
* @return true if the value of the association can be set, false otherwise
*/
public boolean isValueSettableInComponent(Object _cursor) {
return this.isValueSettable();
}
/* values */
public void setValue(Object _value, Object _cursor) {
/* Note: crappy name due to WO compatibility */
}
public Object valueInComponent(Object _cursor) {
return null;
}
/* specific values */
public void setBooleanValue(boolean _value, Object _cursor) {
this.setValue(_value ? Boolean.TRUE : Boolean.FALSE, _cursor);
}
public boolean booleanValueInComponent(Object _cursor) {
return UObject.boolValue(this.valueInComponent(_cursor));
}
public void setIntValue(int _value, Object _cursor) {
this.setValue(new Integer(_value), _cursor);
}
public int intValueInComponent(Object _cursor) {
return UObject.intValue(this.valueInComponent(_cursor));
}
public void setStringValue(String _value, Object _cursor) {
this.setValue(_value, _cursor);
}
public String stringValueInComponent(Object _cursor) {
Object v = this.valueInComponent(_cursor);
if (v == null)
return null;
if (v instanceof String)
return (String)v;
return v.toString();
}
/* prefix registry */
protected static ConcurrentHashMap
*
* If no prefix matches, associationWithValue will be used.
*
* @param _prefix - the parsed prefix which denotes the association class
* @param _name - the name of the binding (not relevant in this imp)
* @param _value - the value which needs to be put into the context
*/
public static WOAssociation associationForPrefix
(String _prefix, String _name, String _value)
{
// TBD: its suboptimal that we refer to the associations subpackage. We
// probably want to have a configurable HashMap
WOAssociation assoc = null;
char c = _prefix.charAt(0);
switch (c) {
case 'c':
if (_prefix.equals("const"))
assoc = associationWithValue(_value);
break;
case 'j':
if (_prefix.equals("jo"))
assoc = new JoPathAssociation(_value);
break;
case 'l':
if (_prefix.equals("label"))
assoc = new WOLabelAssociation(_value);
break;
case 'o':
if (_prefix.equals("ognl"))
assoc = new WOOgnlAssociation(_value);
break;
case 'p':
if (_prefix.equals("plist")) {
/* Allow arrays like this: list="(a,b,c)",
* required because we can't specify plists in .html
* template attributes. (we might want to change that?)
*/
NSPropertyListParser parser = new NSPropertyListParser();
Object v = parser.parse(_value);
if (v == null) {
log.warn("could not parse plist value of association: " + _value,
parser.lastException());
assoc = null;
}
else
assoc = associationWithValue(v);
}
break;
case 'q':
if (_prefix.equals("q"))
assoc = new WOQualifierAssociation(_value);
break;
case 'r':
if (_prefix.equals("rsrc"))
assoc = new WOResourceURLAssociation(_value);
else if (_prefix.equals("regex"))
assoc = new WORegExAssociation(_value);
break;
case 'v':
if (_prefix.equals("var")) {
if (_value == null || _value.length() == 0) {
log.error("got var: association w/o keypath: " + _name);
assoc = associationWithValue
("[binding '"+ _name + "' has no value]");
}
else
assoc = associationWithKeyPath(_value);
}
else if (_prefix.equals("varpat"))
assoc = new WOKeyPathPatternAssociation(_value);
break;
}
if (assoc == null) {
Class clazz = prefixToAssoc.get(_prefix);
if (clazz != null)
assoc = (WOAssociation)NSJavaRuntime.NSAllocateObject(clazz, _value);
}
if (assoc == null) /* default to value assoc */
assoc = associationWithValue(_value);
return assoc;
}
}