File	Doc	Category	Size	Date	Package
CompositeELResolver.java	API Doc	Glassfish v2 API	22267	Fri Feb 17 14:04:50 GMT 2006	javax.el

CompositeELResolver

• java.lang.Object
  • javax.el.ELResolver

Fields Summary
private final ArrayList	elResolvers

Constructors Summary

Methods Summary
public void	add(javax.el.ELResolver elResolver) Adds the given resolver to the list of component resolvers. Resolvers are consulted in the order in which they are added. param elResolver The component resolver to add. throws NullPointerException If the provided resolver is null. if (elResolver == null) { throw new NullPointerException(); } elResolvers.add(elResolver);
public java.lang.Class	getCommonPropertyType(javax.el.ELContext context, java.lang.Object base) Returns the most general type that this resolver accepts for the property argument, given a base object. One use for this method is to assist tools in auto-completion. The result is obtained by querying all component resolvers. The Class returned is the most specific class that is a common superclass of all the classes returned by each component resolver's getCommonPropertyType method. If null is returned by a resolver, it is skipped. param context The context of this evaluation. param base The base object to return the most general property type for, or null to enumerate the set of top-level variables that this resolver can evaluate. return null if this ELResolver does not know how to handle the given base object; otherwise Object.class if any type of property is accepted; otherwise the most general property type accepted for the given base. Class<?> commonPropertyType = null; Iterator<ELResolver> iter = elResolvers.iterator(); while (iter.hasNext()) { ELResolver elResolver = iter.next(); Class<?> type = elResolver.getCommonPropertyType(context, base); if (type == null) { // skip this EL Resolver continue; } else if (commonPropertyType == null) { commonPropertyType = type; } else if (commonPropertyType.isAssignableFrom(type)) { continue; } else if (type.isAssignableFrom(commonPropertyType)) { commonPropertyType = type; } else { // Don't have a commonPropertyType return null; } } return commonPropertyType;
public java.util.Iterator	getFeatureDescriptors(javax.el.ELContext context, java.lang.Object base) Returns information about the set of variables or properties that can be resolved for the given base object. One use for this method is to assist tools in auto-completion. The results are collected from all component resolvers. The propertyResolved property of the ELContext is not relevant to this method. The results of all ELResolvers are concatenated. The Iterator returned is an iterator over the collection of FeatureDescriptor objects returned by the iterators returned by each component resolver's getFeatureDescriptors method. If null is returned by a resolver, it is skipped. param context The context of this evaluation. param base The base object whose set of valid properties is to be enumerated, or null to enumerate the set of top-level variables that this resolver can evaluate. return An Iterator containing zero or more (possibly infinitely more) FeatureDescriptor objects, or null if this resolver does not handle the given base object or that the results are too complex to represent with this method return new CompositeIterator(elResolvers.iterator(), context, base);
public java.lang.Class	getType(javax.el.ELContext context, java.lang.Object base, java.lang.Object property) For a given base and property, attempts to identify the most general type that is acceptable for an object to be passed as the value parameter in a future call to the {@link #setValue} method. The result is obtained by querying all component resolvers. If this resolver handles the given (base, property) pair, the propertyResolved property of the ELContext object must be set to true by the resolver, before returning. If this property is not true after this method is called, the caller should ignore the return value. First, propertyResolved is set to false on the provided ELContext. Next, for each component resolver in this composite: The getType() method is called, passing in the provided context, base and property. If the ELContext's propertyResolved flag is false then iteration continues. Otherwise, iteration stops and no more component resolvers are considered. The value returned by getType() is returned by this method. If none of the component resolvers were able to perform this operation, the value null is returned and the propertyResolved flag remains set to false . Any exception thrown by component resolvers during the iteration is propagated to the caller of this method. param context The context of this evaluation. param base The base object whose property value is to be analyzed, or null to analyze a top-level variable. param property The property or variable to return the acceptable type for. return If the propertyResolved property of ELContext was set to true, then the most general acceptable type; otherwise undefined. throws NullPointerException if context is null throws PropertyNotFoundException if the given (base, property) pair is handled by this ELResolver but the specified variable or property does not exist or is not readable. throws ELException if an exception was thrown while performing the property or variable resolution. The thrown exception must be included as the cause property of this exception, if available. context.setPropertyResolved(false); int i = 0, len = this.elResolvers.size(); ELResolver elResolver; Class<?> type; while (i < len) { elResolver = this.elResolvers.get(i); type = elResolver.getType(context, base, property); if (context.isPropertyResolved()) { return type; } i++; } return null;
public java.lang.Object	getValue(javax.el.ELContext context, java.lang.Object base, java.lang.Object property) Attempts to resolve the given property object on the given base object by querying all component resolvers. If this resolver handles the given (base, property) pair, the propertyResolved property of the ELContext object must be set to true by the resolver, before returning. If this property is not true after this method is called, the caller should ignore the return value. First, propertyResolved is set to false on the provided ELContext. Next, for each component resolver in this composite: The getValue() method is called, passing in the provided context, base and property. If the ELContext's propertyResolved flag is false then iteration continues. Otherwise, iteration stops and no more component resolvers are considered. The value returned by getValue() is returned by this method. If none of the component resolvers were able to perform this operation, the value null is returned and the propertyResolved flag remains set to false . Any exception thrown by component resolvers during the iteration is propagated to the caller of this method. param context The context of this evaluation. param base The base object whose property value is to be returned, or null to resolve a top-level variable. param property The property or variable to be resolved. return If the propertyResolved property of ELContext was set to true, then the result of the variable or property resolution; otherwise undefined. throws NullPointerException if context is null throws PropertyNotFoundException if the given (base, property) pair is handled by this ELResolver but the specified variable or property does not exist or is not readable. throws ELException if an exception was thrown while performing the property or variable resolution. The thrown exception must be included as the cause property of this exception, if available. context.setPropertyResolved(false); int i = 0, len = this.elResolvers.size(); ELResolver elResolver; Object value; while (i < len) { elResolver = this.elResolvers.get(i); value = elResolver.getValue(context, base, property); if (context.isPropertyResolved()) { return value; } i++; } return null;
public boolean	isReadOnly(javax.el.ELContext context, java.lang.Object base, java.lang.Object property) For a given base and property, attempts to determine whether a call to {@link #setValue} will always fail. The result is obtained by querying all component resolvers. If this resolver handles the given (base, property) pair, the propertyResolved property of the ELContext object must be set to true by the resolver, before returning. If this property is not true after this method is called, the caller should ignore the return value. First, propertyResolved is set to false on the provided ELContext. Next, for each component resolver in this composite: The isReadOnly() method is called, passing in the provided context, base and property. If the ELContext's propertyResolved flag is false then iteration continues. Otherwise, iteration stops and no more component resolvers are considered. The value returned by isReadOnly() is returned by this method. If none of the component resolvers were able to perform this operation, the value false is returned and the propertyResolved flag remains set to false . Any exception thrown by component resolvers during the iteration is propagated to the caller of this method. param context The context of this evaluation. param base The base object whose property value is to be analyzed, or null to analyze a top-level variable. param property The property or variable to return the read-only status for. return If the propertyResolved property of ELContext was set to true, then true if the property is read-only or false if not; otherwise undefined. throws NullPointerException if context is null throws PropertyNotFoundException if the given (base, property) pair is handled by this ELResolver but the specified variable or property does not exist. throws ELException if an exception was thrown while performing the property or variable resolution. The thrown exception must be included as the cause property of this exception, if available. context.setPropertyResolved(false); int i = 0, len = this.elResolvers.size(); ELResolver elResolver; boolean readOnly; while (i < len) { elResolver = this.elResolvers.get(i); readOnly = elResolver.isReadOnly(context, base, property); if (context.isPropertyResolved()) { return readOnly; } i++; } return false; // Does not matter
public void	setValue(javax.el.ELContext context, java.lang.Object base, java.lang.Object property, java.lang.Object val) Attempts to set the value of the given property object on the given base object. All component resolvers are asked to attempt to set the value. If this resolver handles the given (base, property) pair, the propertyResolved property of the ELContext object must be set to true by the resolver, before returning. If this property is not true after this method is called, the caller can safely assume no value has been set. First, propertyResolved is set to false on the provided ELContext. Next, for each component resolver in this composite: The setValue() method is called, passing in the provided context, base, property and value. If the ELContext's propertyResolved flag is false then iteration continues. Otherwise, iteration stops and no more component resolvers are considered. If none of the component resolvers were able to perform this operation, the propertyResolved flag remains set to false . Any exception thrown by component resolvers during the iteration is propagated to the caller of this method. param context The context of this evaluation. param base The base object whose property value is to be set, or null to set a top-level variable. param property The property or variable to be set. param val The value to set the property or variable to. throws NullPointerException if context is null throws PropertyNotFoundException if the given (base, property) pair is handled by this ELResolver but the specified variable or property does not exist. throws PropertyNotWritableException if the given (base, property) pair is handled by this ELResolver but the specified variable or property is not writable. throws ELException if an exception was thrown while attempting to set the property or variable. The thrown exception must be included as the cause property of this exception, if available. context.setPropertyResolved(false); int i = 0, len = this.elResolvers.size(); ELResolver elResolver; while (i < len) { elResolver = this.elResolvers.get(i); elResolver.setValue(context, base, property, val); if (context.isPropertyResolved()) { return; } i++; }