001    // Copyright 2006, 2007, 2008, 2009, 2010, 2011 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    // http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry5.internal.services;
016    
017    import org.apache.tapestry5.Binding;
018    import org.apache.tapestry5.ComponentResources;
019    import org.apache.tapestry5.ioc.Location;
020    import org.apache.tapestry5.ioc.internal.util.InternalUtils;
021    import org.apache.tapestry5.ioc.internal.util.TapestryException;
022    import org.apache.tapestry5.services.BindingFactory;
023    import org.apache.tapestry5.services.BindingSource;
024    
025    import java.util.Map;
026    
027    public class BindingSourceImpl implements BindingSource
028    {
029        private final Map<String, BindingFactory> factories;
030    
031        private final StringInterner interner;
032    
033        public BindingSourceImpl(Map<String, BindingFactory> factories, StringInterner interner)
034        {
035            this.factories = factories;
036            this.interner = interner;
037        }
038    
039        public Binding newBinding(String description, ComponentResources container, String defaultPrefix, String expression)
040        {
041            return newBinding(description, container, container, defaultPrefix, expression, null);
042        }
043    
044        public Binding newBinding(String description, ComponentResources container, ComponentResources component,
045                                  String defaultPrefix, String expression, Location location)
046        {
047            assert InternalUtils.isNonBlank(description);
048            assert container != null;
049            assert InternalUtils.isNonBlank(defaultPrefix);
050            assert component != null;
051    
052            // TAP5-845: The expression may be the empty string. This is ok, if it's compatible with
053            // the default prefix (the empty string is not a valid property expression, but is valid
054            // as a literal string, perhaps as an informal parameter).
055    
056            // Location might be null
057    
058            String subexpression = expression;
059            int colonx = expression.indexOf(':');
060    
061            BindingFactory factory = null;
062    
063            if (colonx > 0)
064            {
065                String prefix = expression.substring(0, colonx);
066    
067                factory = factories.get(prefix);
068                if (factory != null)
069                    subexpression = expression.substring(colonx + 1);
070            }
071    
072            if (factory == null)
073                factory = factories.get(defaultPrefix);
074    
075            // And if that's null, what then? We assume that the default prefix is a valid prefix,
076            // or we'll get an NPE below and report it like any other error.
077    
078            try
079            {
080                return factory.newBinding(interner.intern(description), container, component, subexpression, location);
081            } catch (Exception ex)
082            {
083                throw new TapestryException(String.format("Could not convert '%s' into a component parameter binding: %s", expression, InternalUtils.toMessage(ex)), location, ex);
084            }
085        }
086    }