/*
* Copyright 2009 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.gwt.uibinder.parsers;
import com.google.gwt.core.ext.UnableToCompleteException;
import com.google.gwt.uibinder.parsers.FieldReferenceConverter.Delegate;
import com.google.gwt.uibinder.parsers.FieldReferenceConverter.IllegalFieldReferenceException;
import com.google.gwt.uibinder.rebind.UiBinderWriter;
/**
* Fall through attribute parser. Accepts a field reference or nothing.
*/
public class StrictAttributeParser implements AttributeParser {
/**
* Package protected for testing
*/
static class FieldReferenceDelegate implements Delegate {
boolean sawReference = false;
public String handleFragment(String fragment)
throws IllegalFieldReferenceException {
if (fragment.length() > 0) {
throw new IllegalFieldReferenceException();
}
return fragment;
}
public String handleReference(String reference)
throws IllegalFieldReferenceException {
assertOnly();
sawReference = true;
return reference;
}
private void assertOnly() {
if (sawReference) {
throw new IllegalFieldReferenceException();
}
}
}
/**
* If the value holds a single field reference "{like.this}", converts it to a
* Java Expression.
* <p>
* In any other case (e.g. more than one field reference), an
* UnableToCompleteException is thrown.
*/
public String parse(String value, UiBinderWriter writer)
throws UnableToCompleteException {
try {
return new FieldReferenceConverter(new FieldReferenceDelegate()).convert(value);
} catch (IllegalFieldReferenceException e) {
writer.die("Bad field reference: \"%s\"", value);
return null; // Unreachable
}
}
}