/**
* Copyright 2010 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 org.waveprotocol.wave.model.experimental.schema;
import org.waveprotocol.wave.model.util.Utf16Util;
import org.waveprotocol.wave.model.util.Utf16Util.CodePointHandler;
import java.util.Set;
/**
* A validator of characters.
*
*/
final class CharacterValidator {
private interface Predicate {
boolean apply(int codePoint);
}
private static final class ValidatingHandler implements CodePointHandler<Integer> {
private int count = 0;
private final Predicate predicate;
ValidatingHandler(Predicate predicate) {
this.predicate = predicate;
}
@Override
public Integer codePoint(int cp) {
if (!predicate.apply(cp)) {
return count;
}
++count;
return null;
}
@Override
public Integer unpairedSurrogate(char c) {
return count;
}
@Override
public Integer endOfString() {
return -1;
}
}
private final Predicate predicate;
private CharacterValidator(Predicate predicate) {
this.predicate = predicate;
}
/**
* Checks whether the given characters are valid.
*
* @param characters the characters to check
* @return -1 if the characters are all valid, or otherwise the number of
* valid Unicode characters before the first invalid character
*/
int validate(String characters) {
return Utf16Util.traverseUtf16String(characters, new ValidatingHandler(predicate));
}
/**
* Creates a <code>CharacterValidator</code> which blacklists characters.
*
* @param disallowedCharacters the blacklisted characters
* @return the constructed <code>CharacterValidator</code>
*/
static CharacterValidator disallowedCharacters(final Set<Integer> disallowedCharacters) {
return new CharacterValidator(new Predicate() {
@Override
public boolean apply(int codePoint) {
return !disallowedCharacters.contains(codePoint);
}
});
}
/**
* Creates a <code>CharacterValidator</code> which whitelists characters.
*
* @param allowedCharacters the whitelisted characters
* @return the constructed <code>CharacterValidator</code>
*/
static CharacterValidator allowedCharacters(final Set<Integer> allowedCharacters) {
return new CharacterValidator(new Predicate() {
@Override
public boolean apply(int codePoint) {
return allowedCharacters.contains(codePoint);
}
});
}
}