/**
* 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 org.waveprotocol.wave.model.document.operation.algorithm;
import org.waveprotocol.wave.model.document.operation.AnnotationBoundaryMap;
import org.waveprotocol.wave.model.document.operation.Attributes;
import org.waveprotocol.wave.model.document.operation.AttributesUpdate;
import org.waveprotocol.wave.model.document.operation.EvaluatingDocOpCursor;
/**
* A normalizer for mutation events that affect ranges.
*
* @param <T> the type of the value returned by the normalizer
*/
public final class RangeNormalizer<T> implements EvaluatingDocOpCursor<T> {
private abstract class Cache {
abstract void flush();
public void skip(int distance) {
flush();
cache = skipCache;
cache.skip(distance);
}
public void characters(String characters) {
flush();
cache = charactersCache;
cache.characters(characters);
}
public void deleteCharacters(String characters) {
flush();
cache = deleteCharactersCache;
cache.deleteCharacters(characters);
}
}
private final Cache emptyCache = new Cache() {
@Override
public void flush() {}
};
private final Cache skipCache = new Cache() {
int distance = 0;
@Override
public void flush() {
target.retain(distance);
distance = 0;
cache = emptyCache;
}
@Override
public void skip(int distance) {
this.distance += distance;
}
};
private final Cache charactersCache = new Cache() {
StringBuilder characters = new StringBuilder();
@Override
public void flush() {
target.characters(characters.toString());
characters = new StringBuilder();
cache = emptyCache;
}
@Override
public void characters(String characters) {
this.characters.append(characters);
}
};
private final Cache deleteCharactersCache = new Cache() {
StringBuilder characters = new StringBuilder();
@Override
public void flush() {
target.deleteCharacters(characters.toString());
characters = new StringBuilder();
cache = emptyCache;
}
@Override
public void deleteCharacters(String characters) {
this.characters.append(characters);
}
};
private final EvaluatingDocOpCursor<? extends T> target;
private Cache cache = emptyCache;
public RangeNormalizer(EvaluatingDocOpCursor<? extends T> target) {
this.target = target;
}
@Override
public T finish() {
cache.flush();
return target.finish();
}
@Override
public void retain(int itemCount) {
if (itemCount > 0) {
cache.skip(itemCount);
}
}
@Override
public void characters(String chars) {
if (!chars.isEmpty()) {
cache.characters(chars);
}
}
@Override
public void elementStart(String type, Attributes attrs) {
cache.flush();
target.elementStart(type, attrs);
}
@Override
public void elementEnd() {
cache.flush();
target.elementEnd();
}
@Override
public void deleteCharacters(String chars) {
if (!chars.isEmpty()) {
cache.deleteCharacters(chars);
}
}
@Override
public void deleteElementStart(String type, Attributes attrs) {
cache.flush();
target.deleteElementStart(type, attrs);
}
@Override
public void deleteElementEnd() {
cache.flush();
target.deleteElementEnd();
}
@Override
public void replaceAttributes(Attributes oldAttrs, Attributes newAttrs) {
cache.flush();
target.replaceAttributes(oldAttrs, newAttrs);
}
@Override
public void updateAttributes(AttributesUpdate attrUpdate) {
cache.flush();
target.updateAttributes(attrUpdate);
}
@Override
public void annotationBoundary(AnnotationBoundaryMap map) {
cache.flush();
target.annotationBoundary(map);
}
}