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// Copyright (C) 2009 The Android Open Source Project
//
// 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.gwtexpui.safehtml.client;
import static java.util.Comparator.comparing;
import static java.util.stream.Collectors.toList;
import com.google.gwt.user.client.ui.SuggestOracle;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
/**
* A suggestion oracle that tries to highlight the matched text.
*
* <p>Suggestions supplied by the implementation of {@link #onRequestSuggestions(Request, Callback)}
* are modified to wrap all occurrences of the {@link
* com.google.gwt.user.client.ui.SuggestOracle.Request#getQuery()} substring in HTML {@code
* <strong>} tags, so they can be emphasized to the user.
*/
public abstract class HighlightSuggestOracle extends SuggestOracle {
private static String escape(String ds) {
return new SafeHtmlBuilder().append(ds).asString();
}
@Override
public final boolean isDisplayStringHTML() {
return true;
}
@Override
public final void requestSuggestions(Request request, Callback cb) {
onRequestSuggestions(
request,
new Callback() {
@Override
public void onSuggestionsReady(Request request, Response response) {
final String qpat = getQueryPattern(request.getQuery());
final boolean html = isHTML();
final ArrayList<Suggestion> r = new ArrayList<>();
for (Suggestion s : response.getSuggestions()) {
r.add(new BoldSuggestion(qpat, s, html));
}
cb.onSuggestionsReady(request, new Response(r));
}
});
}
protected String getQueryPattern(String query) {
return query;
}
/**
* @return true if {@link
* com.google.gwt.user.client.ui.SuggestOracle.Suggestion#getDisplayString()} returns HTML;
* false if the text must be escaped before evaluating in an HTML like context.
*/
protected boolean isHTML() {
return false;
}
/** Compute the suggestions and return them for display. */
protected abstract void onRequestSuggestions(Request request, Callback done);
private static class BoldSuggestion implements Suggestion {
private final Suggestion suggestion;
private final String displayString;
BoldSuggestion(String qstr, Suggestion s, boolean html) {
suggestion = s;
String ds = s.getDisplayString();
if (!html) {
ds = escape(ds);
}
if (qstr != null && !qstr.isEmpty()) {
StringBuilder pattern = new StringBuilder();
for (String qterm : splitQuery(qstr)) {
qterm = escape(qterm);
// We now surround qstr by <strong>. But the chosen approach is not too
// smooth, if qstr is small (e.g.: "t") and this small qstr may occur in
// escapes (e.g.: "Tim <email@example.org>"). Those escapes will
// get <strong>-ed as well (e.g.: "<" -> "&<strong>l</strong>t;"). But
// as repairing those mangled escapes is easier than not mangling them in
// the first place, we repair them afterwards.
if (pattern.length() > 0) {
pattern.append("|");
}
pattern.append(qterm);
}
ds = sgi(ds, "(" + pattern.toString() + ")", "<strong>$1</strong>");
// Repairing <strong>-ed escapes.
ds = sgi(ds, "(&[a-z]*)<strong>([a-z]*)</strong>([a-z]*;)", "$1$2$3");
}
displayString = ds;
}
/**
* Split the query by whitespace and filter out query terms which are substrings of other query
* terms.
*/
private static List<String> splitQuery(String query) {
List<String> queryTerms =
Arrays.stream(query.split("\\s+")).sorted(comparing(String::length)).collect(toList());
List<String> result = new ArrayList<>();
for (String s : queryTerms) {
boolean add = true;
for (String queryTerm : result) {
if (queryTerm.toLowerCase().contains(s.toLowerCase())) {
add = false;
break;
}
}
if (add) {
result.add(s);
}
}
return result;
}
private static native String sgi(String inString, String pat, String newHtml)
/*-{ return inString.replace(RegExp(pat, 'gi'), newHtml); }-*/ ;
@Override
public String getDisplayString() {
return displayString;
}
@Override
public String getReplacementString() {
return suggestion.getReplacementString();
}
}
}
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