AbstractSuggestOracle.java

/*
 * Copyright 2008 Jeff Dwyer
 * 
 * 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.apress.progwt.client.suggest;

import com.apress.progwt.client.college.ServiceCache;
import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.SuggestOracle;

public abstract class AbstractSuggestOracle<T> extends SuggestOracle {

    private static HTML convertMe = new HTML();
    private ServiceCache serviceCache;

    public AbstractSuggestOracle(ServiceCache serviceCache) {
        this.serviceCache = serviceCache;

    }

    public ServiceCache getServiceCache() {
        return serviceCache;
    }

    public static String escapeText(String escapeMe) {
        convertMe.setText(escapeMe);
        String escaped = convertMe.getHTML();
        return escaped;
    }

    /**
     * Simpler than the Google MultiWordSuggest highlighter in that it
     * will only highlight the first occurrence
     * 
     * @param candidate
     * @param query
     * @return
     */
    public static String highlight(String candidate, String query) {

        int index = 0;
        int cursor = 0;

        // Create strong search string.
        StringBuffer accum = new StringBuffer();

        query = query.toLowerCase();

        index = candidate.toLowerCase().indexOf(query, index);

        if (index != -1) {

            int endIndex = index + query.length();
            String part1 = escapeText(candidate.substring(cursor, index));
            String part2 = escapeText(candidate
                    .substring(index, endIndex));
            cursor = endIndex;
            accum.append(part1).append("<strong>").append(part2).append(
                    "</strong>");
        }

        // Finish creating the formatted string.
        String end = candidate.substring(cursor);
        accum.append(escapeText(end));

        return accum.toString();
    }

    /**
     * Repsonsible for turning the final string into an object of type T.
     * Some Oracles may choose to simply run anohter requestSuggestions()
     * then take the first element returned. Others (like those that
     * operate on a List<String> instead of List<T> may need to do a
     * separate Async call to load the object.
     * 
     * @param completeStr
     * @param listener
     */
    public abstract void fireCompleteListenerFromCompleteString(
            String completeStr, CompleteListener<T> listener);
}