net.codestory.http.templating.helpers.EachReverseHelperSource.java Source code

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Here is the source code for net.codestory.http.templating.helpers.EachReverseHelperSource.java

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/**
 * Copyright (C) 2013 all@code-story.net
 *
 * 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 net.codestory.http.templating.helpers;

import java.io.*;
import java.util.*;

import org.apache.commons.lang3.*;

import com.github.jknack.handlebars.*;

public class EachReverseHelperSource {
    public CharSequence each_reverse(Object context, Options options) throws IOException {
        if (context == null) {
            return StringUtils.EMPTY;
        }

        return (context instanceof Iterable<?>) ? iterableContext((Iterable<?>) context, options)
                : hashContext(context, options);
    }

    private CharSequence hashContext(Object context, Options options) throws IOException {
        StringBuilder buffer = new StringBuilder();

        Context parent = options.context;
        Iterator<Map.Entry<String, Object>> iterator = reverse(options.propertySet(context));
        while (iterator.hasNext()) {
            Map.Entry<String, Object> entry = iterator.next();
            Context current = Context.newContext(parent, entry.getValue()).data("key", entry.getKey());
            buffer.append(options.fn(current));
        }

        return buffer;
    }

    private CharSequence iterableContext(Iterable<?> context, Options options) throws IOException {
        if (options.isFalsy(context)) {
            return options.inverse();
        }

        StringBuilder buffer = new StringBuilder();

        Iterator<?> iterator = reverse(context);
        int index = 0;
        Context parent = options.context;
        while (iterator.hasNext()) {
            Object element = iterator.next();

            boolean first = index == 0;
            boolean even = index % 2 == 0;
            boolean last = !iterator.hasNext();

            Context current = Context.newContext(parent, element).data("index", index)
                    .data("first", first ? "first" : "").data("last", last ? "last" : "")
                    .data("odd", even ? "" : "odd").data("even", even ? "even" : "");
            buffer.append(options.fn(current));

            index++;
        }

        return buffer;
    }

    private static <T> Iterator<T> reverse(Iterable<T> values) {
        LinkedList<T> reversed = new LinkedList<>();
        for (T value : values) {
            reversed.add(value);
        }
        return reversed.descendingIterator();
    }
}