org.springframework.social.facebook.api.impl.PagedListUtils.java Source code

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Here is the source code for org.springframework.social.facebook.api.impl.PagedListUtils.java

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/*
 * Copyright 2014 the original author or authors.
 *
 * 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.springframework.social.facebook.api.impl;

import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;

import org.springframework.social.facebook.api.PagingParameters;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;

import com.fasterxml.jackson.databind.JsonNode;

class PagedListUtils {

    public static PagingParameters getPagedListParameters(JsonNode pagingNode, String pageKey) {
        if (pagingNode == null || pagingNode.get(pageKey) == null) {
            return null;
        }
        String pageNode = pagingNode.get(pageKey).textValue();
        String limitString = extractParameterValueFromUrl(pageNode, "limit");
        String sinceString = extractParameterValueFromUrl(pageNode, "since");
        String untilString = extractParameterValueFromUrl(pageNode, "until");
        String offsetString = extractParameterValueFromUrl(pageNode, "offset");
        String after = extractEncodedParameterValueFromUrl(pageNode, "after");
        String before = extractEncodedParameterValueFromUrl(pageNode, "before");

        return new PagingParameters(limitString != null ? Integer.valueOf(limitString) : null,
                offsetString != null ? Integer.valueOf(offsetString) : null,
                sinceString != null ? Long.valueOf(sinceString) : null,
                untilString != null ? Long.valueOf(untilString) : null, after, before);
    }

    public static MultiValueMap<String, String> getPagingParameters(PagingParameters pagedListParameters) {
        MultiValueMap<String, String> parameters = new LinkedMultiValueMap<String, String>();
        if (pagedListParameters.getOffset() != null) {
            parameters.add("offset", String.valueOf(pagedListParameters.getOffset()));
        }
        if (pagedListParameters.getLimit() != null) {
            parameters.add("limit", String.valueOf(pagedListParameters.getLimit()));
        }
        if (pagedListParameters.getSince() != null) {
            parameters.add("since", String.valueOf(pagedListParameters.getSince()));
        }
        if (pagedListParameters.getUntil() != null) {
            parameters.add("until", String.valueOf(pagedListParameters.getUntil()));
        }
        if (pagedListParameters.getBefore() != null) {
            parameters.add("before", String.valueOf(pagedListParameters.getBefore()));
        }
        if (pagedListParameters.getAfter() != null) {
            parameters.add("after", String.valueOf(pagedListParameters.getAfter()));
        }
        return parameters;
    }

    private static String extractEncodedParameterValueFromUrl(String url, String paramName) {
        try {
            String value = extractParameterValueFromUrl(url, paramName);
            return value != null ? URLDecoder.decode(value, "UTF-8") : null;
        } catch (UnsupportedEncodingException e) {
            // shouldn't happen
            return null;
        }
    }

    private static String extractParameterValueFromUrl(String url, String paramName) {
        int queryStart = url.indexOf('?') >= 0 ? url.indexOf('?') : 0;
        int startPos = url.indexOf(paramName + "=", queryStart);
        if (startPos == -1) {
            return null;
        }
        int ampPos = url.indexOf("&", startPos);
        if (ampPos >= 0) {
            return url.substring(startPos + paramName.length() + 1, ampPos);
        }
        return url.substring(startPos + paramName.length() + 1);
    }

}