de.itsvs.cwtrpc.controller.PreparedCacheControlUriConfigBuilder.java Source code

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Here is the source code for de.itsvs.cwtrpc.controller.PreparedCacheControlUriConfigBuilder.java

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/*
 *  Copyright 2011 IT Services VS GmbH
 *
 *  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 de.itsvs.cwtrpc.controller;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * @author Volker Schmidt
 * @since 0.9
 */
public class PreparedCacheControlUriConfigBuilder {
    private final Log log = LogFactory.getLog(PreparedCacheControlUriConfigBuilder.class);

    public List<PreparedCacheControlUriConfig> build(List<CacheControlUriConfig> uriConfigs) {
        final List<PreparedCacheControlUriConfig> preparedUriConfigs;

        if (uriConfigs.isEmpty()) {
            return Collections.emptyList();
        }

        preparedUriConfigs = new ArrayList<PreparedCacheControlUriConfig>();
        for (CacheControlUriConfig uriConfig : uriConfigs) {
            preparedUriConfigs.add(build(uriConfig));
        }

        return preparedUriConfigs;
    }

    protected PreparedCacheControlUriConfig build(CacheControlUriConfig uriConfig) {
        final PreparedCacheControlUriConfig preparedUriConfig;

        preparedUriConfig = new PreparedCacheControlUriConfig(uriConfig.getValue(), uriConfig.getMethod(),
                buildCacheControlValue(uriConfig), getExpires(uriConfig), getPragmaNoCache(uriConfig));
        if (log.isDebugEnabled()) {
            log.debug("Prepared URI configuration for " + uriConfig + " is " + preparedUriConfig);
        }

        return preparedUriConfig;
    }

    protected String buildCacheControlValue(CacheControlUriConfig uriConfig) {
        final StringBuilder sb = new StringBuilder();

        if (uriConfig.isPublicContent()) {
            addCacheControlDirective(sb, "public");
        }
        if (uriConfig.isPrivateContent()) {
            addCacheControlDirective(sb, "private");
        }
        if (uriConfig.isNoCache()) {
            addCacheControlDirective(sb, "no-cache");
        }
        if (uriConfig.isNoStore()) {
            addCacheControlDirective(sb, "no-store");
        }
        if (uriConfig.isNoTransform()) {
            addCacheControlDirective(sb, "no-transform");
        }
        if (uriConfig.isMustRevalidate()) {
            addCacheControlDirective(sb, "must-revalidate");
        }
        if (uriConfig.isProxyRevalidate()) {
            addCacheControlDirective(sb, "proxy-revalidate");
        }
        if (uriConfig.getMaxAge() != null) {
            if (uriConfig.getMaxAge() < 0) {
                throw new IllegalArgumentException("'maxAge'must not be negative");
            }
            addCacheControlDirective(sb, "max-age=" + uriConfig.getMaxAge());
        }
        if (uriConfig.getSharedMaxage() != null) {
            if (uriConfig.getSharedMaxage() < 0) {
                throw new IllegalArgumentException("'s-maxage'must not be negative");
            }
            addCacheControlDirective(sb, "s-maxage=" + uriConfig.getSharedMaxage());
        }

        return ((sb.length() > 0) ? sb.toString() : null);
    }

    protected Integer getExpires(CacheControlUriConfig uriConfig) {
        if (uriConfig.getExpires() != null) {
            return uriConfig.getExpires();
        }

        /* use HTTP 1.1 max-age instead */
        return uriConfig.getMaxAge();
    }

    protected boolean getPragmaNoCache(CacheControlUriConfig uriConfig) {
        if (uriConfig.isPragmaNoCache()) {
            return true;
        }

        /* use HTTP 1.1 no-cache instead */
        return uriConfig.isNoCache();
    }

    protected StringBuilder addCacheControlDirective(StringBuilder sb, String directive) {
        if (sb.length() > 0) {
            sb.append(", ");
        }
        sb.append(directive);

        return sb;
    }
}