com.vmware.identity.samlservice.impl.RequestCacheImpl.java Source code

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Here is the source code for com.vmware.identity.samlservice.impl.RequestCacheImpl.java

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/*
 *  Copyright (c) 2012-2015 VMware, Inc.  All Rights Reserved.
 *
 *  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.vmware.identity.samlservice.impl;

import java.util.LinkedHashMap;

import org.apache.commons.lang.Validate;

import com.vmware.identity.samlservice.RequestCache;

/**
 * Singleton request cache implementation which allows
 *  - MAX_RETRIES for a single request
 *  - MAX_ENTRIES for a total number of requests being tracked
 *
 */
public class RequestCacheImpl extends LinkedHashMap<String, Integer> implements RequestCache {
    private static RequestCacheImpl singleton;

    // hide the constructor
    private RequestCacheImpl() {
    }

    private static final long serialVersionUID = 1L;
    private static final int MAX_RETRIES = 5; // maximum number of times we can process same SamlRequest (we allow for a few retries due to multi-step SPNEGO)
    private static final int MAX_ENTRIES = 1024; // maximum number of simultaneous requests to track (then eldest request will be removed from cache)

    /**
     * Return singleton instance of request cache
     * @return
     */
    public static RequestCacheImpl getRequestCache() {
        if (singleton == null) {
            singleton = new RequestCacheImpl();
        }
        return singleton;
    }

    /* (non-Javadoc)
     * @see com.vmware.identity.samlservice.RequestCache#shouldDenyRequest(java.lang.String)
     */
    public boolean shouldDenyRequest(String request) {
        boolean retval = false;

        if (this.containsKey(request)) {
            Integer retries = this.get(request);
            Validate.notNull(retries);
            if (retries >= MAX_RETRIES) {
                retval = true;
            }
        }
        return retval;
    }

    /* (non-Javadoc)
     * @see com.vmware.identity.samlservice.RequestCache#storeRequest(java.lang.String)
     */
    public void storeRequest(String request) {
        if (this.containsKey(request)) {
            Integer retries = this.get(request);
            Validate.notNull(retries);
            retries++;
            this.put(request, retries);
        } else {
            this.put(request, 1);
        }
    }

    /**
     * Query a request. Return true if the request can be found in the cache.
     * @param   request      The full quest string
     */
    public boolean isExistingRequest(String request) {
        if (this.containsKey(request)) {
            return true;
        } else {
            return false;
        }
    }

    @Override
    protected boolean removeEldestEntry(java.util.Map.Entry<String, Integer> eldest) {
        return this.size() > MAX_ENTRIES; // our strategy to keep cache size in check
    }
}