/*
 * Copyright 2010 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.security.authentication.jaas.memory;

import java.util.Collections;
import java.util.Map;

import javax.security.auth.login.AppConfigurationEntry;
import javax.security.auth.login.Configuration;

import org.springframework.util.Assert;

/**
 * <p>
 * An in memory representation of a JAAS configuration. The constructor accepts
 * a Map where the key represents the name of the login context name and the
 * value is an Array of {@link AppConfigurationEntry} for that login context
 * name. A default Array of {@link AppConfigurationEntry}s can be specified
 * which will be returned if a login context is specified which is undefined.
 * </p>
 * 
 * @author Rob Winch
 */
public class InMemoryConfiguration extends Configuration {
    //~ Instance fields ================================================================================================

    private final AppConfigurationEntry[] defaultConfiguration;
    private final Map<String, AppConfigurationEntry[]> mappedConfigurations;

    //~ Constructors ===================================================================================================

    /**
     * Creates a new instance with only a defaultConfiguration. Any
     * configuration name will result in defaultConfiguration being returned.
     * 
     * @param defaultConfiguration
     *            The result for any calls to
     *            {@link #getAppConfigurationEntry(String)}. Can be
     *            <code>null</code>.
     */
    public InMemoryConfiguration(AppConfigurationEntry[] defaultConfiguration) {
        this(Collections.<String, AppConfigurationEntry[]> emptyMap(), defaultConfiguration);
    }

    /**
     * Creates a new instance with a mapping of login context name to an array
     * of {@link AppConfigurationEntry}s.
     * 
     * @param mappedConfigurations
     *            each key represents a login context name and each value is an
     *            Array of {@link AppConfigurationEntry}s that should be used.
     */
    public InMemoryConfiguration(Map<String, AppConfigurationEntry[]> mappedConfigurations) {
        this(mappedConfigurations, null);
    }

    /**
     * Creates a new instance with a mapping of login context name to an array
     * of {@link AppConfigurationEntry}s along with a default configuration that
     * will be used if no mapping is found for the given login context name.
     * 
     * @param mappedConfigurations
     *            each key represents a login context name and each value is an
     *            Array of {@link AppConfigurationEntry}s that should be used.
     * @param defaultConfiguration The result for any calls to
     *            {@link #getAppConfigurationEntry(String)}. Can be
     *            <code>null</code>.
     */
    public InMemoryConfiguration(Map<String, AppConfigurationEntry[]> mappedConfigurations,
            AppConfigurationEntry[] defaultConfiguration) {
        Assert.notNull(mappedConfigurations, "mappedConfigurations cannot be null.");
        this.mappedConfigurations = mappedConfigurations;
        this.defaultConfiguration = defaultConfiguration;
    }

    //~ Methods ========================================================================================================

    @Override
    public AppConfigurationEntry[] getAppConfigurationEntry(String name) {
        AppConfigurationEntry[] mappedResult = mappedConfigurations.get(name);
        return mappedResult == null ? defaultConfiguration : mappedResult;
    }

    /**
     * Does nothing, but required for JDK5
     */
    public void refresh() {
    }
}