org.apache.sshd.common.AttributeRepository Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of wildfly-client-all

This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

There is a newer version: 34.0.0.Final

Show newest version

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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.apache.sshd.common;

import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Map;
import java.util.Objects;

import org.apache.sshd.common.util.MapEntryUtils;

/**
 * @author Apache MINA SSHD Project
 */
public interface AttributeRepository {
    /**
     * 
     * Type safe key for storage of user attributes. Typically it is used as a static variable that is shared between
     * the producer and the consumer. To further restrict access the setting or getting it from the store one can add
     * static {@code get/set methods} e.g:
     * 
     *
     *      * 
     * public static final AttributeKey<MyValue> MY_KEY = new AttributeKey<MyValue>();
     *
     * public static MyValue getMyValue(Session s) {
     *   return s.getAttribute(MY_KEY);
     * }
     *
     * public static void setMyValue(Session s, MyValue value) {
     *   s.setAttribute(MY_KEY, value);
     * }
     * 
     * 
     *
     * @param   type of value stored in the attribute.
     * @author     Apache MINA SSHD Project
     */
    // CHECKSTYLE:OFF
    class AttributeKey {
        public AttributeKey() {
            super();
        }
    }
    // CHECKSTYLE:ON

    /**
     * @return Current number of user-defined attributes stored in the repository
     */
    int getAttributesCount();

    /**
     * Returns the value of the user-defined attribute.
     *
     * @param   The generic attribute type
     * @param  key The key of the attribute; must not be {@code null}.
     * @return     {@code null} if there is no value associated with the specified key
     */
     T getAttribute(AttributeKey key);

    /**
     * Attempts to resolve the associated value by going up the store's hierarchy (if any)
     *
     * @param   The generic attribute type
     * @param  key The key of the attribute; must not be {@code null}.
     * @return     {@code null} if there is no value associated with the specified key either in this repository or any
     *             of its ancestors (if any available)
     */
    default  T resolveAttribute(AttributeKey key) {
        return getAttribute(key);
    }

    /**
     * @return A {@link Collection} snapshot of all the currently registered attributes in the repository
     */
    Collection> attributeKeys();

    static  AttributeRepository ofKeyValuePair(AttributeKey key, A value) {
        Objects.requireNonNull(key, "No key provided");
        Objects.requireNonNull(value, "No value provided");
        return ofAttributesMap(Collections.singletonMap(key, value));
    }

    static AttributeRepository ofAttributesMap(Map, ?> attributes) {
        return new AttributeRepository() {
            @Override
            public int getAttributesCount() {
                return attributes.size();
            }

            @Override
            @SuppressWarnings("unchecked")
            public  T getAttribute(AttributeKey key) {
                Objects.requireNonNull(key, "No key provided");
                return MapEntryUtils.isEmpty(attributes) ? null : (T) attributes.get(key);
            }

            @Override
            public Collection> attributeKeys() {
                return MapEntryUtils.isEmpty(attributes)
                        ? Collections.emptySet()
                        : new HashSet<>(attributes.keySet());
            }

            @Override
            public String toString() {
                return AttributeRepository.class.getSimpleName() + "[" + attributes + "]";
            }
        };
    }
}

Related Artifacts