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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).

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/*
 * 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.keyprovider;

import java.io.IOException;
import java.security.GeneralSecurityException;
import java.security.KeyPair;
import java.util.Iterator;
import java.util.NoSuchElementException;

import org.apache.sshd.common.session.SessionContext;
import org.apache.sshd.common.session.SessionContextHolder;

/**
 * Iterates over several {@link KeyIdentityProvider}-s exhausting their keys one by one (lazily).
 *
 * @author Apache MINA SSHD Project
 */
public class MultiKeyIdentityIterator implements Iterator, SessionContextHolder {
    protected Iterator currentProvider;
    protected boolean finished;
    private final SessionContext sessionContext;
    private final Iterator providers;

    public MultiKeyIdentityIterator(SessionContext session, Iterable providers) {
        this.providers = (providers == null) ? null : providers.iterator();
        this.sessionContext = session;
    }

    public Iterator getProviders() {
        return providers;
    }

    @Override
    public SessionContext getSessionContext() {
        return sessionContext;
    }

    @Override
    public boolean hasNext() {
        if (finished) {
            return false;
        }

        Iterator provs = getProviders();
        if (provs == null) {
            finished = true;
            return false;
        }

        if ((currentProvider != null) && currentProvider.hasNext()) {
            return true;
        }

        SessionContext session = getSessionContext();
        while (provs.hasNext()) {
            KeyIdentityProvider p = provs.next();
            Iterable keys;
            try {
                keys = (p == null) ? null : p.loadKeys(session);
            } catch (IOException | GeneralSecurityException e) {
                throw new IllegalArgumentException("Unexpected " + e.getClass().getSimpleName() + ")"
                                                   + " keys loading exception: " + e.getMessage(),
                        e);
            }
            currentProvider = (keys == null) ? null : keys.iterator();

            if ((currentProvider != null) && currentProvider.hasNext()) {
                return true;
            }
        }

        // exhausted all providers
        finished = false;
        return false;
    }

    @Override
    public KeyPair next() {
        if (finished) {
            throw new NoSuchElementException("All identities have been exhausted");
        }

        if (currentProvider == null) {
            throw new IllegalStateException("'next()' called without asking 'hasNext()'");
        }

        return currentProvider.next();
    }
}