org.opensaml.xmlsec.encryption.support.ChainingEncryptedKeyResolver Maven / Gradle / Ivy
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* Licensed to the University Corporation for Advanced Internet Development,
* Inc. (UCAID) under one or more contributor license agreements. See the
* NOTICE file distributed with this work for additional information regarding
* copyright ownership. The UCAID 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.opensaml.xmlsec.encryption.support;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Set;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import net.shibboleth.utilities.java.support.annotation.constraint.NonnullElements;
import net.shibboleth.utilities.java.support.annotation.constraint.NotLive;
import net.shibboleth.utilities.java.support.annotation.constraint.Unmodifiable;
import net.shibboleth.utilities.java.support.logic.Constraint;
import org.opensaml.xmlsec.encryption.EncryptedData;
import org.opensaml.xmlsec.encryption.EncryptedKey;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.common.base.Predicates;
import com.google.common.collect.Collections2;
import com.google.common.collect.ImmutableList;
/**
* An implementation of {@link EncryptedKeyResolver} which chains multiple other resolver implementations together,
* calling them in the order specified in the resolver list.
*/
public class ChainingEncryptedKeyResolver extends AbstractEncryptedKeyResolver {
/** The list of resolvers which form the resolution chain. */
@Nonnull @NonnullElements private final List resolvers;
/** Class logger. */
@Nonnull private final Logger log = LoggerFactory.getLogger(ChainingEncryptedKeyResolver.class);
/**
* Constructor.
*
* @param encKeyResolvers the chain of encrypted key resolvers
*/
public ChainingEncryptedKeyResolver(@Nonnull final List encKeyResolvers) {
Constraint.isNotNull(encKeyResolvers, "List of EncryptedKeyResolvers cannot be null");
resolvers = new ArrayList<>(Collections2.filter(encKeyResolvers, Predicates.notNull()));
}
/**
* Constructor.
*
* @param encKeyResolvers the chain of encrypted key resolvers
* @param recipients the set of recipients
*/
public ChainingEncryptedKeyResolver(@Nonnull final List encKeyResolvers,
@Nullable final Set recipients) {
super(recipients);
Constraint.isNotNull(encKeyResolvers, "List of EncryptedKeyResolvers cannot be null");
resolvers = new ArrayList<>(Collections2.filter(encKeyResolvers, Predicates.notNull()));
}
/**
* Constructor.
*
* @param encKeyResolvers the chain of encrypted key resolvers
* @param recipient the recipient
*/
public ChainingEncryptedKeyResolver(@Nonnull final List encKeyResolvers,
@Nullable final String recipient) {
this(encKeyResolvers, Collections.singleton(recipient));
}
/**
* Get the unmodifiable list of resolvers which form the resolution chain.
*
* @return a list of EncryptedKeyResolver instances
*/
@Nonnull @NonnullElements @Unmodifiable @NotLive public List getResolverChain() {
return ImmutableList.copyOf(resolvers);
}
/** {@inheritDoc} */
@Override
@Nonnull public Iterable resolve(@Nonnull final EncryptedData encryptedData) {
if (resolvers.isEmpty()) {
log.warn("Chaining encrypted key resolver resolution was attempted with an empty resolver chain");
throw new IllegalStateException("The resolver chain is empty");
}
return new ChainingIterable(this, encryptedData);
}
/**
* Implementation of {@link Iterable} to be returned by {@link ChainingEncryptedKeyResolver}.
*/
public class ChainingIterable implements Iterable {
/** The chaining encrypted key resolver which owns this instance. */
private final ChainingEncryptedKeyResolver parent;
/** The EncryptedData context for resolution. */
private final EncryptedData encryptedData;
/**
* Constructor.
*
* @param resolver the ChainingEncryptedKeyResolver parent
* @param encData the EncryptedData context for resolution
*/
public ChainingIterable(@Nonnull final ChainingEncryptedKeyResolver resolver,
@Nonnull final EncryptedData encData) {
parent = resolver;
encryptedData = encData;
}
/** {@inheritDoc} */
@Nonnull public Iterator iterator() {
return new ChainingIterator(parent, encryptedData);
}
}
/**
* Implementation of {@link Iterator} to be (indirectly) returned by {@link ChainingEncryptedKeyResolver}.
*
*/
public class ChainingIterator implements Iterator {
/** Class logger. */
private final Logger log = LoggerFactory.getLogger(ChainingEncryptedKeyResolver.ChainingIterator.class);
/** The chaining encrypted key resolver which owns this instance. */
private final ChainingEncryptedKeyResolver parent;
/** The EncryptedData context for resolution. */
private final EncryptedData encryptedData;
/** The iterator over resolvers in the chain. */
private final Iterator resolverIterator;
/** The iterator over EncryptedKey instances from the current resolver. */
private Iterator keyIterator;
/** The current resolver which is returning encrypted keys. */
private EncryptedKeyResolver currentResolver;
/** The next encrypted key that is safe to return. */
private EncryptedKey nextKey;
/**
* Constructor.
*
* @param resolver the ChainingEncryptedKeyResolver parent
* @param encData the EncryptedData context for resolution
*/
public ChainingIterator(@Nonnull final ChainingEncryptedKeyResolver resolver,
@Nonnull final EncryptedData encData) {
parent = resolver;
encryptedData = encData;
resolverIterator = parent.getResolverChain().iterator();
keyIterator = getNextKeyIterator();
nextKey = null;
}
/** {@inheritDoc} */
@Override
public boolean hasNext() {
if (nextKey != null) {
return true;
}
nextKey = getNextKey();
if (nextKey != null) {
return true;
}
return false;
}
/** {@inheritDoc} */
@Override
public EncryptedKey next() {
EncryptedKey tempKey;
if (nextKey != null) {
tempKey = nextKey;
nextKey = null;
return tempKey;
}
tempKey = getNextKey();
if (tempKey != null) {
return tempKey;
} else {
throw new NoSuchElementException("No more EncryptedKey elements are available");
}
}
/** {@inheritDoc} */
@Override
public void remove() {
throw new UnsupportedOperationException("Remove operation is not supported by this iterator");
}
/**
* Get the iterator from the next resolver in the chain.
*
* @return an iterator of encrypted keys, or null if none remain
*/
@Nullable private Iterator getNextKeyIterator() {
if (resolverIterator.hasNext()) {
currentResolver = resolverIterator.next();
log.debug("Getting key iterator from next resolver: {}", currentResolver.getClass().toString());
return currentResolver.resolve(encryptedData).iterator();
} else {
log.debug("No more resolvers available in the resolver chain");
currentResolver = null;
return null;
}
}
/**
* Get the next encrypted key that will be returned by this iterator.
*
* @return the next encrypted key to return, or null if none remain
*/
@Nullable private EncryptedKey getNextKey() {
EncryptedKey tempKey;
if (keyIterator != null) {
while (keyIterator.hasNext()) {
tempKey = keyIterator.next();
if (parent.matchRecipient(tempKey.getRecipient())) {
log.debug("Found matching encrypted key: {}", tempKey.toString());
return tempKey;
}
}
}
keyIterator = getNextKeyIterator();
while (keyIterator != null) {
while (keyIterator.hasNext()) {
tempKey = keyIterator.next();
if (parent.matchRecipient(tempKey.getRecipient())) {
log.debug("Found matching encrypted key: {}", tempKey.toString());
return tempKey;
}
}
keyIterator = getNextKeyIterator();
}
return null;
}
}
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