com.amazonaws.encryptionsdk.internal.LazyMessageCryptoHandler Maven / Gradle / Ivy
package com.amazonaws.encryptionsdk.internal;
import com.amazonaws.encryptionsdk.MasterKey;
import com.amazonaws.encryptionsdk.model.CiphertextHeaders;
import java.util.List;
import java.util.Map;
import java.util.function.Function;
import javax.annotation.concurrent.NotThreadSafe;
/**
* A {@link MessageCryptoHandler} that delegates to another MessageCryptoHandler, which is created
* at the last possible moment. Typically, this is used in order to defer the creation of the data
* key (and associated request to the {@link com.amazonaws.encryptionsdk.CryptoMaterialsManager}
* until the max message size is known.
*/
@NotThreadSafe
public class LazyMessageCryptoHandler implements MessageCryptoHandler {
private Function delegateFactory;
private MessageCryptoHandler delegate;
private long maxInputSize = -1;
public static final class LateBoundInfo {
private final long maxInputSize;
private LateBoundInfo(long maxInputSize) {
this.maxInputSize = maxInputSize;
}
public long getMaxInputSize() {
return maxInputSize;
}
}
public LazyMessageCryptoHandler(Function delegateFactory) {
this.delegateFactory = delegateFactory;
this.delegate = null;
}
private MessageCryptoHandler getDelegate() {
if (delegate == null) {
delegate = delegateFactory.apply(new LateBoundInfo(maxInputSize));
if (maxInputSize != -1) {
delegate.setMaxInputLength(maxInputSize);
}
// Release references to the delegate factory, now that we're done with it.
delegateFactory = null;
}
return delegate;
}
@Override
public void setMaxInputLength(long size) {
if (size < 0) {
throw new IllegalArgumentException("Max input size must be non-negative");
}
if (delegate == null) {
if (maxInputSize == -1 || maxInputSize > size) {
maxInputSize = size;
}
} else {
delegate.setMaxInputLength(size);
}
}
@Override
public boolean isComplete() {
// If we haven't generated the delegate, we're definitely not done yet.
return delegate != null && delegate.isComplete();
}
/* Operations which autovivify the delegate */
@Override
public Map getEncryptionContext() {
return getDelegate().getEncryptionContext();
}
@Override
public CiphertextHeaders getHeaders() {
return getDelegate().getHeaders();
}
@Override
public ProcessingSummary processBytes(byte[] in, int inOff, int inLen, byte[] out, int outOff) {
return getDelegate().processBytes(in, inOff, inLen, out, outOff);
}
@Override
public List> getMasterKeys() {
return getDelegate().getMasterKeys();
}
@Override
public int doFinal(byte[] out, int outOff) {
return getDelegate().doFinal(out, outOff);
}
@Override
public int estimateOutputSize(int inLen) {
return getDelegate().estimateOutputSize(inLen);
}
@Override
public int estimatePartialOutputSize(int inLen) {
return getDelegate().estimatePartialOutputSize(inLen);
}
@Override
public int estimateFinalOutputSize() {
return getDelegate().estimateFinalOutputSize();
}
}