Consolidate BouncyCastle lookup/fallback logic to JcaTemplate

impl/src/main/java/io/jsonwebtoken/impl/lang/ConstantFunction.java

@@ -24,19 +24,12 @@
  */
 public final class ConstantFunction<T, R> implements Function<T, R> {
 
-    private static final Function<?, ?> NULL = new ConstantFunction<>(null);
-
     private final R value;
 
     public ConstantFunction(R value) {
         this.value = value;
     }
 
-    @SuppressWarnings("unchecked")
-    public static <T, R> Function<T, R> forNull() {
-        return (Function<T, R>) NULL;
-    }
-
     @Override
     public R apply(T t) {
         return this.value;

impl/src/main/java/io/jsonwebtoken/impl/lang/Functions.java

@@ -22,10 +22,6 @@ public final class Functions {
     private Functions() {
     }
 
-    public static <T, R> Function<T, R> forNull() {
-        return ConstantFunction.forNull();
-    }
-
     public static <T> Function<T, T> identity() {
         return new Function<T, T>() {
             @Override

impl/src/main/java/io/jsonwebtoken/impl/security/AesAlgorithm.java

@@ -16,8 +16,6 @@
 package io.jsonwebtoken.impl.security;
 
 import io.jsonwebtoken.impl.lang.Bytes;
-import io.jsonwebtoken.impl.lang.CheckedSupplier;
-import io.jsonwebtoken.impl.lang.Conditions;
 import io.jsonwebtoken.lang.Arrays;
 import io.jsonwebtoken.lang.Assert;
 import io.jsonwebtoken.security.AssociatedDataSupplier;
@@ -28,7 +26,6 @@
 import io.jsonwebtoken.security.SecretKeyBuilder;
 import io.jsonwebtoken.security.WeakKeyException;
 
-import javax.crypto.Cipher;
 import javax.crypto.SecretKey;
 import javax.crypto.spec.GCMParameterSpec;
 import javax.crypto.spec.IvParameterSpec;
@@ -62,17 +59,6 @@ abstract class AesAlgorithm extends CryptoAlgorithm implements KeyBuilderSupplie
         this.ivBitLength = jcaTransformation.equals("AESWrap") ? 0 : (this.gcm ? GCM_IV_SIZE : BLOCK_SIZE);
         // https://tools.ietf.org/html/rfc7518#section-5.2.3 through https://tools.ietf.org/html/rfc7518#section-5.3 :
         this.tagBitLength = this.gcm ? BLOCK_SIZE : this.keyBitLength;
-
-        // GCM mode only available on JDK 8 and later, so enable BC as a backup provider if necessary for <= JDK 7:
-        // TODO: remove when dropping JDK 7:
-        if (this.gcm) {
-            setProvider(Providers.findBouncyCastle(Conditions.notExists(new CheckedSupplier<Cipher>() {
-                @Override
-                public Cipher get() throws Exception {
-                    return Cipher.getInstance(jcaTransformation);
-                }
-            })));
-        }
     }
 
     @Override

impl/src/main/java/io/jsonwebtoken/impl/security/CryptoAlgorithm.java

@@ -35,8 +35,6 @@ abstract class CryptoAlgorithm implements Identifiable {
 
     private final String jcaName;
 
-    private Provider provider; // default, if any
-
     CryptoAlgorithm(String id, String jcaName) {
         Assert.hasText(id, "id cannot be null or empty.");
         this.ID = id;
@@ -53,27 +51,19 @@ String getJcaName() {
         return this.jcaName;
     }
 
-    protected void setProvider(Provider provider) { // can be null
-        this.provider = provider;
-    }
-
-    protected Provider getProvider() {
-        return this.provider;
-    }
-
     SecureRandom ensureSecureRandom(Request<?> request) {
         SecureRandom random = request != null ? request.getSecureRandom() : null;
         return random != null ? random : Randoms.secureRandom();
     }
 
     protected JcaTemplate jca() {
-        return new JcaTemplate(getJcaName(), getProvider());
+        return new JcaTemplate(getJcaName(), null);
     }
 
     protected JcaTemplate jca(Request<?> request) {
         Assert.notNull(request, "request cannot be null.");
         String jcaName = Assert.hasText(getJcaName(request), "Request jcaName cannot be null or empty.");
-        Provider provider = getProvider(request);
+        Provider provider = request.getProvider();
         SecureRandom random = ensureSecureRandom(request);
         return new JcaTemplate(jcaName, provider, random);
     }
@@ -82,18 +72,10 @@ protected String getJcaName(Request<?> request) {
         return getJcaName();
     }
 
-    protected Provider getProvider(Request<?> request) {
-        Provider provider = request.getProvider();
-        if (provider == null) {
-            provider = this.provider; // fallback, if any
-        }
-        return provider;
-    }
-
     protected SecretKey generateKey(KeyRequest<?> request) {
         AeadAlgorithm enc = Assert.notNull(request.getEncryptionAlgorithm(), "Request encryptionAlgorithm cannot be null.");
         SecretKeyBuilder builder = Assert.notNull(enc.key(), "Request encryptionAlgorithm KeyBuilder cannot be null.");
-        SecretKey key = builder.provider(getProvider(request)).random(request.getSecureRandom()).build();
+        SecretKey key = builder.provider(request.getProvider()).random(request.getSecureRandom()).build();
         return Assert.notNull(key, "Request encryptionAlgorithm SecretKeyBuilder cannot produce null keys.");
     }
 

impl/src/main/java/io/jsonwebtoken/impl/security/DefaultCurve.java

@@ -20,24 +20,15 @@
 import io.jsonwebtoken.security.Curve;
 import io.jsonwebtoken.security.KeyPairBuilder;
 
-import java.security.Provider;
-
 class DefaultCurve implements Curve {
 
     private final String ID;
 
     private final String JCA_NAME;
 
-    private final Provider PROVIDER; // can be null
-
     DefaultCurve(String id, String jcaName) {
-        this(id, jcaName, null);
-    }
-
-    DefaultCurve(String id, String jcaName, Provider provider) {
         this.ID = Assert.notNull(Strings.clean(id), "Curve ID cannot be null or empty.");
         this.JCA_NAME = Assert.notNull(Strings.clean(jcaName), "Curve jcaName cannot be null or empty.");
-        this.PROVIDER = provider;
     }
 
     @Override
@@ -49,10 +40,6 @@ public String getJcaName() {
         return this.JCA_NAME;
     }
 
-    public Provider getProvider() {
-        return this.PROVIDER;
-    }
-
     @Override
     public int hashCode() {
         return ID.hashCode();
@@ -76,6 +63,6 @@ public String toString() {
     }
 
     public KeyPairBuilder keyPair() {
-        return new DefaultKeyPairBuilder(this.JCA_NAME).provider(this.PROVIDER);
+        return new DefaultKeyPairBuilder(this.JCA_NAME);
     }
 }

impl/src/main/java/io/jsonwebtoken/impl/security/DefaultHashAlgorithm.java

@@ -22,7 +22,6 @@
 import io.jsonwebtoken.security.VerifyDigestRequest;
 
 import java.security.MessageDigest;
-import java.security.Provider;
 import java.util.Locale;
 
 public final class DefaultHashAlgorithm extends CryptoAlgorithm implements HashAlgorithm {
@@ -33,11 +32,6 @@ public final class DefaultHashAlgorithm extends CryptoAlgorithm implements HashA
         super(id, id.toUpperCase(Locale.ENGLISH));
     }
 
-    DefaultHashAlgorithm(String id, String jcaName, Provider provider) {
-        super(id, jcaName);
-        setProvider(provider);
-    }
-
     @Override
     public byte[] digest(final Request<byte[]> request) {
         Assert.notNull(request, "Request cannot be null.");

impl/src/main/java/io/jsonwebtoken/impl/security/EcSignatureAlgorithm.java

@@ -155,7 +155,6 @@ private EcSignatureAlgorithm(int orderBitLength, String oid) {
     @Override
     public KeyPairBuilder keyPair() {
         return new DefaultKeyPairBuilder(ECCurve.KEY_PAIR_GENERATOR_JCA_NAME, this.KEY_PAIR_GEN_PARAMS)
-                .provider(getProvider())
                 .random(Randoms.secureRandom());
     }