external-sop: Mark methods with @Nonnull where applicable

external-sop/src/main/java/sop/external/ExternalSOP.java

@@ -106,76 +106,91 @@ public class ExternalSOP implements SOP {
     }
 
     @Override
+    @Nonnull
     public Version version() {
         return new VersionExternal(binaryName, properties);
     }
 
     @Override
+    @Nonnull
     public GenerateKey generateKey() {
         return new GenerateKeyExternal(binaryName, properties);
     }
 
     @Override
+    @Nonnull
     public ExtractCert extractCert() {
         return new ExtractCertExternal(binaryName, properties);
     }
 
     @Override
+    @Nonnull
     public DetachedSign detachedSign() {
         return new DetachedSignExternal(binaryName, properties, tempDirProvider);
     }
 
     @Override
+    @Nonnull
     public InlineSign inlineSign() {
         return new InlineSignExternal(binaryName, properties);
     }
 
     @Override
+    @Nonnull
     public DetachedVerify detachedVerify() {
         return new DetachedVerifyExternal(binaryName, properties);
     }
 
     @Override
+    @Nonnull
     public InlineVerify inlineVerify() {
         return new InlineVerifyExternal(binaryName, properties, tempDirProvider);
     }
 
     @Override
+    @Nonnull
     public InlineDetach inlineDetach() {
         return new InlineDetachExternal(binaryName, properties, tempDirProvider);
     }
 
     @Override
+    @Nonnull
     public Encrypt encrypt() {
         return new EncryptExternal(binaryName, properties, tempDirProvider);
     }
 
     @Override
+    @Nonnull
     public Decrypt decrypt() {
         return new DecryptExternal(binaryName, properties, tempDirProvider);
     }
 
     @Override
+    @Nonnull
     public Armor armor() {
         return new ArmorExternal(binaryName, properties);
     }
 
     @Override
+    @Nonnull
     public ListProfiles listProfiles() {
         return new ListProfilesExternal(binaryName, properties);
     }
 
     @Override
+    @Nonnull
     public RevokeKey revokeKey() {
         return new RevokeKeyExternal(binaryName, properties);
     }
 
     @Override
+    @Nonnull
     public ChangeKeyPassword changeKeyPassword() {
         return new ChangeKeyPasswordExternal(binaryName, properties);
     }
 
     @Override
+    @Nonnull
     public Dearmor dearmor() {
         return new DearmorExternal(binaryName, properties);
     }
@@ -349,7 +364,7 @@ public class ExternalSOP implements SOP {
 
             return new Ready() {
                 @Override
-                public void writeTo(OutputStream outputStream) throws IOException {
+                public void writeTo(@Nonnull OutputStream outputStream) throws IOException {
                     byte[] buf = new byte[4096];
                     int r;
                     while ((r = stdIn.read(buf)) >= 0) {
@@ -388,7 +403,7 @@ public class ExternalSOP implements SOP {
 
             return new Ready() {
                 @Override
-                public void writeTo(OutputStream outputStream) throws IOException {
+                public void writeTo(@Nonnull OutputStream outputStream) throws IOException {
                     byte[] buf = new byte[4096];
                     int r;
                     while ((r = standardIn.read(buf)) > 0) {

external-sop/src/main/java/sop/external/operation/ArmorExternal.java

@@ -10,6 +10,7 @@ import sop.exception.SOPGPException;
 import sop.external.ExternalSOP;
 import sop.operation.Armor;
 
+import javax.annotation.Nonnull;
 import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.List;
@@ -30,13 +31,16 @@ public class ArmorExternal implements Armor {
     }
 
     @Override
-    public Armor label(ArmorLabel label) throws SOPGPException.UnsupportedOption {
+    @Deprecated
+    @Nonnull
+    public Armor label(@Nonnull ArmorLabel label) throws SOPGPException.UnsupportedOption {
         commandList.add("--label=" + label);
         return this;
     }
 
     @Override
-    public Ready data(InputStream data) throws SOPGPException.BadData {
+    @Nonnull
+    public Ready data(@Nonnull InputStream data) throws SOPGPException.BadData {
         return ExternalSOP.executeTransformingOperation(Runtime.getRuntime(), commandList, envList, data);
     }
 }

external-sop/src/main/java/sop/external/operation/ChangeKeyPasswordExternal.java

@@ -9,6 +9,7 @@ import sop.exception.SOPGPException;
 import sop.external.ExternalSOP;
 import sop.operation.ChangeKeyPassword;
 
+import javax.annotation.Nonnull;
 import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.List;
@@ -27,13 +28,15 @@ public class ChangeKeyPasswordExternal implements ChangeKeyPassword {
     }
 
     @Override
+    @Nonnull
     public ChangeKeyPassword noArmor() {
         this.commandList.add("--no-armor");
         return this;
     }
 
     @Override
-    public ChangeKeyPassword oldKeyPassphrase(String oldPassphrase) {
+    @Nonnull
+    public ChangeKeyPassword oldKeyPassphrase(@Nonnull String oldPassphrase) {
         this.commandList.add("--old-key-password=@ENV:KEY_PASSWORD_" + keyPasswordCounter);
         this.envList.add("KEY_PASSWORD_" + keyPasswordCounter + "=" + oldPassphrase);
         keyPasswordCounter++;
@@ -42,7 +45,8 @@ public class ChangeKeyPasswordExternal implements ChangeKeyPassword {
     }
 
     @Override
-    public ChangeKeyPassword newKeyPassphrase(String newPassphrase) {
+    @Nonnull
+    public ChangeKeyPassword newKeyPassphrase(@Nonnull String newPassphrase) {
         this.commandList.add("--new-key-password=@ENV:KEY_PASSWORD_" + keyPasswordCounter);
         this.envList.add("KEY_PASSWORD_" + keyPasswordCounter + "=" + newPassphrase);
         keyPasswordCounter++;
@@ -51,7 +55,8 @@ public class ChangeKeyPasswordExternal implements ChangeKeyPassword {
     }
 
     @Override
-    public Ready keys(InputStream inputStream) throws SOPGPException.KeyIsProtected, SOPGPException.BadData {
+    @Nonnull
+    public Ready keys(@Nonnull InputStream inputStream) throws SOPGPException.KeyIsProtected, SOPGPException.BadData {
         return ExternalSOP.executeTransformingOperation(Runtime.getRuntime(), commandList, envList, inputStream);
     }
 }

external-sop/src/main/java/sop/external/operation/DearmorExternal.java

@@ -9,6 +9,7 @@ import sop.exception.SOPGPException;
 import sop.external.ExternalSOP;
 import sop.operation.Dearmor;
 
+import javax.annotation.Nonnull;
 import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.List;
@@ -29,7 +30,8 @@ public class DearmorExternal implements Dearmor {
     }
 
     @Override
-    public Ready data(InputStream data) throws SOPGPException.BadData {
+    @Nonnull
+    public Ready data(@Nonnull InputStream data) throws SOPGPException.BadData {
         return ExternalSOP.executeTransformingOperation(Runtime.getRuntime(), commandList, envList, data);
     }
 }

external-sop/src/main/java/sop/external/operation/DecryptExternal.java

@@ -13,6 +13,7 @@ import sop.external.ExternalSOP;
 import sop.operation.Decrypt;
 import sop.util.UTCUtil;
 
+import javax.annotation.Nonnull;
 import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileInputStream;
@@ -48,21 +49,24 @@ public class DecryptExternal implements Decrypt {
     }
 
     @Override
-    public Decrypt verifyNotBefore(Date timestamp)
+    @Nonnull
+    public Decrypt verifyNotBefore(@Nonnull Date timestamp)
             throws SOPGPException.UnsupportedOption {
         this.commandList.add("--verify-not-before=" + UTCUtil.formatUTCDate(timestamp));
         return this;
     }
 
     @Override
-    public Decrypt verifyNotAfter(Date timestamp)
+    @Nonnull
+    public Decrypt verifyNotAfter(@Nonnull Date timestamp)
             throws SOPGPException.UnsupportedOption {
         this.commandList.add("--verify-not-after=" + UTCUtil.formatUTCDate(timestamp));
         return this;
     }
 
     @Override
-    public Decrypt verifyWithCert(InputStream cert)
+    @Nonnull
+    public Decrypt verifyWithCert(@Nonnull InputStream cert)
             throws SOPGPException.BadData, SOPGPException.UnsupportedAsymmetricAlgo, IOException {
         String envVar = "VERIFY_WITH_" + verifyWithCounter++;
         commandList.add("--verify-with=@ENV:" + envVar);
@@ -71,7 +75,8 @@ public class DecryptExternal implements Decrypt {
     }
 
     @Override
-    public Decrypt withSessionKey(SessionKey sessionKey)
+    @Nonnull
+    public Decrypt withSessionKey(@Nonnull SessionKey sessionKey)
             throws SOPGPException.UnsupportedOption {
         String envVar = "SESSION_KEY_" + withSessionKeyCounter++;
         commandList.add("--with-session-key=@ENV:" + envVar);
@@ -80,7 +85,8 @@ public class DecryptExternal implements Decrypt {
     }
 
     @Override
-    public Decrypt withPassword(String password)
+    @Nonnull
+    public Decrypt withPassword(@Nonnull String password)
             throws SOPGPException.PasswordNotHumanReadable, SOPGPException.UnsupportedOption {
         String envVar = "PASSWORD_" + withPasswordCounter++;
         commandList.add("--with-password=@ENV:" + envVar);
@@ -89,7 +95,8 @@ public class DecryptExternal implements Decrypt {
     }
 
     @Override
-    public Decrypt withKey(InputStream key)
+    @Nonnull
+    public Decrypt withKey(@Nonnull InputStream key)
             throws SOPGPException.BadData, SOPGPException.UnsupportedAsymmetricAlgo, IOException {
         String envVar = "KEY_" + keyCounter++;
         commandList.add("@ENV:" + envVar);
@@ -98,7 +105,8 @@ public class DecryptExternal implements Decrypt {
     }
 
     @Override
-    public Decrypt withKeyPassword(byte[] password)
+    @Nonnull
+    public Decrypt withKeyPassword(@Nonnull byte[] password)
             throws SOPGPException.UnsupportedOption, SOPGPException.PasswordNotHumanReadable {
         String envVar = "KEY_PASSWORD_" + withKeyPasswordCounter++;
         commandList.add("--with-key-password=@ENV:" + envVar);
@@ -107,7 +115,8 @@ public class DecryptExternal implements Decrypt {
     }
 
     @Override
-    public ReadyWithResult<DecryptionResult> ciphertext(InputStream ciphertext)
+    @Nonnull
+    public ReadyWithResult<DecryptionResult> ciphertext(@Nonnull InputStream ciphertext)
             throws SOPGPException.BadData, SOPGPException.MissingArg, SOPGPException.CannotDecrypt,
             SOPGPException.KeyIsProtected, IOException {
         File tempDir = tempDirProvider.provideTempDirectory();
@@ -131,7 +140,7 @@ public class DecryptExternal implements Decrypt {
 
             return new ReadyWithResult<DecryptionResult>() {
                 @Override
-                public DecryptionResult writeTo(OutputStream outputStream) throws IOException {
+                public DecryptionResult writeTo(@Nonnull OutputStream outputStream) throws IOException {
                     byte[] buf = new byte[4096];
                     int r;
                     while ((r = ciphertext.read(buf)) > 0) {

external-sop/src/main/java/sop/external/operation/DetachedSignExternal.java

@@ -12,6 +12,7 @@ import sop.exception.SOPGPException;
 import sop.external.ExternalSOP;
 import sop.operation.DetachedSign;
 
+import javax.annotation.Nonnull;
 import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileInputStream;
@@ -43,13 +44,15 @@ public class DetachedSignExternal implements DetachedSign {
     }
 
     @Override
+    @Nonnull
     public DetachedSign noArmor() {
         commandList.add("--no-armor");
         return this;
     }
 
     @Override
-    public DetachedSign key(InputStream key) throws SOPGPException.KeyCannotSign, SOPGPException.BadData, SOPGPException.UnsupportedAsymmetricAlgo, IOException {
+    @Nonnull
+    public DetachedSign key(@Nonnull InputStream key) throws SOPGPException.KeyCannotSign, SOPGPException.BadData, SOPGPException.UnsupportedAsymmetricAlgo, IOException {
         String envVar = "KEY_" + keyCounter++;
         commandList.add("@ENV:" + envVar);
         envList.add(envVar + "=" + ExternalSOP.readString(key));
@@ -57,7 +60,8 @@ public class DetachedSignExternal implements DetachedSign {
     }
 
     @Override
-    public DetachedSign withKeyPassword(byte[] password) throws SOPGPException.UnsupportedOption, SOPGPException.PasswordNotHumanReadable {
+    @Nonnull
+    public DetachedSign withKeyPassword(@Nonnull byte[] password) throws SOPGPException.UnsupportedOption, SOPGPException.PasswordNotHumanReadable {
         String envVar = "WITH_KEY_PASSWORD_" + withKeyPasswordCounter++;
         commandList.add("--with-key-password=@ENV:" + envVar);
         envList.add(envVar + "=" + new String(password));
@@ -65,13 +69,15 @@ public class DetachedSignExternal implements DetachedSign {
     }
 
     @Override
-    public DetachedSign mode(SignAs mode) throws SOPGPException.UnsupportedOption {
+    @Nonnull
+    public DetachedSign mode(@Nonnull SignAs mode) throws SOPGPException.UnsupportedOption {
         commandList.add("--as=" + mode);
         return this;
     }
 
     @Override
-    public ReadyWithResult<SigningResult> data(InputStream data)
+    @Nonnull
+    public ReadyWithResult<SigningResult> data(@Nonnull InputStream data)
             throws IOException, SOPGPException.KeyIsProtected, SOPGPException.ExpectedText {
 
         File tempDir = tempDirProvider.provideTempDirectory();
@@ -88,7 +94,7 @@ public class DetachedSignExternal implements DetachedSign {
 
             return new ReadyWithResult<SigningResult>() {
                 @Override
-                public SigningResult writeTo(OutputStream outputStream) throws IOException {
+                public SigningResult writeTo(@Nonnull OutputStream outputStream) throws IOException {
                     byte[] buf = new byte[4096];
                     int r;
                     while ((r = data.read(buf)) > 0) {

external-sop/src/main/java/sop/external/operation/DetachedVerifyExternal.java

@@ -11,6 +11,7 @@ import sop.operation.DetachedVerify;
 import sop.operation.VerifySignatures;
 import sop.util.UTCUtil;
 
+import javax.annotation.Nonnull;
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStream;
@@ -42,31 +43,36 @@ public class DetachedVerifyExternal implements DetachedVerify {
     }
 
     @Override
-    public DetachedVerify notBefore(Date timestamp) throws SOPGPException.UnsupportedOption {
+    @Nonnull
+    public DetachedVerify notBefore(@Nonnull Date timestamp) throws SOPGPException.UnsupportedOption {
         commandList.add("--not-before=" + UTCUtil.formatUTCDate(timestamp));
         return this;
     }
 
     @Override
-    public DetachedVerify notAfter(Date timestamp) throws SOPGPException.UnsupportedOption {
+    @Nonnull
+    public DetachedVerify notAfter(@Nonnull Date timestamp) throws SOPGPException.UnsupportedOption {
         commandList.add("--not-after=" + UTCUtil.formatUTCDate(timestamp));
         return this;
     }
 
     @Override
-    public DetachedVerify cert(InputStream cert) throws SOPGPException.BadData {
+    @Nonnull
+    public DetachedVerify cert(@Nonnull InputStream cert) throws SOPGPException.BadData {
         this.certs.add(cert);
         return this;
     }
 
     @Override
-    public VerifySignatures signatures(InputStream signatures) throws SOPGPException.BadData {
+    @Nonnull
+    public VerifySignatures signatures(@Nonnull InputStream signatures) throws SOPGPException.BadData {
         this.signatures = signatures;
         return this;
     }
 
     @Override
-    public List<Verification> data(InputStream data) throws IOException, SOPGPException.NoSignature, SOPGPException.BadData {
+    @Nonnull
+    public List<Verification> data(@Nonnull InputStream data) throws IOException, SOPGPException.NoSignature, SOPGPException.BadData {
         commandList.add("@ENV:SIGNATURE");
         envList.add("SIGNATURE=" + ExternalSOP.readString(signatures));
 

external-sop/src/main/java/sop/external/operation/EncryptExternal.java

@@ -12,6 +12,7 @@ import sop.exception.SOPGPException;
 import sop.external.ExternalSOP;
 import sop.operation.Encrypt;
 
+import javax.annotation.Nonnull;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
@@ -42,20 +43,23 @@ public class EncryptExternal implements Encrypt {
     }
 
     @Override
+    @Nonnull
     public Encrypt noArmor() {
         this.commandList.add("--no-armor");
         return this;
     }
 
     @Override
-    public Encrypt mode(EncryptAs mode)
+    @Nonnull
+    public Encrypt mode(@Nonnull EncryptAs mode)
             throws SOPGPException.UnsupportedOption {
         this.commandList.add("--as=" + mode);
         return this;
     }
 
     @Override
-    public Encrypt signWith(InputStream key)
+    @Nonnull
+    public Encrypt signWith(@Nonnull InputStream key)
             throws SOPGPException.KeyCannotSign, SOPGPException.UnsupportedAsymmetricAlgo, SOPGPException.BadData,
             IOException {
         String envVar = "SIGN_WITH_" + SIGN_WITH_COUNTER++;
@@ -65,7 +69,8 @@ public class EncryptExternal implements Encrypt {
     }
 
     @Override
-    public Encrypt withKeyPassword(byte[] password)
+    @Nonnull
+    public Encrypt withKeyPassword(@Nonnull byte[] password)
             throws SOPGPException.PasswordNotHumanReadable, SOPGPException.UnsupportedOption {
         String envVar = "KEY_PASSWORD_" + KEY_PASSWORD_COUNTER++;
         commandList.add("--with-key-password=@ENV:" + envVar);
@@ -74,7 +79,8 @@ public class EncryptExternal implements Encrypt {
     }
 
     @Override
-    public Encrypt withPassword(String password)
+    @Nonnull
+    public Encrypt withPassword(@Nonnull String password)
             throws SOPGPException.PasswordNotHumanReadable, SOPGPException.UnsupportedOption {
         String envVar = "PASSWORD_" + PASSWORD_COUNTER++;
         commandList.add("--with-password=@ENV:" + envVar);
@@ -83,7 +89,8 @@ public class EncryptExternal implements Encrypt {
     }
 
     @Override
-    public Encrypt withCert(InputStream cert)
+    @Nonnull
+    public Encrypt withCert(@Nonnull InputStream cert)
             throws SOPGPException.CertCannotEncrypt, SOPGPException.UnsupportedAsymmetricAlgo, SOPGPException.BadData,
             IOException {
         String envVar = "CERT_" + CERT_COUNTER++;
@@ -93,13 +100,15 @@ public class EncryptExternal implements Encrypt {
     }
 
     @Override
-    public Encrypt profile(String profileName) {
+    @Nonnull
+    public Encrypt profile(@Nonnull String profileName) {
         commandList.add("--profile=" + profileName);
         return this;
     }
 
     @Override
-    public ReadyWithResult<EncryptionResult> plaintext(InputStream plaintext)
+    @Nonnull
+    public ReadyWithResult<EncryptionResult> plaintext(@Nonnull InputStream plaintext)
             throws SOPGPException.KeyIsProtected, IOException {
         File tempDir = tempDirProvider.provideTempDirectory();
 
@@ -116,7 +125,7 @@ public class EncryptExternal implements Encrypt {
 
             return new ReadyWithResult<EncryptionResult>() {
                 @Override
-                public EncryptionResult writeTo(OutputStream outputStream) throws IOException {
+                public EncryptionResult writeTo(@Nonnull OutputStream outputStream) throws IOException {
                     byte[] buf = new byte[4096];
                     int r;
                     while ((r = plaintext.read(buf)) > 0) {

external-sop/src/main/java/sop/external/operation/ExtractCertExternal.java

@@ -9,6 +9,7 @@ import sop.exception.SOPGPException;
 import sop.external.ExternalSOP;
 import sop.operation.ExtractCert;
 
+import javax.annotation.Nonnull;
 import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.List;
@@ -29,13 +30,15 @@ public class ExtractCertExternal implements ExtractCert {
     }
 
     @Override
+    @Nonnull
     public ExtractCert noArmor() {
         this.commandList.add("--no-armor");
         return this;
     }
 
     @Override
-    public Ready key(InputStream keyInputStream) throws SOPGPException.BadData {
+    @Nonnull
+    public Ready key(@Nonnull InputStream keyInputStream) throws SOPGPException.BadData {
         return ExternalSOP.executeTransformingOperation(Runtime.getRuntime(), commandList, envList, keyInputStream);
     }
 }

external-sop/src/main/java/sop/external/operation/GenerateKeyExternal.java

@@ -9,6 +9,7 @@ import sop.exception.SOPGPException;
 import sop.external.ExternalSOP;
 import sop.operation.GenerateKey;
 
+import javax.annotation.Nonnull;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Properties;
@@ -30,19 +31,22 @@ public class GenerateKeyExternal implements GenerateKey {
     }
 
     @Override
+    @Nonnull
     public GenerateKey noArmor() {
         this.commandList.add("--no-armor");
         return this;
     }
 
     @Override
-    public GenerateKey userId(String userId) {
+    @Nonnull
+    public GenerateKey userId(@Nonnull String userId) {
         this.commandList.add(userId);
         return this;
     }
 
     @Override
-    public GenerateKey withKeyPassword(String password)
+    @Nonnull
+    public GenerateKey withKeyPassword(@Nonnull String password)
             throws SOPGPException.PasswordNotHumanReadable, SOPGPException.UnsupportedOption {
         this.commandList.add("--with-key-password=@ENV:KEY_PASSWORD_" + keyPasswordCounter);
         this.envList.add("KEY_PASSWORD_" + keyPasswordCounter + "=" + password);
@@ -52,18 +56,21 @@ public class GenerateKeyExternal implements GenerateKey {
     }
 
     @Override
-    public GenerateKey profile(String profile) {
+    @Nonnull
+    public GenerateKey profile(@Nonnull String profile) {
         commandList.add("--profile=" + profile);
         return this;
     }
 
     @Override
+    @Nonnull
     public GenerateKey signingOnly() {
         commandList.add("--signing-only");
         return this;
     }
 
     @Override
+    @Nonnull
     public Ready generate()
             throws SOPGPException.MissingArg, SOPGPException.UnsupportedAsymmetricAlgo {
         return ExternalSOP.executeProducingOperation(Runtime.getRuntime(), commandList, envList);

external-sop/src/main/java/sop/external/operation/InlineDetachExternal.java

@@ -10,6 +10,7 @@ import sop.exception.SOPGPException;
 import sop.external.ExternalSOP;
 import sop.operation.InlineDetach;
 
+import javax.annotation.Nonnull;
 import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
@@ -37,13 +38,15 @@ public class InlineDetachExternal implements InlineDetach {
     }
 
     @Override
+    @Nonnull
     public InlineDetach noArmor() {
         commandList.add("--no-armor");
         return this;
     }
 
     @Override
-    public ReadyWithResult<Signatures> message(InputStream messageInputStream) throws IOException, SOPGPException.BadData {
+    @Nonnull
+    public ReadyWithResult<Signatures> message(@Nonnull InputStream messageInputStream) throws IOException, SOPGPException.BadData {
         File tempDir = tempDirProvider.provideTempDirectory();
 
         File signaturesOut = new File(tempDir, "signatures");
@@ -60,7 +63,7 @@ public class InlineDetachExternal implements InlineDetach {
 
             return new ReadyWithResult<Signatures>() {
                 @Override
-                public Signatures writeTo(OutputStream outputStream) throws IOException {
+                public Signatures writeTo(@Nonnull OutputStream outputStream) throws IOException {
                     byte[] buf = new byte[4096];
                     int r;
                     while ((r = messageInputStream.read(buf)) > 0) {
@@ -90,7 +93,7 @@ public class InlineDetachExternal implements InlineDetach {
                     final byte[] sigBytes = signaturesBuffer.toByteArray();
                     return new Signatures() {
                         @Override
-                        public void writeTo(OutputStream signatureOutputStream) throws IOException {
+                        public void writeTo(@Nonnull OutputStream signatureOutputStream) throws IOException {
                             signatureOutputStream.write(sigBytes);
                         }
                     };

external-sop/src/main/java/sop/external/operation/InlineSignExternal.java

@@ -10,6 +10,7 @@ import sop.exception.SOPGPException;
 import sop.external.ExternalSOP;
 import sop.operation.InlineSign;
 
+import javax.annotation.Nonnull;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
@@ -34,13 +35,15 @@ public class InlineSignExternal implements InlineSign {
     }
 
     @Override
+    @Nonnull
     public InlineSign noArmor() {
         commandList.add("--no-armor");
         return this;
     }
 
     @Override
-    public InlineSign key(InputStream key) throws SOPGPException.KeyCannotSign, SOPGPException.BadData, SOPGPException.UnsupportedAsymmetricAlgo, IOException {
+    @Nonnull
+    public InlineSign key(@Nonnull InputStream key) throws SOPGPException.KeyCannotSign, SOPGPException.BadData, SOPGPException.UnsupportedAsymmetricAlgo, IOException {
         String envVar = "KEY_" + keyCounter++;
         commandList.add("@ENV:" + envVar);
         envList.add(envVar + "=" + ExternalSOP.readString(key));
@@ -48,7 +51,8 @@ public class InlineSignExternal implements InlineSign {
     }
 
     @Override
-    public InlineSign withKeyPassword(byte[] password) throws SOPGPException.UnsupportedOption, SOPGPException.PasswordNotHumanReadable {
+    @Nonnull
+    public InlineSign withKeyPassword(@Nonnull byte[] password) throws SOPGPException.UnsupportedOption, SOPGPException.PasswordNotHumanReadable {
         String envVar = "WITH_KEY_PASSWORD_" + withKeyPasswordCounter++;
         commandList.add("--with-key-password=@ENV:" + envVar);
         envList.add(envVar + "=" + new String(password));
@@ -56,13 +60,15 @@ public class InlineSignExternal implements InlineSign {
     }
 
     @Override
-    public InlineSign mode(InlineSignAs mode) throws SOPGPException.UnsupportedOption {
+    @Nonnull
+    public InlineSign mode(@Nonnull InlineSignAs mode) throws SOPGPException.UnsupportedOption {
         commandList.add("--as=" + mode);
         return this;
     }
 
     @Override
-    public Ready data(InputStream data) throws SOPGPException.KeyIsProtected, SOPGPException.ExpectedText {
+    @Nonnull
+    public Ready data(@Nonnull InputStream data) throws SOPGPException.KeyIsProtected, SOPGPException.ExpectedText {
         return ExternalSOP.executeTransformingOperation(Runtime.getRuntime(), commandList, envList, data);
     }
 }

external-sop/src/main/java/sop/external/operation/InlineVerifyExternal.java

@@ -11,6 +11,7 @@ import sop.external.ExternalSOP;
 import sop.operation.InlineVerify;
 import sop.util.UTCUtil;
 
+import javax.annotation.Nonnull;
 import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileInputStream;
@@ -42,19 +43,22 @@ public class InlineVerifyExternal implements InlineVerify {
     }
 
     @Override
-    public InlineVerify notBefore(Date timestamp) throws SOPGPException.UnsupportedOption {
+    @Nonnull
+    public InlineVerify notBefore(@Nonnull Date timestamp) throws SOPGPException.UnsupportedOption {
         commandList.add("--not-before=" + UTCUtil.formatUTCDate(timestamp));
         return this;
     }
 
     @Override
-    public InlineVerify notAfter(Date timestamp) throws SOPGPException.UnsupportedOption {
+    @Nonnull
+    public InlineVerify notAfter(@Nonnull Date timestamp) throws SOPGPException.UnsupportedOption {
         commandList.add("--not-after=" + UTCUtil.formatUTCDate(timestamp));
         return this;
     }
 
     @Override
-    public InlineVerify cert(InputStream cert) throws SOPGPException.BadData, IOException {
+    @Nonnull
+    public InlineVerify cert(@Nonnull InputStream cert) throws SOPGPException.BadData, IOException {
         String envVar = "CERT_" + certCounter++;
         commandList.add("@ENV:" + envVar);
         envList.add(envVar + "=" + ExternalSOP.readString(cert));
@@ -62,7 +66,8 @@ public class InlineVerifyExternal implements InlineVerify {
     }
 
     @Override
-    public ReadyWithResult<List<Verification>> data(InputStream data) throws IOException, SOPGPException.NoSignature, SOPGPException.BadData {
+    @Nonnull
+    public ReadyWithResult<List<Verification>> data(@Nonnull InputStream data) throws IOException, SOPGPException.NoSignature, SOPGPException.BadData {
         File tempDir = tempDirProvider.provideTempDirectory();
 
         File verificationsOut = new File(tempDir, "verifications-out");
@@ -79,7 +84,7 @@ public class InlineVerifyExternal implements InlineVerify {
 
             return new ReadyWithResult<List<Verification>>() {
                 @Override
-                public List<Verification> writeTo(OutputStream outputStream) throws IOException, SOPGPException.NoSignature {
+                public List<Verification> writeTo(@Nonnull OutputStream outputStream) throws IOException, SOPGPException.NoSignature {
                     byte[] buf = new byte[4096];
                     int r;
                     while ((r = data.read(buf)) > 0) {

external-sop/src/main/java/sop/external/operation/ListProfilesExternal.java

@@ -8,6 +8,7 @@ import sop.Profile;
 import sop.external.ExternalSOP;
 import sop.operation.ListProfiles;
 
+import javax.annotation.Nonnull;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
@@ -25,7 +26,8 @@ public class ListProfilesExternal implements ListProfiles {
     }
 
     @Override
-    public List<Profile> subcommand(String command) {
+    @Nonnull
+    public List<Profile> subcommand(@Nonnull String command) {
         commandList.add(command);
         try {
             String output = new String(ExternalSOP.executeProducingOperation(Runtime.getRuntime(), commandList, envList).getBytes());

external-sop/src/main/java/sop/external/operation/RevokeKeyExternal.java

@@ -9,6 +9,7 @@ import sop.exception.SOPGPException;
 import sop.external.ExternalSOP;
 import sop.operation.RevokeKey;
 
+import javax.annotation.Nonnull;
 import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.List;
@@ -28,13 +29,15 @@ public class RevokeKeyExternal implements RevokeKey {
     }
 
     @Override
+    @Nonnull
     public RevokeKey noArmor() {
         this.commandList.add("--no-armor");
         return this;
     }
 
     @Override
-    public RevokeKey withKeyPassword(byte[] password) throws SOPGPException.UnsupportedOption, SOPGPException.PasswordNotHumanReadable {
+    @Nonnull
+    public RevokeKey withKeyPassword(@Nonnull byte[] password) throws SOPGPException.UnsupportedOption, SOPGPException.PasswordNotHumanReadable {
         String envVar = "KEY_PASSWORD_" + withKeyPasswordCounter++;
         commandList.add("--with-key-password=@ENV:" + envVar);
         envList.add(envVar + "=" + new String(password));
@@ -42,7 +45,8 @@ public class RevokeKeyExternal implements RevokeKey {
     }
 
     @Override
-    public Ready keys(InputStream keys) {
+    @Nonnull
+    public Ready keys(@Nonnull InputStream keys) {
         return ExternalSOP.executeTransformingOperation(Runtime.getRuntime(), commandList, envList, keys);
     }
 }

external-sop/src/main/java/sop/external/operation/VersionExternal.java

@@ -7,6 +7,7 @@ package sop.external.operation;
 import sop.external.ExternalSOP;
 import sop.operation.Version;
 
+import javax.annotation.Nonnull;
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
@@ -27,6 +28,7 @@ public class VersionExternal implements Version {
     }
 
     @Override
+    @Nonnull
     public String getName() {
         String[] command = new String[] {binary, "version"};
         String[] env = ExternalSOP.propertiesToEnv(environment).toArray(new String[0]);
@@ -45,6 +47,7 @@ public class VersionExternal implements Version {
     }
 
     @Override
+    @Nonnull
     public String getVersion() {
         String[] command = new String[] {binary, "version"};
         String[] env = ExternalSOP.propertiesToEnv(environment).toArray(new String[0]);
@@ -63,6 +66,7 @@ public class VersionExternal implements Version {
     }
 
     @Override
+    @Nonnull
     public String getBackendVersion() {
         String[] command = new String[] {binary, "version", "--backend"};
         String[] env = ExternalSOP.propertiesToEnv(environment).toArray(new String[0]);
@@ -82,6 +86,7 @@ public class VersionExternal implements Version {
     }
 
     @Override
+    @Nonnull
     public String getExtendedVersion() {
         String[] command = new String[] {binary, "version", "--extended"};
         String[] env = ExternalSOP.propertiesToEnv(environment).toArray(new String[0]);
@@ -137,6 +142,7 @@ public class VersionExternal implements Version {
     }
 
     @Override
+    @Nonnull
     public String getSopSpecVersion() {
         String[] command = new String[] {binary, "version", "--sop-spec"};
         String[] env = ExternalSOP.propertiesToEnv(environment).toArray(new String[0]);