#162: Collapsed interfaces, added helper methods to get rid of casts.

parsingdata · May 26, 2017 · 30df29e · 30df29e
1 parent 51187b3
commit 30df29e
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Showing 11 changed files with 66 additions and 99 deletions.
diff --git a/core/src/main/java/io/parsingdata/metal/FinalTrampoline.java b/core/src/main/java/io/parsingdata/metal/FinalTrampoline.java
diff --git a/core/src/main/java/io/parsingdata/metal/IntermediateTrampoline.java b/core/src/main/java/io/parsingdata/metal/IntermediateTrampoline.java
diff --git a/core/src/main/java/io/parsingdata/metal/Trampoline.java b/core/src/main/java/io/parsingdata/metal/Trampoline.java
@@ -26,10 +26,28 @@ public interface Trampoline<T> {
 
     default T computeResult() throws IOException {
         Trampoline<T> current = this;
-        while(current.hasNext()) {
+        while (current.hasNext()) {
             current = current.next();
         }
         return current.result();
     }
 
+    static <T> Trampoline<T> complete(CompletedTrampoline<T> completedTrampoline) { return completedTrampoline; }
+
+    interface CompletedTrampoline<T> extends Trampoline<T> {
+
+        default boolean hasNext() { return false; }
+        default Trampoline<T> next() { throw new UnsupportedOperationException("A CompletedTrampoline does not have a next computation."); }
+
+    }
+
+    static <T> Trampoline<T> intermediate(IntermediateTrampoline<T> intermediateTrampoline) { return intermediateTrampoline; }
+
+    interface IntermediateTrampoline<T> extends Trampoline<T> {
+
+        default T result() { throw new UnsupportedOperationException("An IntermediateTrampoline does not have a result."); }
+        default boolean hasNext() { return true; }
+
+    }
+
 }
diff --git a/core/src/main/java/io/parsingdata/metal/token/Cho.java b/core/src/main/java/io/parsingdata/metal/token/Cho.java
@@ -16,22 +16,21 @@
 
 package io.parsingdata.metal.token;
 
+import static io.parsingdata.metal.Trampoline.complete;
+import static io.parsingdata.metal.Trampoline.intermediate;
 import static io.parsingdata.metal.Util.checkContainsNoNulls;
-import static io.parsingdata.metal.Util.failure;
 import static io.parsingdata.metal.Util.success;
 import static io.parsingdata.metal.data.ImmutableList.create;
 
 import java.io.IOException;
 import java.util.Objects;
 import java.util.Optional;
 
+import io.parsingdata.metal.Trampoline;
 import io.parsingdata.metal.Util;
 import io.parsingdata.metal.data.Environment;
 import io.parsingdata.metal.data.ImmutableList;
 import io.parsingdata.metal.encoding.Encoding;
-import io.parsingdata.metal.FinalTrampoline;
-import io.parsingdata.metal.IntermediateTrampoline;
-import io.parsingdata.metal.Trampoline;
 
 /**
  * A {@link Token} that specifies a choice out of a list of tokens.
@@ -57,13 +56,13 @@ protected Optional<Environment> parseImpl(final String scope, final Environment
 
     private Trampoline<Optional<Environment>> iterate(final String scope, final Optional<Environment> environment, final Encoding encoding, final ImmutableList<Token> list) throws IOException {
         if (list.isEmpty()) {
-            return (FinalTrampoline<Optional<Environment>>) Util::failure;
+            return complete(Util::failure);
         }
         final Optional<Environment> result = list.head.parse(scope, environment.get(), encoding);
         if (result.isPresent()) {
-            return (FinalTrampoline<Optional<Environment>>) () -> success(result.get().closeBranch());
+            return complete(() -> success(result.get().closeBranch()));
         }
-        return (IntermediateTrampoline<Optional<Environment>>) () -> iterate(scope, environment, encoding, list.tail);
+        return intermediate(() -> iterate(scope, environment, encoding, list.tail));
     }
 
     @Override

diff --git a/core/src/main/java/io/parsingdata/metal/token/Rep.java b/core/src/main/java/io/parsingdata/metal/token/Rep.java
@@ -16,18 +16,18 @@
 
 package io.parsingdata.metal.token;
 
+import static io.parsingdata.metal.Trampoline.complete;
+import static io.parsingdata.metal.Trampoline.intermediate;
 import static io.parsingdata.metal.Util.checkNotNull;
 import static io.parsingdata.metal.Util.success;
 
 import java.io.IOException;
 import java.util.Objects;
 import java.util.Optional;
 
+import io.parsingdata.metal.Trampoline;
 import io.parsingdata.metal.data.Environment;
 import io.parsingdata.metal.encoding.Encoding;
-import io.parsingdata.metal.FinalTrampoline;
-import io.parsingdata.metal.IntermediateTrampoline;
-import io.parsingdata.metal.Trampoline;
 
 /**
  * A {@link Token} that specifies a possible repetition of a token.
@@ -55,9 +55,9 @@ protected Optional<Environment> parseImpl(final String scope, final Environment
 
     private Trampoline<Optional<Environment>> iterate(final String scope, final Optional<Environment> environment, final Encoding encoding, final Environment previous) throws IOException {
         if (environment.isPresent()) {
-            return (IntermediateTrampoline<Optional<Environment>>) () -> iterate(scope, token.parse(scope, environment.get(), encoding), encoding, environment.get());
+            return intermediate(() -> iterate(scope, token.parse(scope, environment.get(), encoding), encoding, environment.get()));
         }
-        return (FinalTrampoline<Optional<Environment>>) () -> success(previous.closeBranch());
+        return complete(() -> success(previous.closeBranch()));
     }
 
     @Override

diff --git a/core/src/main/java/io/parsingdata/metal/token/RepN.java b/core/src/main/java/io/parsingdata/metal/token/RepN.java
@@ -16,6 +16,8 @@
 
 package io.parsingdata.metal.token;
 
+import static io.parsingdata.metal.Trampoline.complete;
+import static io.parsingdata.metal.Trampoline.intermediate;
 import static io.parsingdata.metal.Util.checkNotNull;
 import static io.parsingdata.metal.Util.failure;
 import static io.parsingdata.metal.Util.success;
@@ -24,15 +26,13 @@
 import java.util.Objects;
 import java.util.Optional;
 
+import io.parsingdata.metal.Trampoline;
 import io.parsingdata.metal.Util;
 import io.parsingdata.metal.data.Environment;
 import io.parsingdata.metal.data.ImmutableList;
 import io.parsingdata.metal.encoding.Encoding;
 import io.parsingdata.metal.expression.value.Value;
 import io.parsingdata.metal.expression.value.ValueExpression;
-import io.parsingdata.metal.FinalTrampoline;
-import io.parsingdata.metal.IntermediateTrampoline;
-import io.parsingdata.metal.Trampoline;
 
 /**
  * A {@link Token} that specifies a bounded repetition of a token.
@@ -68,12 +68,12 @@ protected Optional<Environment> parseImpl(final String scope, final Environment
 
     private Trampoline<Optional<Environment>> iterate(final String scope, final Optional<Environment> environment, final Encoding encoding, final long count) throws IOException {
         if (!environment.isPresent()) {
-            return (FinalTrampoline<Optional<Environment>>) Util::failure;
+            return complete(Util::failure);
         }
         if (count <= 0) {
-            return (FinalTrampoline<Optional<Environment>>) () -> success(environment.get().closeBranch());
+            return complete(() -> success(environment.get().closeBranch()));
         }
-        return (IntermediateTrampoline<Optional<Environment>>) () -> iterate(scope, token.parse(scope, environment.get(), encoding), encoding, count - 1);
+        return intermediate(() -> iterate(scope, token.parse(scope, environment.get(), encoding), encoding, count - 1));
     }
 
     @Override

diff --git a/core/src/main/java/io/parsingdata/metal/token/Seq.java b/core/src/main/java/io/parsingdata/metal/token/Seq.java
@@ -16,22 +16,21 @@
 
 package io.parsingdata.metal.token;
 
+import static io.parsingdata.metal.Trampoline.complete;
+import static io.parsingdata.metal.Trampoline.intermediate;
 import static io.parsingdata.metal.Util.checkContainsNoNulls;
-import static io.parsingdata.metal.Util.failure;
 import static io.parsingdata.metal.Util.success;
 import static io.parsingdata.metal.data.ImmutableList.create;
 
 import java.io.IOException;
 import java.util.Objects;
 import java.util.Optional;
 
+import io.parsingdata.metal.Trampoline;
 import io.parsingdata.metal.Util;
 import io.parsingdata.metal.data.Environment;
 import io.parsingdata.metal.data.ImmutableList;
 import io.parsingdata.metal.encoding.Encoding;
-import io.parsingdata.metal.FinalTrampoline;
-import io.parsingdata.metal.IntermediateTrampoline;
-import io.parsingdata.metal.Trampoline;
 
 /**
  * A {@link Token} that specifies a dependency between a list of tokens.
@@ -57,12 +56,12 @@ protected Optional<Environment> parseImpl(final String scope, final Environment
 
     private Trampoline<Optional<Environment>> iterate(final String scope, final Optional<Environment> environment, final Encoding encoding, final ImmutableList<Token> list) throws IOException {
         if (!environment.isPresent()) {
-            return (FinalTrampoline<Optional<Environment>>) Util::failure;
+            return complete(Util::failure);
         }
         if (list.isEmpty()) {
-            return (FinalTrampoline<Optional<Environment>>) () -> success(environment.get().closeBranch());
+            return complete(() -> success(environment.get().closeBranch()));
         }
-        return (IntermediateTrampoline<Optional<Environment>>) () -> iterate(scope, list.head.parse(scope, environment.get(), encoding), encoding, list.tail);
+        return intermediate(() -> iterate(scope, list.head.parse(scope, environment.get(), encoding), encoding, list.tail));
     }
 
     @Override

diff --git a/core/src/main/java/io/parsingdata/metal/token/Sub.java b/core/src/main/java/io/parsingdata/metal/token/Sub.java
@@ -16,6 +16,8 @@
 
 package io.parsingdata.metal.token;
 
+import static io.parsingdata.metal.Trampoline.complete;
+import static io.parsingdata.metal.Trampoline.intermediate;
 import static io.parsingdata.metal.Util.checkNotNull;
 import static io.parsingdata.metal.Util.failure;
 import static io.parsingdata.metal.Util.success;
@@ -25,6 +27,7 @@
 import java.util.Objects;
 import java.util.Optional;
 
+import io.parsingdata.metal.Trampoline;
 import io.parsingdata.metal.Util;
 import io.parsingdata.metal.data.Environment;
 import io.parsingdata.metal.data.ImmutableList;
@@ -33,9 +36,6 @@
 import io.parsingdata.metal.encoding.Encoding;
 import io.parsingdata.metal.expression.value.Value;
 import io.parsingdata.metal.expression.value.ValueExpression;
-import io.parsingdata.metal.FinalTrampoline;
-import io.parsingdata.metal.IntermediateTrampoline;
-import io.parsingdata.metal.Trampoline;
 
 /**
  * A {@link Token} that specifies a token to be parsed at a specific location
@@ -73,14 +73,14 @@ protected Optional<Environment> parseImpl(final String scope, final Environment
 
     private Trampoline<Optional<Environment>> iterate(final String scope, final ImmutableList<Optional<Value>> addresses, final long returnOffset, final Environment environment, final Encoding encoding) throws IOException {
         if (!addresses.head.isPresent()) {
-            return (FinalTrampoline<Optional<Environment>>) Util::failure;
+            return complete(Util::failure);
         }
         final Optional<Environment> result = parse(scope, addresses.head.get().asNumeric().longValue(), environment.source, environment, encoding);
         if (result.isPresent()) {
-            if (addresses.tail.isEmpty()) { return (FinalTrampoline<Optional<Environment>>) () -> success(result.get().closeBranch().seek(returnOffset)); }
-            return (IntermediateTrampoline<Optional<Environment>>) () -> iterate(scope, addresses.tail, returnOffset, result.get(), encoding);
+            if (addresses.tail.isEmpty()) { return complete(() -> success(result.get().closeBranch().seek(returnOffset))); }
+            return intermediate(() -> iterate(scope, addresses.tail, returnOffset, result.get(), encoding));
         }
-        return (FinalTrampoline<Optional<Environment>>) Util::failure;
+        return complete(Util::failure);
     }
 
     private Optional<Environment> parse(final String scope, final long offset, final Source source, final Environment environment, final Encoding encoding) throws IOException {

diff --git a/core/src/main/java/io/parsingdata/metal/token/Tie.java b/core/src/main/java/io/parsingdata/metal/token/Tie.java
@@ -16,6 +16,8 @@
 
 package io.parsingdata.metal.token;
 
+import static io.parsingdata.metal.Trampoline.complete;
+import static io.parsingdata.metal.Trampoline.intermediate;
 import static io.parsingdata.metal.Util.checkNotNull;
 import static io.parsingdata.metal.Util.failure;
 import static io.parsingdata.metal.Util.success;
@@ -24,15 +26,13 @@
 import java.util.Objects;
 import java.util.Optional;
 
+import io.parsingdata.metal.Trampoline;
 import io.parsingdata.metal.Util;
 import io.parsingdata.metal.data.Environment;
 import io.parsingdata.metal.data.ImmutableList;
 import io.parsingdata.metal.encoding.Encoding;
 import io.parsingdata.metal.expression.value.Value;
 import io.parsingdata.metal.expression.value.ValueExpression;
-import io.parsingdata.metal.FinalTrampoline;
-import io.parsingdata.metal.IntermediateTrampoline;
-import io.parsingdata.metal.Trampoline;
 
 /**
  * A {@link Token} that specifies a token to be parsed inside the result of a
@@ -70,14 +70,14 @@ protected Optional<Environment> parseImpl(final String scope, final Environment
 
     private Trampoline<Optional<Environment>> iterate(final String scope, final ImmutableList<Optional<Value>> values, final int index, final Environment returnEnvironment, final Environment environment, final Encoding encoding) throws IOException {
         if (!values.head.isPresent()) {
-            return (FinalTrampoline<Optional<Environment>>) Util::failure;
+            return complete(Util::failure);
         }
         final Optional<Environment> result = token.parse(scope, environment.source(dataExpression, index, environment, encoding), encoding);
         if (result.isPresent()) {
-            if (values.tail.isEmpty()) { return (FinalTrampoline<Optional<Environment>>) () -> success(new Environment(result.get().closeBranch().order, returnEnvironment.source, returnEnvironment.offset, returnEnvironment.callbacks)); }
-            return (IntermediateTrampoline<Optional<Environment>>) () -> iterate(scope, values.tail, index + 1, returnEnvironment, result.get(), encoding);
+            if (values.tail.isEmpty()) { return complete(() -> success(new Environment(result.get().closeBranch().order, returnEnvironment.source, returnEnvironment.offset, returnEnvironment.callbacks))); }
+            return intermediate(() -> iterate(scope, values.tail, index + 1, returnEnvironment, result.get(), encoding));
         }
-        return (FinalTrampoline<Optional<Environment>>) Util::failure;
+        return complete(Util::failure);
     }
 
     @Override

diff --git a/core/src/main/java/io/parsingdata/metal/token/While.java b/core/src/main/java/io/parsingdata/metal/token/While.java
@@ -17,21 +17,20 @@
 package io.parsingdata.metal.token;
 
 import static io.parsingdata.metal.Shorthand.expTrue;
+import static io.parsingdata.metal.Trampoline.complete;
+import static io.parsingdata.metal.Trampoline.intermediate;
 import static io.parsingdata.metal.Util.checkNotNull;
-import static io.parsingdata.metal.Util.failure;
 import static io.parsingdata.metal.Util.success;
 
 import java.io.IOException;
 import java.util.Objects;
 import java.util.Optional;
 
+import io.parsingdata.metal.Trampoline;
 import io.parsingdata.metal.Util;
 import io.parsingdata.metal.data.Environment;
 import io.parsingdata.metal.encoding.Encoding;
 import io.parsingdata.metal.expression.Expression;
-import io.parsingdata.metal.FinalTrampoline;
-import io.parsingdata.metal.IntermediateTrampoline;
-import io.parsingdata.metal.Trampoline;
 
 /**
  * A {@link Token} that specifies a conditional repetition of a token.
@@ -64,12 +63,12 @@ protected Optional<Environment> parseImpl(final String scope, final Environment
 
     private Trampoline<Optional<Environment>> iterate(final String scope, final Optional<Environment> environment, final Encoding encoding) {
         if (!environment.isPresent()) {
-            return (FinalTrampoline<Optional<Environment>>) Util::failure;
+            return complete(Util::failure);
         }
         if (predicate.eval(environment.get().order, encoding)) {
-            return (IntermediateTrampoline<Optional<Environment>>) () -> iterate(scope, token.parse(scope, environment.get(), encoding), encoding);
+            return intermediate(() -> iterate(scope, token.parse(scope, environment.get(), encoding), encoding));
         }
-        return (FinalTrampoline<Optional<Environment>>) () -> success(environment.get().closeBranch());
+        return complete(() -> success(environment.get().closeBranch()));
     }
 
     @Override

diff --git a/core/src/test/java/io/parsingdata/metal/token/util/TrampolineTest.java b/core/src/test/java/io/parsingdata/metal/token/util/TrampolineTest.java
@@ -20,8 +20,8 @@
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
 
-import io.parsingdata.metal.FinalTrampoline;
-import io.parsingdata.metal.IntermediateTrampoline;
+import io.parsingdata.metal.Trampoline.CompletedTrampoline;
+import io.parsingdata.metal.Trampoline.IntermediateTrampoline;
 
 public class TrampolineTest {
 
@@ -38,8 +38,8 @@ public void resultOnIntermediateTrampoline() {
     @Test
     public void nextOnFinalTrampoline() {
         thrown.expect(UnsupportedOperationException.class);
-        thrown.expectMessage("A FinalTrampoline does not have a next computation.");
-        ((FinalTrampoline<Integer>) () -> 42).next();
+        thrown.expectMessage("A CompletedTrampoline does not have a next computation.");
+        ((CompletedTrampoline<Integer>) () -> 42).next();
     }
 
 }