1 files changed, 220 insertions, 0 deletions
diff --git a/gson/src/main/java/com/google/gson/internal/ConstructorConstructor.java b/gson/src/main/java/com/google/gson/internal/ConstructorConstructor.java
new file mode 100644
index 00000000..62bae91c
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+++ b/gson/src/main/java/com/google/gson/internal/ConstructorConstructor.java
@@ -0,0 +1,220 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ *
+ * Licensed 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 com.google.gson.internal;
+
+import com.google.gson.InstanceCreator;
+import com.google.gson.JsonIOException;
+import com.google.gson.reflect.TypeToken;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.ParameterizedType;
+import java.lang.reflect.Type;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.EnumSet;
+import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
+import java.util.LinkedList;
+import java.util.Map;
+import java.util.Queue;
+import java.util.Set;
+import java.util.SortedMap;
+import java.util.SortedSet;
+import java.util.TreeMap;
+import java.util.TreeSet;
+
+/**
+ * Returns a function that can construct an instance of a requested type.
+ */
+public final class ConstructorConstructor {
+  private final Map<Type, InstanceCreator<?>> instanceCreators;
+
+  public ConstructorConstructor(Map<Type, InstanceCreator<?>> instanceCreators) {
+    this.instanceCreators = instanceCreators;
+  }
+
+  public <T> ObjectConstructor<T> get(TypeToken<T> typeToken) {
+    final Type type = typeToken.getType();
+    final Class<? super T> rawType = typeToken.getRawType();
+
+    // first try an instance creator
+
+    @SuppressWarnings("unchecked") // types must agree
+    final InstanceCreator<T> typeCreator = (InstanceCreator<T>) instanceCreators.get(type);
+    if (typeCreator != null) {
+      return new ObjectConstructor<T>() {
+        public T construct() {
+          return typeCreator.createInstance(type);
+        }
+      };
+    }
+
+    // Next try raw type match for instance creators
+    @SuppressWarnings("unchecked") // types must agree
+    final InstanceCreator<T> rawTypeCreator =
+        (InstanceCreator<T>) instanceCreators.get(rawType);
+    if (rawTypeCreator != null) {
+      return new ObjectConstructor<T>() {
+        public T construct() {
+          return rawTypeCreator.createInstance(type);
+        }
+      };
+    }
+
+    ObjectConstructor<T> defaultConstructor = newDefaultConstructor(rawType);
+    if (defaultConstructor != null) {
+      return defaultConstructor;
+    }
+
+    ObjectConstructor<T> defaultImplementation = newDefaultImplementationConstructor(type, rawType);
+    if (defaultImplementation != null) {
+      return defaultImplementation;
+    }
+
+    // finally try unsafe
+    return newUnsafeAllocator(type, rawType);
+  }
+
+  private <T> ObjectConstructor<T> newDefaultConstructor(Class<? super T> rawType) {
+    try {
+      final Constructor<? super T> constructor = rawType.getDeclaredConstructor();
+      if (!constructor.isAccessible()) {
+        constructor.setAccessible(true);
+      }
+      return new ObjectConstructor<T>() {
+        @SuppressWarnings("unchecked") // T is the same raw type as is requested
+        public T construct() {
+          try {
+            Object[] args = null;
+            return (T) constructor.newInstance(args);
+          } catch (InstantiationException e) {
+            // TODO: JsonParseException ?
+            throw new RuntimeException("Failed to invoke " + constructor + " with no args", e);
+          } catch (InvocationTargetException e) {
+            // TODO: don't wrap if cause is unchecked!
+            // TODO: JsonParseException ?
+            throw new RuntimeException("Failed to invoke " + constructor + " with no args",
+                e.getTargetException());
+          } catch (IllegalAccessException e) {
+            throw new AssertionError(e);
+          }
+        }
+      };
+    } catch (NoSuchMethodException e) {
+      return null;
+    }
+  }
+
+  /**
+   * Constructors for common interface types like Map and List and their
+   * subtypes.
+   */
+  @SuppressWarnings("unchecked") // use runtime checks to guarantee that 'T' is what it is
+  private <T> ObjectConstructor<T> newDefaultImplementationConstructor(
+      final Type type, Class<? super T> rawType) {
+    if (Collection.class.isAssignableFrom(rawType)) {
+      if (SortedSet.class.isAssignableFrom(rawType)) {
+        return new ObjectConstructor<T>() {
+          public T construct() {
+            return (T) new TreeSet<Object>();
+          }
+        };
+      } else if (EnumSet.class.isAssignableFrom(rawType)) {
+        return new ObjectConstructor<T>() {
+          @SuppressWarnings("rawtypes")
+          public T construct() {
+            if (type instanceof ParameterizedType) {
+              Type elementType = ((ParameterizedType) type).getActualTypeArguments()[0];
+              if (elementType instanceof Class) {
+                return (T) EnumSet.noneOf((Class)elementType);
+              } else {
+                throw new JsonIOException("Invalid EnumSet type: " + type.toString());
+              }
+            } else {
+              throw new JsonIOException("Invalid EnumSet type: " + type.toString());
+            }
+          }
+        };
+      } else if (Set.class.isAssignableFrom(rawType)) {
+        return new ObjectConstructor<T>() {
+          public T construct() {
+            return (T) new LinkedHashSet<Object>();
+          }
+        };
+      } else if (Queue.class.isAssignableFrom(rawType)) {
+        return new ObjectConstructor<T>() {
+          public T construct() {
+            return (T) new LinkedList<Object>();
+          }
+        };
+      } else {
+        return new ObjectConstructor<T>() {
+          public T construct() {
+            return (T) new ArrayList<Object>();
+          }
+        };
+      }
+    }
+
+    if (Map.class.isAssignableFrom(rawType)) {
+      if (SortedMap.class.isAssignableFrom(rawType)) {
+        return new ObjectConstructor<T>() {
+          public T construct() {
+            return (T) new TreeMap<Object, Object>();
+          }
+        };
+      } else if (type instanceof ParameterizedType && !(String.class.isAssignableFrom(
+          TypeToken.get(((ParameterizedType) type).getActualTypeArguments()[0]).getRawType()))) {
+        return new ObjectConstructor<T>() {
+          public T construct() {
+            return (T) new LinkedHashMap<Object, Object>();
+          }
+        };
+      } else {
+        return new ObjectConstructor<T>() {
+          public T construct() {
+            return (T) new LinkedTreeMap<String, Object>();
+          }
+        };
+      }
+    }
+
+    return null;
+  }
+
+  private <T> ObjectConstructor<T> newUnsafeAllocator(
+      final Type type, final Class<? super T> rawType) {
+    return new ObjectConstructor<T>() {
+      private final UnsafeAllocator unsafeAllocator = UnsafeAllocator.create();
+      @SuppressWarnings("unchecked")
+      public T construct() {
+        try {
+          Object newInstance = unsafeAllocator.newInstance(rawType);
+          return (T) newInstance;
+        } catch (Exception e) {
+          throw new RuntimeException(("Unable to invoke no-args constructor for " + type + ". "
+              + "Register an InstanceCreator with Gson for this type may fix this problem."), e);
+        }
+      }
+    };
+  }
+
+  @Override public String toString() {
+    return instanceCreators.toString();
+  }
+}