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package org.codehaus.jackson.type;

import java.lang.reflect.Modifier;

/**
 * Base class for type token classes used both to contain information
 * and as keys for deserializers.
 *

* Instances can (only) be constructed by * {@link org.codehaus.jackson.map.type.TypeFactory}. */ public abstract class JavaType { /** * This is the nominal type-erased Class that would be close to the * type represented (but not exactly type, due to type erasure: type * instance may have more information on this). * May be an interface or abstract class, so instantiation * may not be possible. */ protected final Class _class; protected final int _hashCode; /** * Optional handler (codec) that can be attached to indicate * what to use for handling (serializing, deserializing) values of * this specific type. *

* Note: untyped (i.e. caller has to cast) because it is used for * different kinds of handlers, with unrelated types. *

* TODO: make final and possible promote to sub-classes * * @since 1.3 */ protected /*final*/ Object _valueHandler; /** * Optional handler that can be attached to indicate how to handle * additional type metadata associated with this type. *

* Note: untyped (i.e. caller has to cast) because it is used for * different kinds of handlers, with unrelated types. *

* TODO: make final and possible promote to sub-classes * * @since 1.5 */ protected /*final*/ Object _typeHandler; /* /********************************************************** /* Life-cycle /********************************************************** */ /** * @param raw "Raw" (type-erased) class for this type * @param additionalHash Additional hash code to use, in addition * to hash code of the class name */ protected JavaType(Class raw, int additionalHash) { _class = raw; _hashCode = raw.getName().hashCode() + additionalHash; _valueHandler = null; _typeHandler = null; } /** * "Copy method" that will construct a new instance that is identical to * this instance, except that it will have specified type handler assigned. * * @return Newly created type instance * * @since 1.7 */ public abstract JavaType withTypeHandler(Object h); /** * "Copy method" that will construct a new instance that is identical to * this instance, except that its content type will have specified * type handler assigned. * * @return Newly created type instance * * @since 1.7 */ public abstract JavaType withContentTypeHandler(Object h); // !!! TODO: in 2.0, change to be abstract method //public abstract JavaType withValueHandler(Object h); /** * @since 1.9 */ public JavaType withValueHandler(Object h) { /* 16-Aug-2011, tatu: This is not entirely correct, as we can not * create new immutable instances. However, sub-classes can, * so if mapper is version 1.9, things work as expected. * Otherwise, in 2.0 we can make this method abstract. */ setValueHandler(h); return this; } // !!! TODO: in 2.0, change to be abstract method //public abstract JavaType withContentValueHandler(Object h); /** * @since 1.9 */ public JavaType withContentValueHandler(Object h) { /* 16-Aug-2011, tatu: This is not entirely correct, as we can not * create new immutable instances. However, sub-classes can, * so if mapper is version 1.9, things work as expected. * Otherwise, in 2.0 we can make this method abstract. */ getContentType().setValueHandler(h); return this; } /** * Method for assigning handler to associate with this type; or * if null passed, to remove such assignment * * @since 1.3 * * @deprecated Since 1.9, should not be used; instead, use * withContentTypeHandler and * withContentValueHandler methods. */ @Deprecated public void setValueHandler(Object h) { // sanity check, should be assigned just once if (h != null && _valueHandler != null) { throw new IllegalStateException("Trying to reset value handler for type ["+toString() +"]; old handler of type "+_valueHandler.getClass().getName()+", new handler of type "+h.getClass().getName()); } _valueHandler = h; } /* /********************************************************** /* Type coercion fluent factory methods /********************************************************** */ /** * Method that can be called to do a "narrowing" conversions; that is, * to return a type with a raw class that is assignable to the raw * class of this type. If this is not possible, an * {@link IllegalArgumentException} is thrown. * If class is same as the current raw class, instance itself is * returned. */ public JavaType narrowBy(Class subclass) { // First: if same raw class, just return this instance if (subclass == _class) { return this; } // Otherwise, ensure compatibility _assertSubclass(subclass, _class); JavaType result = _narrow(subclass); // TODO: these checks should NOT actually be needed; above should suffice: if (_valueHandler != result.getValueHandler()) { result = result.withValueHandler(_valueHandler); } if (_typeHandler != result.getTypeHandler()) { result = result.withTypeHandler(_typeHandler); } return result; } /** * More efficient version of {@link #narrowBy}, called by * internal framework in cases where compatibility checks * are to be skipped. * * @since 1.5 */ public JavaType forcedNarrowBy(Class subclass) { if (subclass == _class) { // can still optimize for simple case return this; } JavaType result = _narrow(subclass); // TODO: these checks should NOT actually be needed; above should suffice: if (_valueHandler != result.getValueHandler()) { result = result.withValueHandler(_valueHandler); } if (_typeHandler != result.getTypeHandler()) { result = result.withTypeHandler(_typeHandler); } return result; } /** * Method that can be called to do a "widening" conversions; that is, * to return a type with a raw class that could be assigned from this * type. * If such conversion is not possible, an * {@link IllegalArgumentException} is thrown. * If class is same as the current raw class, instance itself is * returned. */ public JavaType widenBy(Class superclass) { // First: if same raw class, just return this instance if (superclass == _class) { return this; } // Otherwise, ensure compatibility _assertSubclass(_class, superclass); return _widen(superclass); } protected abstract JavaType _narrow(Class subclass); /** *

* Default implementation is just to call {@link #_narrow}, since * underlying type construction is usually identical */ protected JavaType _widen(Class superclass) { return _narrow(superclass); } public abstract JavaType narrowContentsBy(Class contentClass); /** * @since 1.8 */ public abstract JavaType widenContentsBy(Class contentClass); /* /********************************************************** /* Public API, simple accessors /********************************************************** */ public final Class getRawClass() { return _class; } /** * Method that can be used to check whether this type has * specified Class as its type erasure. Put another way, returns * true if instantiation of this Type is given (type-erased) Class. */ public final boolean hasRawClass(Class clz) { return _class == clz; } public boolean isAbstract() { return Modifier.isAbstract(_class.getModifiers()); } /** * @since 1.3 */ public boolean isConcrete() { int mod = _class.getModifiers(); if ((mod & (Modifier.INTERFACE | Modifier.ABSTRACT)) == 0) { return true; } /* 19-Feb-2010, tatus: Holy mackarel; primitive types * have 'abstract' flag set... */ if (_class.isPrimitive()) { return true; } return false; } public boolean isThrowable() { return Throwable.class.isAssignableFrom(_class); } public boolean isArrayType() { return false; } public final boolean isEnumType() { return _class.isEnum(); } public final boolean isInterface() { return _class.isInterface(); } public final boolean isPrimitive() { return _class.isPrimitive(); } public final boolean isFinal() { return Modifier.isFinal(_class.getModifiers()); } /** * @return True if type represented is a container type; this includes * array, Map and Collection types. */ public abstract boolean isContainerType(); /** * @return True if type is either true {@link java.util.Collection} type, * or something similar (meaning it has at least one type parameter, * which describes type of contents) * * @since 1.8 */ public boolean isCollectionLikeType() { return false; } /** * @return True if type is either true {@link java.util.Map} type, * or something similar (meaning it has at least two type parameter; * first one describing key type, second value type) * * @since 1.8 */ public boolean isMapLikeType() { return false; } /* /********************************************************** /* Public API, type parameter access /********************************************************** */ /** * Method that can be used to find out if the type directly declares generic * parameters (for its direct super-class and/or super-interfaces). * * @since 1.6 */ public boolean hasGenericTypes() { return containedTypeCount() > 0; } /** * Method for accessing key type for this type, assuming type * has such a concept (only Map types do) */ public JavaType getKeyType() { return null; } /** * Method for accessing content type of this type, if type has * such a thing: simple types do not, structured types do * (like arrays, Collections and Maps) */ public JavaType getContentType() { return null; } /** * Method for checking how many contained types this type * has. Contained types are usually generic types, so that * generic Maps have 2 contained types. * * @since 1.5 */ public int containedTypeCount() { return 0; } /** * Method for accessing definitions of contained ("child") * types. * * @param index Index of contained type to return * * @return Contained type at index, or null if no such type * exists (no exception thrown) * * @since 1.5 */ public JavaType containedType(int index) { return null; } /** * Method for accessing name of type variable in indicated * position. If no name is bound, will use placeholders (derived * from 0-based index); if no type variable or argument exists * with given index, null is returned. * * @param index Index of contained type to return * * @return Contained type at index, or null if no such type * exists (no exception thrown) * * @since 1.5 */ public String containedTypeName(int index) { return null; } /* /********************************************************** /* Semi-public API, accessing handlers /********************************************************** */ /** * Method for accessing value handler associated with this type, if any * * @since 1.3 */ @SuppressWarnings("unchecked") public T getValueHandler() { return (T) _valueHandler; } /** * Method for accessing type handler associated with this type, if any * * @since 1.5 */ @SuppressWarnings("unchecked") public T getTypeHandler() { return (T) _typeHandler; } /* /********************************************************** /* Support for producing signatures (1.6+) /********************************************************** */ /** * Method that can be used to serialize type into form from which * it can be fully deserialized from at a later point (using * TypeFactory from mapper package). * For simple types this is same as calling * {@link Class#getName}, but for structured types it may additionally * contain type information about contents. * * @since 1.5 */ public abstract String toCanonical(); /** * Method for accessing signature that contains generic * type information, in form compatible with JVM 1.5 * as per JLS. It is a superset of {@link #getErasedSignature}, * in that generic information can be automatically removed * if necessary (just remove outermost * angle brackets along with content inside) * * @since 1.6 */ public String getGenericSignature() { StringBuilder sb = new StringBuilder(40); getGenericSignature(sb); return sb.toString(); } /** * * @param sb StringBuilder to append signature to * * @return StringBuilder that was passed in; returned to allow * call chaining * * @since 1.6 */ public abstract StringBuilder getGenericSignature(StringBuilder sb); /** * Method for accessing signature without generic * type information, in form compatible with all versions * of JVM, and specifically used for type descriptions * when generating byte code. * * @since 1.6 */ public String getErasedSignature() { StringBuilder sb = new StringBuilder(40); getErasedSignature(sb); return sb.toString(); } /** * Method for accessing signature without generic * type information, in form compatible with all versions * of JVM, and specifically used for type descriptions * when generating byte code. * * @param sb StringBuilder to append signature to * * @return StringBuilder that was passed in; returned to allow * call chaining * * @since 1.6 */ public abstract StringBuilder getErasedSignature(StringBuilder sb); /* /********************************************************** /* Helper methods /********************************************************** */ protected void _assertSubclass(Class subclass, Class superClass) { if (!_class.isAssignableFrom(subclass)) { throw new IllegalArgumentException("Class "+subclass.getName()+" is not assignable to "+_class.getName()); } } /* /********************************************************** /* Standard methods; let's make them abstract to force override /********************************************************** */ @Override public abstract String toString(); @Override public abstract boolean equals(Object o); @Override public final int hashCode() { return _hashCode; } }





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