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| 1 | +/* |
| 2 | + * Hibernate, Relational Persistence for Idiomatic Java |
| 3 | + * |
| 4 | + * License: GNU Lesser General Public License (LGPL), version 2.1 or later. |
| 5 | + * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>. |
| 6 | + */ |
| 7 | +package org.hibernate.jpamodelgen.util; |
| 8 | + |
| 9 | +import java.util.List; |
| 10 | +import javax.lang.model.element.Element; |
| 11 | +import javax.lang.model.element.ElementKind; |
| 12 | +import javax.lang.model.element.TypeParameterElement; |
| 13 | +import javax.lang.model.type.ArrayType; |
| 14 | +import javax.lang.model.type.DeclaredType; |
| 15 | +import javax.lang.model.type.ExecutableType; |
| 16 | +import javax.lang.model.type.IntersectionType; |
| 17 | +import javax.lang.model.type.NoType; |
| 18 | +import javax.lang.model.type.NullType; |
| 19 | +import javax.lang.model.type.PrimitiveType; |
| 20 | +import javax.lang.model.type.TypeKind; |
| 21 | +import javax.lang.model.type.TypeMirror; |
| 22 | +import javax.lang.model.type.TypeVariable; |
| 23 | +import javax.lang.model.type.UnionType; |
| 24 | +import javax.lang.model.type.WildcardType; |
| 25 | +import javax.lang.model.util.SimpleTypeVisitor8; |
| 26 | + |
| 27 | +/** |
| 28 | + * @author Christian Beikov |
| 29 | + */ |
| 30 | +public final class TypeRenderingVisitor extends SimpleTypeVisitor8<Object, Object> { |
| 31 | + |
| 32 | + private final StringBuilder sb = new StringBuilder(); |
| 33 | + |
| 34 | + private TypeRenderingVisitor() { |
| 35 | + } |
| 36 | + |
| 37 | + public static String toString(TypeMirror typeMirror) { |
| 38 | + if ( typeMirror instanceof TypeVariable ) { |
| 39 | + // Top level type variables don't need to render the upper bound as `T extends Type` |
| 40 | + final Element typeVariableElement = ( (TypeVariable) typeMirror ).asElement(); |
| 41 | + if ( typeVariableElement instanceof TypeParameterElement ) { |
| 42 | + final TypeParameterElement typeParameter = (TypeParameterElement) typeVariableElement; |
| 43 | + if ( typeParameter.getEnclosingElement().getKind() == ElementKind.METHOD ) { |
| 44 | + // But for method level type variable we return the upper bound |
| 45 | + // because the type variable has no meaning except for that method |
| 46 | + typeMirror = ( (TypeVariable) typeMirror ).getUpperBound(); |
| 47 | + } |
| 48 | + else { |
| 49 | + return typeParameter.toString(); |
| 50 | + } |
| 51 | + } |
| 52 | + else { |
| 53 | + typeMirror = typeVariableElement.asType(); |
| 54 | + } |
| 55 | + } |
| 56 | + else if ( typeMirror instanceof IntersectionType ) { |
| 57 | + // For top level type only the first type is relevant |
| 58 | + typeMirror = ( (IntersectionType) typeMirror ).getBounds().get( 0 ); |
| 59 | + } |
| 60 | + final TypeRenderingVisitor typeRenderingVisitor = new TypeRenderingVisitor(); |
| 61 | + typeMirror.accept( typeRenderingVisitor, null ); |
| 62 | + return typeRenderingVisitor.sb.toString(); |
| 63 | + } |
| 64 | + |
| 65 | + @Override |
| 66 | + public Object visitPrimitive(PrimitiveType t, Object o) { |
| 67 | + final String primitiveTypeName = getPrimitiveTypeName( t.getKind() ); |
| 68 | + if ( primitiveTypeName != null ) { |
| 69 | + sb.append( primitiveTypeName ); |
| 70 | + } |
| 71 | + return null; |
| 72 | + } |
| 73 | + |
| 74 | + private static String getPrimitiveTypeName(TypeKind kind) { |
| 75 | + switch ( kind ) { |
| 76 | + case INT: |
| 77 | + return "int"; |
| 78 | + case BOOLEAN: |
| 79 | + return "boolean"; |
| 80 | + case BYTE: |
| 81 | + return "byte"; |
| 82 | + case CHAR: |
| 83 | + return "char"; |
| 84 | + case DOUBLE: |
| 85 | + return "double"; |
| 86 | + case FLOAT: |
| 87 | + return "float"; |
| 88 | + case LONG: |
| 89 | + return "long"; |
| 90 | + case SHORT: |
| 91 | + return "short"; |
| 92 | + case VOID: |
| 93 | + return "void"; |
| 94 | + } |
| 95 | + return null; |
| 96 | + } |
| 97 | + |
| 98 | + @Override |
| 99 | + public Object visitNull(NullType t, Object o) { |
| 100 | + return null; |
| 101 | + } |
| 102 | + |
| 103 | + @Override |
| 104 | + public Object visitArray(ArrayType t, Object o) { |
| 105 | + t.getComponentType().accept( this, null ); |
| 106 | + sb.append( "[]" ); |
| 107 | + return t; |
| 108 | + } |
| 109 | + |
| 110 | + @Override |
| 111 | + public Object visitDeclared(DeclaredType t, Object o) { |
| 112 | + sb.append( t.asElement().toString() ); |
| 113 | + List<? extends TypeMirror> typeArguments = t.getTypeArguments(); |
| 114 | + if ( !typeArguments.isEmpty() ) { |
| 115 | + sb.append( '<' ); |
| 116 | + typeArguments.get( 0 ).accept( this, null ); |
| 117 | + for ( int i = 1; i < typeArguments.size(); i++ ) { |
| 118 | + sb.append( ", " ); |
| 119 | + typeArguments.get( i ).accept( this, null ); |
| 120 | + } |
| 121 | + sb.append( '>' ); |
| 122 | + } |
| 123 | + return null; |
| 124 | + } |
| 125 | + |
| 126 | + @Override |
| 127 | + public Object visitTypeVariable(TypeVariable t, Object o) { |
| 128 | + final Element typeVariableElement = t.asElement(); |
| 129 | + if ( typeVariableElement instanceof TypeParameterElement ) { |
| 130 | + final TypeParameterElement typeParameter = (TypeParameterElement) typeVariableElement; |
| 131 | + sb.append( typeParameter ); |
| 132 | + if ( !"java.lang.Object".equals( t.getUpperBound().toString() ) ) { |
| 133 | + sb.append( " extends " ); |
| 134 | + t.getUpperBound().accept( this, null ); |
| 135 | + } |
| 136 | + } |
| 137 | + else { |
| 138 | + typeVariableElement.asType().accept( this, null ); |
| 139 | + } |
| 140 | + return null; |
| 141 | + } |
| 142 | + |
| 143 | + @Override |
| 144 | + public Object visitWildcard(WildcardType t, Object o) { |
| 145 | + sb.append( '?' ); |
| 146 | + if ( t.getExtendsBound() != null ) { |
| 147 | + sb.append( " extends " ); |
| 148 | + t.getExtendsBound().accept( this, null ); |
| 149 | + } |
| 150 | + if ( t.getSuperBound() != null ) { |
| 151 | + sb.append( " super " ); |
| 152 | + t.getSuperBound().accept( this, null ); |
| 153 | + } |
| 154 | + return null; |
| 155 | + } |
| 156 | + |
| 157 | + @Override |
| 158 | + public Object visitUnion(UnionType t, Object o) { |
| 159 | + return null; |
| 160 | + } |
| 161 | + |
| 162 | + @Override |
| 163 | + public Object visitIntersection(IntersectionType t, Object o) { |
| 164 | + final List<? extends TypeMirror> bounds = t.getBounds(); |
| 165 | + bounds.get( 0 ).accept( this, null ); |
| 166 | + for ( int i = 0; i < bounds.size(); i++ ) { |
| 167 | + sb.append( " & " ); |
| 168 | + bounds.get( i ).accept( this, null ); |
| 169 | + } |
| 170 | + return null; |
| 171 | + } |
| 172 | + |
| 173 | + @Override |
| 174 | + public Object visitExecutable(ExecutableType t, Object o) { |
| 175 | + return null; |
| 176 | + } |
| 177 | + |
| 178 | + @Override |
| 179 | + public Object visitNoType(NoType t, Object o) { |
| 180 | + return null; |
| 181 | + } |
| 182 | +} |
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