1 files changed, 59 insertions, 0 deletions
diff --git a/javaparser-core-generators/src/main/java/com/github/javaparser/generator/core/visitor/HashCodeVisitorGenerator.java b/javaparser-core-generators/src/main/java/com/github/javaparser/generator/core/visitor/HashCodeVisitorGenerator.java
new file mode 100644
index 000000000..554dc8d9d
--- /dev/null
+++ b/javaparser-core-generators/src/main/java/com/github/javaparser/generator/core/visitor/HashCodeVisitorGenerator.java
@@ -0,0 +1,59 @@
+package com.github.javaparser.generator.core.visitor;
+
+import com.github.javaparser.ast.CompilationUnit;
+import com.github.javaparser.ast.body.MethodDeclaration;
+import com.github.javaparser.ast.stmt.BlockStmt;
+import com.github.javaparser.generator.VisitorGenerator;
+import com.github.javaparser.utils.SeparatedItemStringBuilder;
+import com.github.javaparser.utils.SourceRoot;
+import com.github.javaparser.metamodel.BaseNodeMetaModel;
+import com.github.javaparser.metamodel.PropertyMetaModel;
+
+import java.util.List;
+
+import static com.github.javaparser.JavaParser.parseStatement;
+
+/**
+ * Generates JavaParser's HashCodeVisitor.
+ */
+public class HashCodeVisitorGenerator extends VisitorGenerator {
+    public HashCodeVisitorGenerator(SourceRoot sourceRoot) {
+        super(sourceRoot, "com.github.javaparser.ast.visitor", "HashCodeVisitor", "Integer", "Void", true);
+    }
+
+    @Override
+    protected void generateVisitMethodBody(BaseNodeMetaModel node, MethodDeclaration visitMethod, CompilationUnit compilationUnit) {
+        visitMethod.getParameters().forEach(p -> p.setFinal(true));
+
+        final BlockStmt body = visitMethod.getBody().get();
+        body.getStatements().clear();
+
+        final SeparatedItemStringBuilder builder = new SeparatedItemStringBuilder("return ", "* 31 +", ";");
+        final List<PropertyMetaModel> propertyMetaModels= node.getAllPropertyMetaModels();
+        if (propertyMetaModels.isEmpty()) {
+            builder.append("0");
+        } else {
+            for (PropertyMetaModel field : propertyMetaModels) {
+                final String getter = field.getGetterMethodName() + "()";
+                // Is this field another AST node? Visit it.
+                if (field.getNodeReference().isPresent()) {
+                    if (field.isOptional()) {
+                        builder.append("(n.%s.isPresent()? n.%s.get().accept(this, arg):0)", getter, getter);
+                    } else {
+                        builder.append("(n.%s.accept(this, arg))", getter);
+                    }
+                } else {
+                    Class<?> type = field.getType();
+                    if (type.equals(boolean.class)) {
+                        builder.append("(n.%s?1:0)", getter);
+                    } else if (type.equals(int.class)) {
+                        builder.append("n.%s", getter);
+                    } else {
+                        builder.append("(n.%s.hashCode())", getter);
+                    }
+                }
+            }
+        }
+        body.addStatement(parseStatement(builder.toString()));
+    }
+}