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Merged
bbakerman merged 2 commits into from
Nov 12, 2021
Merged

Added support for a context object to the AstTransformer #2596

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fd37964
Added support for a context object to the AstTransformer
chwrigh Oct 23, 2021
152e9b8
adding javadocs to the AstTransformer class
chwrigh Oct 23, 2021
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51 changes: 39 additions & 12 deletions src/main/java/graphql/language/AstTransformer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@
import graphql.util.TreeParallelTransformer;
import graphql.util.TreeTransformer;

import java.util.Map;
import java.util.concurrent.ForkJoinPool;

import static graphql.Assert.assertNotNull;
Expand All @@ -20,25 +21,38 @@
@PublicApi
public class AstTransformer {


/**
* Transforms the input tree using the Visitor Pattern.
* @param root the root node of the input tree.
* @param nodeVisitor the visitor which will transform the input tree.
* @return the transformed tree.
*/
public Node transform(Node root, NodeVisitor nodeVisitor) {
assertNotNull(root);
assertNotNull(nodeVisitor);

TraverserVisitor<Node> traverserVisitor = new TraverserVisitor<Node>() {
@Override
public TraversalControl enter(TraverserContext<Node> context) {
return context.thisNode().accept(context, nodeVisitor);
}
TraverserVisitor<Node> traverserVisitor = getNodeTraverserVisitor(nodeVisitor);
TreeTransformer<Node> treeTransformer = new TreeTransformer<>(AST_NODE_ADAPTER);
return treeTransformer.transform(root, traverserVisitor);
}

@Override
public TraversalControl leave(TraverserContext<Node> context) {
return TraversalControl.CONTINUE;
}
};
/**
* Transforms the input tree using the Visitor Pattern.
* @param root the root node of the input tree.
* @param nodeVisitor the visitor which will transform the input tree.
* @param rootVars a context argument to pass information into the nodeVisitor. Pass a contextual
* object to your visitor by adding it to this map such that such that the key
* is the class of the object, and the value is the object itself. The object
* can be retrieved within the visitor by calling context.getVarFromParents().
* @return the transformed tree.
*/
public Node transform(Node root, NodeVisitor nodeVisitor, Map<Class<?>, Object> rootVars) {
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@bbakerman bbakerman Oct 23, 2021

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I know the previous code did not have JavaDoc but can you please fix this up.

We now have a map of variables and hence we should explain them and how one might get access to them

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@chriswr95 chriswr95 Oct 23, 2021

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Certainly, I took a stab at writing the JavaDocs for the methods I understand. I am not sure how the parallel methods operate so I did not write JavaDocs for them.

assertNotNull(root);
assertNotNull(nodeVisitor);

TraverserVisitor<Node> traverserVisitor = getNodeTraverserVisitor(nodeVisitor);
TreeTransformer<Node> treeTransformer = new TreeTransformer<>(AST_NODE_ADAPTER);
return treeTransformer.transform(root, traverserVisitor);
return treeTransformer.transform(root, traverserVisitor, rootVars);
}

public Node transformParallel(Node root, NodeVisitor nodeVisitor) {
Expand All @@ -61,4 +75,17 @@ public TraversalControl enter(TraverserContext<Node> context) {
return treeParallelTransformer.transform(root, traverserVisitor);
}

private TraverserVisitor<Node> getNodeTraverserVisitor(NodeVisitor nodeVisitor) {
return new TraverserVisitor<Node>() {
@Override
public TraversalControl enter(TraverserContext<Node> context) {
return context.thisNode().accept(context, nodeVisitor);
}

@Override
public TraversalControl leave(TraverserContext<Node> context) {
return TraversalControl.CONTINUE;
}
};
}
}
29 changes: 29 additions & 0 deletions src/test/groovy/graphql/language/AstTransformerTest.groovy
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Expand Up @@ -322,6 +322,35 @@ class AstTransformerTest extends Specification {

}

def "delete node through context"() {
def document = TestUtil.parseQuery("{root { a(arg: 1) { x y } toDelete { x y } } }")

final Map<Class<?>, Object> rootVars = new LinkedHashMap<>();
rootVars.put(String.class, "toDelete");

AstTransformer astTransformer = new AstTransformer()

def visitor = new NodeVisitorStub() {

@Override
TraversalControl visitField(Field field, TraverserContext<Node> context) {
final String fieldToDelete = context.getVarFromParents(String.class);
if (field.name == fieldToDelete) {
return deleteNode(context);
} else {
return TraversalControl.CONTINUE;
}
}
}

when:
def newDocument = astTransformer.transform(document, visitor, rootVars)

then:
printAstCompact(newDocument) == "query {root {a(arg:1) {x y}}}"

}

def "delete node parallel"() {
def document = TestUtil.parseQuery("{root { a(arg: 1) { x y } toDelete { x y } } }")

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