com.yahoo.slime.Injector Maven / Gradle / Ivy
// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.slime;
/**
* @author hakonhall
*/
public class Injector {
/**
* Inject a slime sub-structure described by an Inspector into a slime
* structure where the insertion point is described by an
* Inserter. This will copy all the values represented by the
* Inspector into the position described by the Inserter. Note that
* this can be used to either copy data from one Slime structure to
* another, or to copy data internally within a single slime
* structure. If the Inspector contains the insertion point it will
* only be expanded once to avoid infinite recursion.
*
* @param inspector what to inject
* @param inserter where to inject
*/
public void inject(Inspector inspector, Inserter inserter) {
if (inspector.valid()) {
injectValue(inserter, inspector, null);
}
}
private void injectValue(Inserter inserter, Inspector inspector, Inspector guard) {
inspector.accept(new Visitor() {
@Override public void visitInvalid() { }
@Override public void visitNix() { inserter.insertNIX(); }
@Override public void visitBool(boolean bit) { inserter.insertBOOL(bit); }
@Override public void visitLong(long l) { inserter.insertLONG(l); }
@Override public void visitDouble(double d) { inserter.insertDOUBLE(d); }
@Override public void visitString(String str) { inserter.insertSTRING(str); }
@Override public void visitString(byte[] utf8) { inserter.insertSTRING(utf8); }
@Override public void visitData(byte[] data) { inserter.insertDATA(data); }
@Override
public void visitArray(Inspector arr) {
Cursor cursor = inserter.insertARRAY();
ArrayTraverser arrayTraverser = new NestedInjector(cursor, guard != null ? guard : cursor);
arr.traverse(arrayTraverser);
}
@Override
public void visitObject(Inspector obj) {
Cursor cursor = inserter.insertOBJECT();
ObjectTraverser objectTraverser = new NestedInjector(cursor, guard != null ? guard : cursor);
obj.traverse(objectTraverser);
}
});
}
private class NestedInjector implements ArrayTraverser, ObjectTraverser {
private final Cursor cursor;
private final Inspector guard;
public NestedInjector(Cursor cursor, Inspector guard) {
this.cursor = cursor;
this.guard = guard;
}
@Override
public void entry(int idx, Inspector inspector) {
if (inspector == guard) {
return;
}
injectValue(new ArrayInserter(cursor), inspector, guard);
}
@Override
public void field(String name, Inspector inspector) {
if (inspector == guard) {
return;
}
injectValue(new ObjectInserter(cursor, name), inspector, guard);
}
}
}