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src/main/java/com/imprimelibros/erp/datatables/DataTablesSpecification.java

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+package com.imprimelibros.erp.datatables;
+
+import org.springframework.data.jpa.domain.Specification;
+import jakarta.persistence.criteria.*;
+import java.util.ArrayList;
+import java.util.List;
+
+public class DataTablesSpecification {
+
+    /**
+     * Crea una Specification con búsqueda global y por columna (LIKE case-insensitive)
+     * @param dt   request de datatables
+     * @param searchableFields campos del entity para el buscador global
+     */
+    public static <T> Specification<T> build(DataTablesRequest dt, List<String> searchableFields) {
+        return (root, query, cb) -> {
+            List<Predicate> ands = new ArrayList<>();
+
+            // Filtro por columna (si quieres soportarlo)
+            for (int i = 0; i < dt.columns.size(); i++) {
+                DataTablesRequest.Column col = dt.columns.get(i);
+                if (col.searchable && col.search != null && col.search.value != null && !col.search.value.isEmpty()) {
+                    ands.add(like(cb, root.get(col.name), col.search.value));
+                }
+            }
+
+            // Búsqueda global
+            if (dt.search != null && dt.search.value != null && !dt.search.value.isEmpty() && !searchableFields.isEmpty()) {
+                String term = "%" + dt.search.value.trim().toLowerCase() + "%";
+                List<Predicate> ors = new ArrayList<>();
+                for (String f : searchableFields) {
+                    ors.add(cb.like(cb.lower(root.get(f).as(String.class)), term));
+                }
+                ands.add(cb.or(ors.toArray(new Predicate[0])));
+            }
+
+            return ands.isEmpty() ? cb.conjunction() : cb.and(ands.toArray(new Predicate[0]));
+        };
+    }
+
+    private static Predicate like(CriteriaBuilder cb, Path<?> path, String value) {
+        return cb.like(cb.lower(path.as(String.class)), "%" + value.trim().toLowerCase() + "%");
+    }
+}