adding binding for json to cql predicates

adapter-cqld4/src/main/java/io/nosqlbench/datamappers/functions/hdf_to_cql/HdfPredicatesToCql.java

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+/*
+ * Copyright (c) 2024 nosqlbench
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package io.nosqlbench.datamappers.functions.hdf_to_cql;
+
+import io.jhdf.HdfFile;
+import io.jhdf.api.Dataset;
+import io.nosqlbench.nb.api.nbio.NBIO;
+import io.nosqlbench.virtdata.api.annotations.Categories;
+import io.nosqlbench.virtdata.api.annotations.Category;
+import io.nosqlbench.virtdata.api.annotations.ThreadSafeMapper;
+import io.nosqlbench.virtdata.predicates.JsonPredicateSerDes;
+import io.nosqlbench.virtdata.predicates.ast.PConjunction;
+import io.nosqlbench.virtdata.predicates.ast.PredicateExpr;
+import io.nosqlbench.virtdata.predicates.ast.PredicateTerm;
+import io.nosqlbench.virtdata.predicates.types.PredicateAdapter;
+import io.nosqlbench.virtdata.predicates.types.PredicateSerDes;
+
+import java.util.function.LongFunction;
+import java.util.stream.Collectors;
+
+/**
+ * Binding function that accepts a long input value for the cycle and returns a string consisting of the
+ * CQL predicate parsed from a single record in an HDF5 dataset
+ */
+@ThreadSafeMapper
+@Categories(Category.experimental)
+public class HdfPredicatesToCql implements LongFunction<String>, PredicateAdapter {
+    private final HdfFile hdfFile;
+    private final Dataset dataset;
+    private final int recordCount;
+    private final PredicateSerDes serDes;
+
+    /**
+     * Create a new binding function that accepts a long input value for the cycle and returns a string
+     * @param filename The HDF5 file to read the predicate dataset from
+     * @param datasetname The name of the dataset internal to the HDRF5 file
+     */
+    public HdfPredicatesToCql(String filename, String datasetname) {
+        hdfFile = new HdfFile(NBIO.all().search(filename).one().asPath());
+        dataset = hdfFile.getDatasetByPath(datasetname);
+        recordCount = dataset.getDimensions()[0];
+        //TODO: -- use spi service loader interface for serDes implementation
+        serDes = new JsonPredicateSerDes();
+    }
+
+    @Override
+    public String apply(long l) {
+        long[] sliceOffset = {(l % recordCount)};
+        int[] sliceDimensions = {1};
+        return getPredicate(serDes.unserialize(((String[])dataset.getData(sliceOffset, sliceDimensions))[0]));
+    }
+
+    @Override
+    public String getPredicate(PredicateExpr model) {
+        return switch (model.getConjunction()) {
+            case PConjunction.none -> renderTerm(model);
+            case PConjunction.and -> renderTermsAnd(model);
+            case PConjunction.or -> renderTermsOr(model);
+        };
+    }
+
+    private String renderTerm(PredicateExpr pe) {
+        PredicateTerm pt = pe.getTerms().getFirst();
+        return pt.field.name + " " + pt.operator.name() + " " + pt.comparator.value;
+    }
+
+    private String renderTermsAnd(PredicateExpr pae) {
+        return pae.getTerms().stream().map(this::renderTerm).collect(Collectors.joining(" and "));
+    }
+
+    private String renderTermsOr(PredicateExpr poe) {
+        return poe.getTerms().stream().map(this::renderTerm).collect(Collectors.joining(" or "));
+    }
+}