#1214 - ENH: Add inPairs() expression - support L2 cache hits for complex natural key with findList() and in pairs expression

src/main/java/io/ebeaninternal/server/expression/InPairsExpression.java

@@ -0,0 +1,142 @@
+package io.ebeaninternal.server.expression;
+
+import io.ebean.Pairs;
+import io.ebean.event.BeanQueryRequest;
+import io.ebeaninternal.api.NaturalKeyQueryData;
+import io.ebeaninternal.api.SpiExpression;
+import io.ebeaninternal.api.SpiExpressionRequest;
+import io.ebeaninternal.server.persist.MultiValueWrapper;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+class InPairsExpression extends AbstractExpression {
+
+  private final boolean not;
+
+  private final Pairs pairs;
+
+  private final String property0, property1;
+
+  private final List<Pairs.Entry> entries;
+
+  private boolean multiValueSupported;
+
+  private final String separator;
+
+  private final String suffix;
+
+  private List<Object> concatBindValues;
+
+  InPairsExpression(Pairs pairs, boolean not) {
+    super(pairs.getProperty0());
+    this.pairs = pairs;
+    this.property0 = pairs.getProperty0();
+    this.property1 = pairs.getProperty1();
+    this.entries = pairs.getEntries();
+    this.not = not;
+    this.separator = pairs.getConcatSeparator();
+    this.suffix = pairs.getConcatSuffix();
+  }
+
+  @Override
+  public boolean naturalKey(NaturalKeyQueryData data) {
+    return !not && data.matchInPairs(pairs);
+  }
+
+  @Override
+  public void prepareExpression(BeanQueryRequest<?> request) {
+
+    // at this stage translating pairs into varchar via DB concat
+    multiValueSupported = request.isMultiValueSupported(String.class);
+  }
+
+  @Override
+  public void writeDocQuery(DocQueryContext context) throws IOException {
+    throw new RuntimeException("Not supported with document query");
+  }
+
+  @Override
+  public void addBindValues(SpiExpressionRequest request) {
+
+    // Note at this point entries may have been removed when used with l2 caching
+    // ... for each l2 cache hit an entry was removed
+    this.concatBindValues = new ArrayList<>(entries.size());
+    for (Pairs.Entry entry : entries) {
+      concatBindValues.add(concat(entry.getA(), entry.getB()));
+    }
+    request.addBindValue(new MultiValueWrapper(concatBindValues, String.class));
+  }
+
+  /**
+   * Using DB concat at this stage. Usually a DB expression index should match the concat.
+   */
+  private String concat(Object key, Object value) {
+    StringBuilder sb = new StringBuilder(30);
+    sb.append(key);
+    sb.append(separator);
+    sb.append(value);
+    if (suffix != null) {
+      sb.append(suffix);
+    }
+    return sb.toString();
+  }
+
+  @Override
+  public void addSql(SpiExpressionRequest request) {
+
+    if (entries.isEmpty()) {
+      String expr = not ? "1=1" : "1=0";
+      request.append(expr);
+      return;
+    }
+
+    String concat = request.getDbPlatformHandler().getConcatOperator();
+
+    String concatFormula = "(" + property0 + concat + "'" + separator + "'" + concat + property1;
+    if (suffix != null && !suffix.isEmpty()) {
+      concatFormula += concat + "'" + suffix + "'";
+    }
+    concatFormula += ")";
+    request.append(concatFormula);
+    request.appendInExpression(not, concatBindValues);
+  }
+
+  /**
+   * Based on the number of values in the in clause.
+   */
+  @Override
+  public void queryPlanHash(StringBuilder builder) {
+    if (not) {
+      builder.append("NotInPairs[");
+    } else {
+      builder.append("InPairs[");
+    }
+    builder.append(property0).append("-");
+    builder.append(property1).append("-");
+    builder.append(separator).append("-");
+    builder.append(suffix).append(" ?");
+    if (!multiValueSupported) {
+      // query plan specific to the number of parameters in the IN clause
+      builder.append(entries.size());
+    }
+    builder.append("]");
+  }
+
+  @Override
+  public int queryBindHash() {
+    int hc = 92821;
+    for (Pairs.Entry entry : entries) {
+      hc = 92821 * hc + entry.hashCode();
+    }
+    return hc;
+  }
+
+  @Override
+  public boolean isSameByBind(SpiExpression other) {
+
+    InPairsExpression that = (InPairsExpression) other;
+    return this.entries.size() == that.entries.size() && entries.equals(that.entries);
+  }
+}