add Index.getReferencedIndex for retrieving the referenced index of a foreign key index

git-svn-id: https://svn.code.sf.net/p/jackcess/code/jackcess/trunk@555 f203690c-595d-4dc9-a70b-905162fa7fd2

2 files changed, 72 insertions, 0 deletions

diff --git a/src/java/com/healthmarketscience/jackcess/Database.java b/src/java/com/healthmarketscience/jackcess/Database.java
index 3691e22..3029881 100644
--- a/src/java/com/healthmarketscience/jackcess/Database.java
+++ b/src/java/com/healthmarketscience/jackcess/Database.java
@@ -1018,6 +1018,31 @@ public class Database
   }
 
   /**
+   * @param tableDefPageNumber the page number of a table definition
+   * @return The table, or null if it doesn't exist
+   */
+  protected Table getTable(int tableDefPageNumber) throws IOException {
+
+    // first, check for existing table
+    Table table = _tableCache.get(tableDefPageNumber);
+    if(table != null) {
+      return table;
+    }
+    
+    // lookup table info from system catalog
+    Map<String,Object> objectRow = _tableFinder.getObjectRow(
+        tableDefPageNumber, SYSTEM_CATALOG_COLUMNS);
+    if(objectRow == null) {
+      return null;
+    }
+
+    String name = (String)objectRow.get(CAT_COL_NAME);
+    int flags = (Integer)objectRow.get(CAT_COL_FLAGS);
+
+    return readTable(name, tableDefPageNumber, flags, defaultUseBigIndex());
+  }
+
+  /**
    * @param name Table name
    * @param includeSystemTables whether to consider returning a system table
    * @param useBigIndex whether or not "big index support" should be enabled
diff --git a/src/java/com/healthmarketscience/jackcess/Index.java b/src/java/com/healthmarketscience/jackcess/Index.java
index c9c2bf4..532b4e1 100644
--- a/src/java/com/healthmarketscience/jackcess/Index.java
+++ b/src/java/com/healthmarketscience/jackcess/Index.java
@@ -165,6 +165,53 @@ public class Index implements Comparable<Index> {
   }
 
   /**
+   * @return the Index referenced by this Index's ForeignKeyReference (if it
+   *         has one), otherwise {@code null}.
+   */
+  public Index getReferencedIndex() throws IOException {
+
+    if(_reference == null) {
+      return null;
+    }
+
+    Table refTable = getTable().getDatabase().getTable(
+        _reference.getOtherTablePageNumber());
+
+    if(refTable == null) {
+      throw new IOException("Reference to missing table " + 
+                            _reference.getOtherTablePageNumber());
+    }
+
+    Index refIndex = null;
+    int idxNumber = _reference.getOtherIndexNumber();
+    for(Index idx : refTable.getIndexes()) {
+      if(idx.getIndexNumber() == idxNumber) {
+        refIndex = idx;
+        break;
+      }
+    }
+    
+    if(refIndex == null) {
+      throw new IOException("Reference to missing index " + idxNumber + 
+                            " on table " + refTable.getName());
+    }
+
+    // finally verify that we found the expected index (should reference this
+    // index)
+    ForeignKeyReference otherRef = refIndex.getReference();
+    if((otherRef == null) ||
+       (otherRef.getOtherTablePageNumber() != 
+        getTable().getTableDefPageNumber()) ||
+       (otherRef.getOtherIndexNumber() != _indexNumber)) {
+      throw new IOException("Found unexpected index " + refIndex.getName() +
+                            " on table " + refTable.getName() +
+                            " with reference " + otherRef);
+    }
+
+    return refIndex;
+  }
+
+  /**
    * Whether or not {@code null} values are actually recorded in the index.
    */
   public boolean shouldIgnoreNulls() {