Initial commit

git-svn-id: https://joinup.ec.europa.eu/svn/moa-idspss/trunk@2 d688527b-c9ab-4aba-bd8d-4036d912da1d

1 files changed, 61 insertions, 0 deletions

diff --git a/spss.server/src/at/gv/egovernment/moa/spss/server/util/IdGenerator.java b/spss.server/src/at/gv/egovernment/moa/spss/server/util/IdGenerator.java
new file mode 100644
index 000000000..92e8cb0f8
--- /dev/null
+++ b/spss.server/src/at/gv/egovernment/moa/spss/server/util/IdGenerator.java
@@ -0,0 +1,61 @@
+package at.gv.egovernment.moa.spss.server.util;
+
+import java.util.Set;
+
+/**
+ * Generate unique ID values for various objects in the response.
+ * 
+ * @author Patrick Peck
+ * @version $Id$
+ */
+public class IdGenerator {
+  /** The base value to append the counter to. */
+  private String base;
+  /** The <code>Set</code> of reserved ID values. */
+  private Set reserved;
+  /** The sequence number. */
+  private int count;
+  
+  /**
+   * Create a new <code>IdGenerator</code>.
+   * 
+   * @param base A base value to append the IDs to. The creator of this object
+   * should provide a base value, so that appending the counter leads to unique
+   * IDs.
+   * @param reserved The <code>Set</code> of reserved IDs. A call to 
+   * <code>uniqueId()</code> will respect the reserved IDs.
+   */
+  public IdGenerator(String base, Set reserved) {
+    this.base = base;
+    this.reserved = reserved;
+    count = 1;
+  }
+  
+  /**
+   * Create the next ID value in the sequence.
+   * 
+   * @return The next ID value in the sequence.
+   */
+  public String nextId() {
+    return base + "-" + count++;
+  }
+  
+  /**
+   * Create the next unique ID value which is unique in the reserved ID set.
+   * 
+   * The created ID is added to the set of reserved IDs.
+   * 
+   * @return The next ID value.
+   */
+  public String uniqueId() {
+    String nextId;
+
+    while (reserved.contains(nextId = nextId()));
+    
+    reserved.add(nextId);
+    
+    return nextId;
+        
+  }
+  
+}