X-Git-Url: http://jsfdemo.indexdata.com/?a=blobdiff_plain;f=src%2Fmain%2Fjava%2Fcom%2Findexdata%2Fmkjsf%2Fpazpar2%2Fcommands%2FExpression.java;h=1961baeef111c2fa5ed27dabc2e2eeb72af2c435;hb=fc1ac55e0dd989bc3a5a023c5931e8f4e2774668;hp=f636f68a7a172abce519b4dccd26bc33fa731922;hpb=875d04a7c3120b7c4b3a412985957df15479ff81;p=mkjsf-moved-to-github.git

diff --git a/src/main/java/com/indexdata/mkjsf/pazpar2/commands/Expression.java b/src/main/java/com/indexdata/mkjsf/pazpar2/commands/Expression.java
index f636f68..1961bae 100644
--- a/src/main/java/com/indexdata/mkjsf/pazpar2/commands/Expression.java
+++ b/src/main/java/com/indexdata/mkjsf/pazpar2/commands/Expression.java
@@ -4,6 +4,22 @@ import java.io.Serializable;
 
 import org.apache.log4j.Logger;
 
+/**
+ * Represents a complex command parameter value, in form of an expression with 
+ * an equality operator
+ * <p>
+ * An expression consist of a left-of-operator field or key, an equality operator (= or ~), 
+ * a right-of-operator value, and optionally a label describing the value for UI display.
+ * </p> 
+ * <p>Examples:</p>
+ * <ul>
+ *  <li><code>pz:id=1234</code> "My Target"</li>
+ *  <li><code>category~libcatalog</code> "Library Catalogs"</li>
+ *  <li><code>author="Steinbeck, John"</code></li>
+ * </ul>
+ * @author Niels Erik
+ *
+ */
 public class Expression implements Serializable {
   
   private static final long serialVersionUID = -751704027842027769L;
@@ -13,13 +29,31 @@ public class Expression implements Serializable {
   String rightEntity;
   String label;  
   
-  public Expression (String leftEntity, String operator, String rightEntity, String label) {
-    this.leftEntity = leftEntity;
+  /**
+   * Instantiates an expression with a label
+   * 
+   * @param leftEntity left-of-operator field name (or 'key')
+   * @param operator an equality operator
+   * @param rightEntity right-of-operator value
+   * @param label to be used for display, for instance in a UI control that adds or removes the expression
+   *  from a command parameter
+   */
+  public Expression (String field, String operator, String value, String label) {
+    this.leftEntity = field;
     this.operator = operator;
-    this.rightEntity = rightEntity;    
+    this.rightEntity = value;    
     this.label = label;
   }
   
+  /**
+   * Instantiates an expression by parsing the provided expression string, which must be
+   * on the form {name}({=}or{~}){value}.
+   * <p>
+   * Currently only '=' and '~' are recognized as operators
+   * </p>
+   * 
+   * @param expressionString
+   */
   public Expression (String expressionString) {
     String[] parts = expressionString.split("[=~]");
     this.leftEntity = parts[0];
@@ -28,6 +62,11 @@ public class Expression implements Serializable {
     this.label=rightEntity;
   }
   
+  /** 
+   * Clones the expression
+   * 
+   * @return a clone of this expression
+   */
   public Expression copy() {
     logger.trace("Copying " + this.toString());
     return new Expression(leftEntity, operator, rightEntity, label);
@@ -37,18 +76,39 @@ public class Expression implements Serializable {
     return leftEntity + operator + rightEntity;
   }
   
+  /**
+   * Returns the label describing the value of the expression or,
+   * if no label was provided, the value itself.
+   * 
+   * @return label or right-of-operator value if no label provided
+   */
   public String getLabel() {
     return label;
   }
   
+  /**
+   * Returns the left-of-operator field (or name or key).
+   * 
+   * @return entity left of operator
+   */
   public String getField () {
     return leftEntity;
   }
   
+  /**
+   * Returns the operator 
+   * 
+   * @return the operator of the expression
+   */
   public String getOperator() {
     return operator;
   }
   
+  /**
+   * Returns the right-of-operator value of the expression
+   * 
+   * @return entity right of operator
+   */
   public String getValue() {
     return rightEntity;
   }