implemented CtField#getConstantValue().

git-svn-id: http://anonsvn.jboss.org/repos/javassist/trunk@128 30ef5769-5b8d-40dd-aea6-55b5d6557bb3

src/main/javassist/CtField.java

@@ -244,6 +244,42 @@ public class CtField extends CtMember {
         fieldInfo.setDescriptor(Descriptor.of(clazz));
     }
 
+    /**
+     * Returns the value of this field if it is a constant field.
+     * This method works only if the field type is a primitive type
+     * or <code>String</code> type.  Otherwise, it returns <code>null</code>.
+     * A constant field is <code>static</code> and <code>final</code>.
+     *
+     * @return  a <code>Integer</code>, <code>Long</code>, <code>Float</code>,
+     *          <code>Double</code>, or <code>String</code> object
+     *          representing the constant value. 
+     *          <code>null</code> if it is not a constant field
+     *          or if the field type is not a primitive type
+     *          or <code>String</code>.
+     */
+    public Object getConstantValue() {
+        int index = fieldInfo.getConstantValue();
+        if (index == 0)
+            return null;
+
+        ConstPool cp = fieldInfo.getConstPool();
+        switch (cp.getTag(index)) {
+            case ConstPool.CONST_Long :
+                return new Long(cp.getLongInfo(index));
+            case ConstPool.CONST_Float :
+                return new Float(cp.getFloatInfo(index));
+            case ConstPool.CONST_Double :
+                return new Double(cp.getDoubleInfo(index));
+            case ConstPool.CONST_Integer :
+                return new Integer(cp.getIntegerInfo(index));
+            case ConstPool.CONST_String :
+                return cp.getStringInfo(index);
+            default :
+                throw new RuntimeException("bad tag: " + cp.getTag(index)
+                                           + " at " + index);
+        }
+    }
+
     /**
      * Obtains an attribute with the given name.
      * If that attribute is not found in the class file, this

src/main/javassist/bytecode/ConstPool.java

@@ -68,7 +68,7 @@ public final class ConstPool {
     /**
      * <code>CONSTANT_Float</code>
      */
-    public static final int CONST_Float = IntegerInfo.tag;
+    public static final int CONST_Float = FloatInfo.tag;
 
     /**
      * <code>CONSTANT_Long</code>

src/main/javassist/bytecode/FieldInfo.java

@@ -60,7 +60,15 @@ public final class FieldInfo {
     }
 
     void prune(ConstPool cp) {
-        attribute = null;
+        int index = getConstantValue();
+        if (index == 0)
+            attribute = null;
+        else {
+            index = constPool.copy(index, cp, null);
+            attribute = new LinkedList();
+            attribute.add(new ConstantAttribute(cp, index));
+        }
+
         name = cp.addUtf8Info(getName());
         descriptor = cp.addUtf8Info(getDescriptor());
         constPool = cp;
@@ -125,6 +133,24 @@ public final class FieldInfo {
             descriptor = constPool.addUtf8Info(desc);
     }
 
+    /**
+     * Finds a ConstantValue attribute and returns the index into
+     * the <code>constant_pool</code> table.
+     *
+     * @return 0    if a ConstantValue attribute is not found.
+     */
+    public int getConstantValue() {
+        if ((accessFlags & AccessFlag.STATIC) == 0)
+            return 0;
+
+        ConstantAttribute attr
+            = (ConstantAttribute)getAttribute(ConstantAttribute.tag);
+        if (attr == null)
+            return 0;
+        else
+            return attr.getConstantValue();
+    }
+
     /**
      * Returns all the attributes.
      * A new element can be added to the returned list

src/main/javassist/compiler/ast/CastExpr.java

@@ -47,6 +47,8 @@ public class CastExpr extends ASTList implements TokenId {
 
     public ASTree getOprand() { return getRight().getLeft(); }
 
+    public void setOprand(ASTree t) { getRight().setLeft(t); }
+
     public String getTag() { return "cast:" + castType + ":" + arrayDim; }
 
     public void accept(Visitor v) throws CompileError { v.atCastExpr(this); }

src/main/javassist/compiler/ast/CondExpr.java

@@ -27,6 +27,8 @@ public class CondExpr extends ASTList {
 
     public ASTree condExpr() { return head(); }
 
+    public void setCond(ASTree t) { setHead(t); }
+
     public ASTree thenExpr() { return tail().head(); }
 
     public void setThen(ASTree t) { tail().setHead(t); } 

src/main/javassist/compiler/ast/DoubleConst.java

@@ -16,6 +16,7 @@
 package javassist.compiler.ast;
 
 import javassist.compiler.CompileError;
+import javassist.compiler.TokenId;
 
 /**
  * Double constant.
@@ -28,6 +29,8 @@ public class DoubleConst extends ASTree {
 
     public double get() { return value; }
 
+    public void set(double v) { value = v; }
+
     /* Returns DoubleConstant or FloatConstant
      */
     public int getType() { return type; }
@@ -37,4 +40,55 @@ public class DoubleConst extends ASTree {
     public void accept(Visitor v) throws CompileError {
         v.atDoubleConst(this);
     }
+
+    public ASTree compute(int op, ASTree right) {
+        if (right instanceof IntConst)
+            return compute0(op, (IntConst)right);
+        else if (right instanceof DoubleConst)
+            return compute0(op, (DoubleConst)right);
+        else
+            return null;
+    }
+
+    private DoubleConst compute0(int op, DoubleConst right) {
+        int newType;
+        if (this.type == TokenId.DoubleConstant
+            || right.type == TokenId.DoubleConstant)
+            newType = TokenId.DoubleConstant;
+        else
+            newType = TokenId.FloatConstant;
+
+        return compute(op, this.value, right.value, newType);
+    }
+
+    private DoubleConst compute0(int op, IntConst right) {
+        return compute(op, this.value, (double)right.value, this.type);
+    }
+
+    private static DoubleConst compute(int op, double value1, double value2,
+                                       int newType)
+    {
+        double newValue;
+        switch (op) {
+        case '+' :
+            newValue = value1 + value2;
+            break;
+        case '-' :
+            newValue = value1 - value2;
+            break;
+        case '*' :
+            newValue = value1 * value2;
+            break;
+        case '/' :
+            newValue = value1 / value2;
+            break;
+        case '%' :
+            newValue = value1 % value2;
+            break;
+        default :
+            return null;
+        }
+
+        return new DoubleConst(newValue, newType);
+    }
 }

src/main/javassist/compiler/ast/Expr.java

@@ -52,6 +52,10 @@ public class Expr extends ASTList implements TokenId {
 
     public ASTree oprand1() { return getLeft(); }
 
+    public void setOprand1(ASTree expr) {
+        setLeft(expr);
+    }
+
     public ASTree oprand2() { return getRight().getLeft(); }
 
     public void setOprand2(ASTree expr) {

src/main/javassist/compiler/ast/IntConst.java

@@ -16,6 +16,7 @@
 package javassist.compiler.ast;
 
 import javassist.compiler.CompileError;
+import javassist.compiler.TokenId;
 
 /**
  * Integer constant.
@@ -28,6 +29,8 @@ public class IntConst extends ASTree {
 
     public long get() { return value; }
 
+    public void set(long v) { value = v; }
+
     /* Returns IntConstant, CharConstant, or LongConstant.
      */
     public int getType() { return type; }
@@ -37,4 +40,99 @@ public class IntConst extends ASTree {
     public void accept(Visitor v) throws CompileError {
         v.atIntConst(this);
     }
+
+    public ASTree compute(int op, ASTree right) {
+        if (right instanceof IntConst)
+            return compute0(op, (IntConst)right);
+        else if (right instanceof DoubleConst)
+            return compute0(op, (DoubleConst)right);
+        else
+            return null;
+    }
+
+    private IntConst compute0(int op, IntConst right) {
+        int type1 = this.type;
+        int type2 = right.type;
+        int newType;
+        if (type1 == TokenId.LongConstant || type2 == TokenId.LongConstant)
+            newType = TokenId.LongConstant;
+        else if (type1 == TokenId.CharConstant
+                 && type2 == TokenId.CharConstant)
+            newType = TokenId.CharConstant;
+        else
+            newType = TokenId.IntConstant;
+
+        long value1 = this.value;
+        long value2 = right.value;
+        long newValue;
+        switch (op) {
+        case '+' :
+            newValue = value1 + value2;
+            break;
+        case '-' :
+            newValue = value1 - value2;
+            break;
+        case '*' :
+            newValue = value1 * value2;
+            break;
+        case '/' :
+            newValue = value1 / value2;
+            break;
+        case '%' :
+            newValue = value1 % value2;
+            break;
+        case '|' :
+            newValue = value1 | value2;
+            break;
+        case '^' :
+            newValue = value1 ^ value2;
+            break;
+        case '&' :
+            newValue = value1 & value2;
+            break;
+        case TokenId.LSHIFT :
+            newValue = value << (int)value2;
+            newType = type1;
+            break;
+        case TokenId.RSHIFT :
+            newValue = value >> (int)value2;
+            newType = type1;
+            break;
+        case TokenId.ARSHIFT :
+            newValue = value >>> (int)value2;
+            newType = type1;
+            break;
+        default :
+            return null;
+        }
+
+        return new IntConst(newValue, newType);
+    }
+
+    private DoubleConst compute0(int op, DoubleConst right) {
+        double value1 = (double)this.value;
+        double value2 = right.value;
+        double newValue;
+        switch (op) {
+        case '+' :
+            newValue = value1 + value2;
+            break;
+        case '-' :
+            newValue = value1 - value2;
+            break;
+        case '*' :
+            newValue = value1 * value2;
+            break;
+        case '/' :
+            newValue = value1 / value2;
+            break;
+        case '%' :
+            newValue = value1 % value2;
+            break;
+        default :
+            return null;
+        }
+
+        return new DoubleConst(newValue, right.type);
+    }
 }