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package com.sun.tools.xjc.generator.bean.field;
import java.util.List;
import com.sun.codemodel.JBlock;
import com.sun.codemodel.JClass;
import com.sun.codemodel.JExpr;
import com.sun.codemodel.JExpression;
import com.sun.codemodel.JFieldRef;
import com.sun.codemodel.JFieldVar;
import com.sun.codemodel.JMethod;
import com.sun.codemodel.JMod;
import com.sun.codemodel.JOp;
import com.sun.codemodel.JPrimitiveType;
import com.sun.codemodel.JType;
import com.sun.tools.xjc.generator.bean.ClassOutlineImpl;
import com.sun.tools.xjc.model.CPropertyInfo;
/**
* Common code for property renderer that generates a List as
* its underlying data structure.
*
*
* For performance reasons, the actual list object used to store
* data is lazily created.
*
* @author
* Kohsuke Kawaguchi ([email protected])
*/
abstract class AbstractListField extends AbstractField {
/** The field that stores the list. */
protected JFieldVar field;
/**
* a method that lazily initializes a List.
* Lazily created.
*
* [RESULT]
* List _getFoo() {
* if(field==null)
* field = create new list;
* return field;
* }
*/
private JMethod internalGetter;
/**
* If this collection property is a collection of a primitive type,
* this variable refers to that primitive type.
* Otherwise null.
*/
protected final JPrimitiveType primitiveType;
protected final JClass listT = codeModel.ref(List.class).narrow(exposedType.boxify());
/**
* True to create a new instance of List eagerly in the constructor.
* False otherwise.
*
*
* Setting it to true makes the generated code slower (as more list instances need to be
* allocated), but it works correctly if the user specifies the custom type of a list.
*/
private final boolean eagerInstanciation;
/**
* Call {@link #generate()} method right after this.
*/
protected AbstractListField(ClassOutlineImpl outline, CPropertyInfo prop, boolean eagerInstanciation) {
super(outline,prop);
this.eagerInstanciation = eagerInstanciation;
if( implType instanceof JPrimitiveType ) {
// primitive types don't have this tricky distinction
assert implType==exposedType;
primitiveType = (JPrimitiveType)implType;
} else
primitiveType = null;
}
protected final void generate() {
// for the collectionType customization to take effect, the field needs to be strongly typed,
// not just List.
field = outline.implClass.field( JMod.PROTECTED, listT, prop.getName(false) );
if(eagerInstanciation)
field.init(newCoreList());
annotate(field);
// generate the rest of accessors
generateAccessors();
}
private void generateInternalGetter() {
internalGetter = outline.implClass.method(JMod.PROTECTED,listT,"_get"+prop.getName(true));
if(!eagerInstanciation) {
// if eagerly instanciated, the field can't be null
fixNullRef(internalGetter.body());
}
internalGetter.body()._return(field);
}
/**
* Generates statement(s) so that the successive {@link Accessor#ref(boolean)} with
* true will always return a non-null list.
*
* This is useful to avoid generating redundant internal getter.
*/
protected final void fixNullRef(JBlock block) {
block._if(field.eq(JExpr._null()))._then()
.assign(field,newCoreList());
}
public JType getRawType() {
return codeModel.ref(List.class).narrow(exposedType.boxify());
}
private JExpression newCoreList() {
return JExpr._new(getCoreListType());
}
/**
* Concrete class that implements the List interface.
* Used as the actual data storage.
*/
protected abstract JClass getCoreListType();
/** Generates accessor methods. */
protected abstract void generateAccessors();
/**
*
*
* @author
* Kohsuke Kawaguchi ([email protected])
*/
protected abstract class Accessor extends AbstractField.Accessor {
/**
* Reference to the {@link AbstractListField#field}
* of the target object.
*/
protected final JFieldRef field;
protected Accessor( JExpression $target ) {
super($target);
field = $target.ref(AbstractListField.this.field);
}
protected final JExpression unbox( JExpression exp ) {
if(primitiveType==null) return exp;
else return primitiveType.unwrap(exp);
}
protected final JExpression box( JExpression exp ) {
if(primitiveType==null) return exp;
else return primitiveType.wrap(exp);
}
/**
* Returns a reference to the List field that stores the data.
*
* Using this method hides the fact that the list is lazily
* created.
*
* @param canBeNull
* if true, the returned expression may be null (this is
* when the list is still not constructed.) This could be
* useful when the caller can deal with null more efficiently.
* When the list is null, it should be treated as if the list
* is empty.
*
* if false, the returned expression will never be null.
* This is the behavior users would see.
*/
protected final JExpression ref(boolean canBeNull) {
if(canBeNull)
return field;
if(internalGetter==null)
generateInternalGetter();
return $target.invoke(internalGetter);
}
public JExpression count() {
return JOp.cond( field.eq(JExpr._null()), JExpr.lit(0), field.invoke("size") );
}
public void unsetValues( JBlock body ) {
body.assign(field,JExpr._null());
}
public JExpression hasSetValue() {
return field.ne(JExpr._null()).cand(field.invoke("isEmpty").not());
}
}
}