/**
* Creates a new {@link SpelExpressionOutput} for the given field, SpEL expression and
* parameters.
*
* @param expression must not be {@literal null} or empty.
* @param parameters must not be {@literal null}.
*/
public SpelExpressionOutput(String expression, Object[] parameters) {
super(Fields.field(expression));
Assert.hasText(expression, "Expression must not be null!");
Assert.notNull(parameters, "Parameters must not be null!");
this.expression = expression;
this.params = parameters.clone();
}
/**
* Creates a new {@link Output} for the given field.
*
* @param operation the actual operation key, must not be {@literal null} or empty.
* @param values the values to pass into the operation, must not be {@literal null}.
*/
public OperationOutput(String operation, Collection<? extends Object> values) {
super(Fields.field(operation));
Assert.hasText(operation, "Operation must not be null or empty!");
Assert.notNull(values, "Values must not be null!");
this.operation = operation;
this.values = new ArrayList<Object>(values);
}
@Override
public final void fromArray(Object[] array, Field<?>... f) {
Fields accept = new Fields(f);
int size = fields.size();
for (int i = 0; i < size && i < array.length; i++) {
Field field = fields.field(i);
if (accept.field(field) != null) {
Utils.setValue(this, field, array[i]);
}
}
}
/**
* Returns the finally to be applied {@link BucketOperation} with the given alias.
*
* @param alias will never be {@literal null} or empty.
* @return
*/
public T as(String alias) {
if (value instanceof OperationOutput) {
return this.operation.andOutput(((OperationOutput) this.value).withAlias(alias));
}
if (value instanceof Field) {
throw new IllegalStateException(
"Cannot add a field as top-level output. Use accumulator expressions.");
}
return this.operation.andOutput(
new AggregationExpressionOutput(Fields.field(alias), (AggregationExpression) value));
}
/**
* Creates a new instance of this {@link OperationOutput} with the given alias.
*
* @param alias the alias to set
* @return
*/
public OperationOutput withAlias(String alias) {
final Field aliasedField = Fields.field(alias);
return new OperationOutput(aliasedField, this) {
@Override
protected Field getField() {
return aliasedField;
}
@Override
protected List<Object> getOperationArguments(AggregationOperationContext context) {
// We have to make sure that we use the arguments from the "previous" OperationOutput that
// we replace
// with this new instance.
return OperationOutput.this.getOperationArguments(context);
}
};
}
@Override
public final Field<?> field(int index) {
return fields.field(index);
}
@Override
public final Field<?> field(String name) {
return fields.field(name);
}
@Override
public final <T> Field<T> field(Field<T> field) {
return fields.field(field);
}