@Override
    public boolean equals(Object o) {
        if (o == this) return true;
        if ( ! (o instanceof Schema other)) return false;
        if ( ! other.name.equals(this.name)) return false;
        if ( ! other.fields.equals(this.fields)) return false;
        if ( ! other.fieldSets.equals(this.fieldSets)) return false;
        if ( ! other.rankProfiles.equals(this.rankProfiles)) return false;
        if ( ! other.documentSummaries.equals(this.documentSummaries)) return false;
        return true;
    }
Looks up a field or field set by the given name or alias in this schema.

@param fieldName the name or alias of the field or field set. If this is empty, the name "default" is looked up
@return information about the field or field set with the given name, or empty if no item with this name exists
container-search/src/main/java/com/yahoo/search/schema/Schema.java