In a bowl, combine soy, sherry, sugar, garlic, and ginger. Add chicken and stir to coat. Cover and refrigerate for one hour. Cover mushrooms with warm water, let stand for 30 minutes, then drain. Cut off and discard stems; squeeze mushrooms dry and thinly slice. Cut sausages in 1/4 inch thick diagonal slices. Drain chicken, reserving marinade; discard ginger. In a heavy 3-quart pan, heat oil over high heat. Add chicken and cook, turning, until lightly browned (about 2 minutes on each side). Remove chicken and set aside. To the pan, add reserved marinade and water; stir in rice. Bring to a boil over medium-high heat and cook, uncovered, until liquid is absorbed (about 8 to 10 minutes). Reduce heat to low and stir in chicken, sausages, and mushrooms. Cover and simmer, without stirring, until rice is tender (about 45 minutes). To serve, spoon mixture into a serving bowl and sprinkle with green onion.