| 1 | package dk.deepthought.sidious.supportsystem; |
| 2 | |
| 3 | import java.util.ArrayList; |
| 4 | import java.util.Collection; |
| 5 | |
| 6 | import org.apache.commons.logging.Log; |
| 7 | import org.apache.commons.logging.LogFactory; |
| 8 | |
| 9 | import dk.deepthought.sidious.explanation.Explanation; |
| 10 | |
| 11 | /** |
| 12 | * This class represents a list of <code>Adjustable</code> objects and their |
| 13 | * setting. |
| 14 | * |
| 15 | * @author Deepthought |
| 16 | * |
| 17 | */ |
| 18 | public class Step { |
| 19 | |
| 20 | /** |
| 21 | * The logger for this class. |
| 22 | */ |
| 23 | private static final Log logger = LogFactory.getLog(Step.class); |
| 24 | |
| 25 | /** |
| 26 | * The adjustables of this. |
| 27 | */ |
| 28 | private final Collection<Adjustable> adjustables; |
| 29 | |
| 30 | /** |
| 31 | * The explanation of this. |
| 32 | */ |
| 33 | private Explanation explanation; |
| 34 | |
| 35 | /** |
| 36 | * Constructs a new <code>Step</code> object, specified by the input |
| 37 | * <code>adjustables</code>. |
| 38 | * <p> |
| 39 | * The input adjustables are copied defensively. |
| 40 | * <p> |
| 41 | * If the input collection is <code>null</code> an empty step is created. |
| 42 | * This is to facilitate graphs that do not utilize steps. |
| 43 | * |
| 44 | * @param adjustables |
| 45 | * adjustables associated with this step |
| 46 | */ |
| 47 | public Step(final Collection<Adjustable> adjustables) { |
| 48 | if (logger.isDebugEnabled()) { |
| 49 | logger.debug("Step(Collection<Adjustable> adjustables=" |
| 50 | + adjustables + ")"); |
| 51 | } |
| 52 | if (adjustables != null) { |
| 53 | this.adjustables = new ArrayList<Adjustable>(adjustables); |
| 54 | if (adjustables.isEmpty()) { |
| 55 | String fail = "Empty adjustable list not allowed"; |
| 56 | logger.error(fail); |
| 57 | throw new IllegalArgumentException(fail); |
| 58 | } |
| 59 | } else { |
| 60 | this.adjustables = new ArrayList<Adjustable>(); |
| 61 | } |
| 62 | } |
| 63 | |
| 64 | /** |
| 65 | * Returns all possible steps emanating from this step. |
| 66 | * <p> |
| 67 | * The possible steps are calculated by collecting and combining all |
| 68 | * possible adjustments of all adjustables of this step. |
| 69 | * |
| 70 | * @return all possible steps emanating from this step |
| 71 | */ |
| 72 | public Collection<Step> getSteps() { |
| 73 | if (logger.isDebugEnabled()) { |
| 74 | logger.debug("getSteps() - start"); |
| 75 | } |
| 76 | Collection<Step> steps = new ArrayList<Step>(); |
| 77 | ArrayList<Adjustable> proxyAdjustables = new ArrayList<Adjustable>( |
| 78 | adjustables); |
| 79 | for (Adjustable adj : adjustables) { |
| 80 | proxyAdjustables.remove(adj); |
| 81 | Collection<Adjustable> resultingAdjustables = adj |
| 82 | .possibleAdjustments(); |
| 83 | for (Adjustable newAdj : resultingAdjustables) { |
| 84 | proxyAdjustables.add(newAdj); |
| 85 | steps.add(new Step(proxyAdjustables)); |
| 86 | proxyAdjustables.remove(newAdj); |
| 87 | } |
| 88 | proxyAdjustables.add(adj); |
| 89 | } |
| 90 | if (logger.isDebugEnabled()) { |
| 91 | logger.debug("getSteps() - returned " + steps.size() |
| 92 | + " new possible steps"); |
| 93 | } |
| 94 | steps.add(this);// "virgin" step |
| 95 | return steps; |
| 96 | } |
| 97 | |
| 98 | /** |
| 99 | * Calculates the consequence of applying the adjustments of this step to |
| 100 | * the input state. |
| 101 | * |
| 102 | * @param state |
| 103 | * the input state |
| 104 | * @return the calculated consequence |
| 105 | */ |
| 106 | public State consequence(State state) { |
| 107 | if (logger.isDebugEnabled()) { |
| 108 | logger.debug("consequence(State state=" + state + ") - start"); |
| 109 | } |
| 110 | if (state == null) { |
| 111 | return null; |
| 112 | } |
| 113 | Collection<State> states = new ArrayList<State>(); |
| 114 | for (Adjustable adj : adjustables) { |
| 115 | states.add(adj.consequence(state)); |
| 116 | } |
| 117 | State returnState = state.impact(states); |
| 118 | if (logger.isDebugEnabled()) { |
| 119 | logger.debug("consequence(State state=" + state |
| 120 | + ") - end - return value=" + returnState); |
| 121 | } |
| 122 | return returnState; |
| 123 | } |
| 124 | |
| 125 | /** |
| 126 | * Returns the adjustables of this step. |
| 127 | * |
| 128 | * @return the adjustables of this step |
| 129 | */ |
| 130 | public Collection<Adjustable> getAdjustables() { |
| 131 | return new ArrayList<Adjustable>(adjustables); |
| 132 | } |
| 133 | |
| 134 | /** |
| 135 | * Sets the explanation of this. |
| 136 | * |
| 137 | * @param explanation |
| 138 | * the explanation |
| 139 | */ |
| 140 | public void setExplanation(Explanation explanation) { |
| 141 | this.explanation = explanation; |
| 142 | } |
| 143 | |
| 144 | /** |
| 145 | * Gets the explanation of this. |
| 146 | * |
| 147 | * @return the explanation |
| 148 | */ |
| 149 | public Explanation getExplanation() { |
| 150 | return explanation; |
| 151 | } |
| 152 | |
| 153 | /* |
| 154 | * (non-Javadoc) |
| 155 | * |
| 156 | * @see java.lang.Object#hashCode() |
| 157 | */ |
| 158 | @Override |
| 159 | public int hashCode() { |
| 160 | final int PRIME = 31; |
| 161 | int result = 1; |
| 162 | result = PRIME * result |
| 163 | + ((adjustables == null) ? 0 : adjustables.hashCode()); |
| 164 | |
| 165 | return result; |
| 166 | } |
| 167 | |
| 168 | /* |
| 169 | * (non-Javadoc) |
| 170 | * |
| 171 | * @see java.lang.Object#equals(java.lang.Object) |
| 172 | */ |
| 173 | @Override |
| 174 | public boolean equals(Object obj) { |
| 175 | if (this == obj) { |
| 176 | return true; |
| 177 | } |
| 178 | if (obj == null) { |
| 179 | return false; |
| 180 | } |
| 181 | if (getClass() != obj.getClass()) { |
| 182 | return false; |
| 183 | } |
| 184 | final Step other = (Step) obj; |
| 185 | if (adjustables == null) { |
| 186 | if (other.adjustables != null) { |
| 187 | return false; |
| 188 | } |
| 189 | } else if (!adjustables.equals(other.adjustables)) { |
| 190 | return false; |
| 191 | } |
| 192 | return true; |
| 193 | } |
| 194 | |
| 195 | /* |
| 196 | * (non-Javadoc) |
| 197 | * |
| 198 | * @see java.lang.Object#toString() |
| 199 | */ |
| 200 | @Override |
| 201 | public String toString() { |
| 202 | return getClass().getSimpleName() + "[adjustables=" + adjustables |
| 203 | + ", explanation=" + explanation + "]"; |
| 204 | } |
| 205 | |
| 206 | } |