Java tutorial
/* * This file is part of JGAP. * * JGAP offers a dual license model containing the LGPL as well as the MPL. * * For licensing information please see the file license.txt included with JGAP * or have a look at the top of class org.jgap.Chromosome which representatively * includes the JGAP license policy applicable for any file delivered with JGAP. */ package org.jgap.gp.function; import org.apache.commons.lang.builder.*; import org.jgap.*; import org.jgap.gp.*; import org.jgap.gp.impl.*; import org.jgap.util.*; /** * The for-loop. You can preset the start index and the end index. If the latter * is not given, it is dynamically computed from a child. * * @author Klaus Meffert * @since 3.0 */ public class ForLoop extends CommandGene implements ICloneable { /** String containing the CVS revision. Read out via reflection!*/ private final static String CVS_REVISION = "$Revision: 1.20 $"; private static String INTERNAL_COUNTER_STORAGE = "FORLOOPSTORAGE_INT"; private Class m_typeVar; private int m_startIndex; private int m_endIndex; private int m_increment; private int m_maxLoop; private String m_memory_name_int; private String m_varName; /** * Constructor. * * @param a_conf the configuration to use * @param a_typeVar Class of the loop counter terminakl (e.g. IntegerClass) * @param a_maxLoop the maximum number of loops to perform * @throws InvalidConfigurationException * * @author Klaus Meffert * @since 3.0 */ public ForLoop(final GPConfiguration a_conf, Class a_typeVar, int a_maxLoop) throws InvalidConfigurationException { this(a_conf, a_typeVar, 0, a_maxLoop); } /** * Constructor allowing to preset the starting index of the loop. * * @param a_conf the configuration to use * @param a_typeVar Class of the loop counter terminakl (e.g. IntegerClass) * @param a_startIndex index to start the loop with (normally 0) * @param a_maxLoop the maximum number of loops to perform * @throws InvalidConfigurationException * * @author Klaus Meffert * @since 3.0 */ public ForLoop(final GPConfiguration a_conf, Class a_typeVar, int a_startIndex, int a_maxLoop) throws InvalidConfigurationException { this(a_conf, a_typeVar, a_startIndex, a_maxLoop, "i"); } public ForLoop(final GPConfiguration a_conf, Class a_typeVar, int a_startIndex, int a_maxLoop, String a_varName) throws InvalidConfigurationException { super(a_conf, 2, CommandGene.VoidClass); m_typeVar = a_typeVar; m_maxLoop = a_maxLoop; m_startIndex = a_startIndex; m_endIndex = -1; m_increment = 1; m_varName = a_varName; init(); } /** * Constructor allowing to preset the starting and the ending index of the * loop. * * @param a_conf the configuration to use * @param a_typeVar Class of the loop counter terminal (e.g. IntegerClass) * @param a_startIndex index to start the loop with * @param a_endIndex index to end the loop with * @param a_increment the maximum number of loops to perform * @param a_varName informal textual name of the loop counter variable * @throws InvalidConfigurationException * * @author Klaus Meffert * @since 3.2 */ public ForLoop(final GPConfiguration a_conf, Class a_typeVar, int a_startIndex, int a_endIndex, int a_increment, String a_varName) throws InvalidConfigurationException { this(a_conf, a_typeVar, a_startIndex, a_endIndex, a_increment, a_varName, 0, 0); } public ForLoop(final GPConfiguration a_conf, Class a_typeVar, int a_startIndex, int a_endIndex, int a_increment, String a_varName, int a_subReturnType, int a_subChildType) throws InvalidConfigurationException { super(a_conf, 1, CommandGene.VoidClass, a_subReturnType, a_subChildType); m_typeVar = a_typeVar; m_increment = a_increment; m_startIndex = a_startIndex; m_endIndex = a_endIndex; m_varName = a_varName; init(); } protected void init() { super.init(); // Generate unique name. // --------------------- m_memory_name_int = INTERNAL_COUNTER_STORAGE; m_memory_name_int += m_varName; m_memory_name_int += getGPConfiguration().getRandomGenerator().nextInt(); } public String toString() { if (m_endIndex == -1) { return "for(int i=" + m_startIndex + ";i<&1;i++) { &2 }"; } else { String incrString; if (m_increment == 1) { incrString = m_varName + "++"; } else { incrString = m_varName + "=" + m_varName + "+1"; } return "for(int " + m_varName + "=" + m_startIndex + ";" + m_varName + "<" + m_endIndex + ";" + incrString + ") { &1 }"; } } /** * @return textual name of this command * * @author Klaus Meffert * @since 3.2 */ public String getName() { return "ForLoop"; } public Object execute_object(ProgramChromosome c, int n, Object[] args) { StringBuffer value = new StringBuffer(); value = value.append("for(int " + m_varName + "=" + m_startIndex + ";" + m_varName + "<" + m_endIndex + ";" + m_varName + "++) {"); for (int i = 0; i < size(); i++) { value = value.append((StringBuffer) c.execute_object(n, i, args)); } value = value.append("}"); return value; } public void execute_void(ProgramChromosome c, int n, Object[] args) { // Determine the end index of the loop (child at index 0). // ------------------------------------------------------- int x; if (m_endIndex == -1) { if (m_typeVar == CommandGene.IntegerClass) { x = c.execute_int(n, 0, args); } else if (m_typeVar == CommandGene.LongClass) { x = (int) c.execute_long(n, 0, args); } else if (m_typeVar == CommandGene.DoubleClass) { x = (int) Math.round(c.execute_double(n, 0, args)); } else if (m_typeVar == CommandGene.FloatClass) { x = (int) Math.round(c.execute_float(n, 0, args)); } else { throw new RuntimeException("Type " + m_typeVar + " not supported by ForLoop"); } if (x > m_maxLoop) { x = m_maxLoop; } // Repeatedly execute the second child (index = 1). // ------------------------------------------------ for (int i = m_startIndex; i < x; i++) { c.execute_void(n, 1, args); } } else { // Repeatedly execute the first child (index = 0). // ----------------------------------------------- for (int i = m_startIndex; i < m_endIndex; i = i + m_increment) { // Store counter in memory. // ------------------------ getGPConfiguration().storeInMemory(ForLoop.INTERNAL_COUNTER_STORAGE, new Integer(i)); c.execute_void(n, 0, args); } } } public boolean isValid(ProgramChromosome a_program) { return true; } public Class getChildType(IGPProgram a_ind, int a_chromNum) { if (m_endIndex == -1) { // Variant A: dynamic end index if (a_chromNum == 0) { // Loop counter variable. // ---------------------- return m_typeVar; } else { // Subprogram. // ----------- return CommandGene.VoidClass; } } else { // Variant B: fixed end index return CommandGene.VoidClass; } } /** * @return symbolic name of the variable name used in the for header. * * @author Klaus Meffert * @since 3.4 */ public String getVarName() { return m_varName; } /** * The compareTo-method. * * @param a_other the other object to compare * @return -1, 0, 1 * * @author Klaus Meffert * @since 3.0 */ public int compareTo(Object a_other) { int result = super.compareTo(a_other); if (result != 0) { return result; } ForLoop other = (ForLoop) a_other; return new CompareToBuilder().append(m_typeVar, other.m_typeVar).append(m_maxLoop, other.m_maxLoop) .append(m_startIndex, other.m_startIndex).append(m_endIndex, other.m_endIndex) .append(m_increment, other.m_increment).toComparison(); } /** * The equals-method. * * @param a_other the other object to compare * @return true if the objects are seen as equal * * @author Klaus Meffert * @since 3.0 */ public boolean equals(Object a_other) { try { ForLoop other = (ForLoop) a_other; return super.equals(a_other) && new EqualsBuilder().append(m_typeVar, other.m_typeVar) .append(m_maxLoop, other.m_maxLoop).append(m_startIndex, other.m_startIndex) .append(m_endIndex, other.m_endIndex).append(m_increment, other.m_increment).isEquals(); } catch (ClassCastException cex) { return false; } } /** * @return name of the memory cell where the current value of the loop * variable is stored * * @author Klaus Meffert * @since 3.2 */ public String getCounterMemoryName() { return m_memory_name_int; } /** * Clones the object. Simple and straight forward implementation here. * * @return cloned instance of this object * * @author Klaus Meffert * @since 3.4 */ public Object clone() { try { ForLoop result; if (getArity(null) == 1) { result = new ForLoop(getGPConfiguration(), m_typeVar, m_startIndex, m_endIndex, m_increment, m_varName, getSubReturnType(), getSubChildType(0)); } else { result = new ForLoop(getGPConfiguration(), m_typeVar, m_startIndex, m_maxLoop, m_varName); } return result; } catch (Exception ex) { throw new CloneException(ex); } } }