dataholder.java

利用java反射机制

package org.julp;

    /**
     * This object holds original values from database.
     * The values are using to build UPDATE and WHERE clauses 
     */

public class DataHolder implements java.io.Serializable, Cloneable {
    
    public DataHolder() {}
    
    public DataHolder(int fieldCount) {
        this.fieldCount = fieldCount;
        data = new Object[fieldCount];
    }
    
    protected int fieldCount = 0;
    protected Object[] data = null;
    protected String[] fieldName = null;
    protected boolean ignoreWrongFieldName = false;
    
    public int getFieldCount() {
        return fieldCount;
    }
    
    public void setFieldCount(int fieldCount) {
        this.fieldCount = fieldCount;
    }
    
    public void setObject(int fieldIndex, Object value) {
        this.data[fieldIndex - 1] = value;
    }
    
    public Object getObject(int fieldIndex) {
        return this.data[fieldIndex - 1];
    }
    
    public void setFieldNameAndValue(int fieldIndex, String name, Object value) {
        this.data[fieldIndex - 1] = value;
        if (this.fieldName == null){
            this.fieldName = new String[this.fieldCount];
        }
        this.fieldName[fieldIndex - 1] = name;
    }
    
    public void setObject(String name, Object value) {
        int fieldIndex = findFieldIndex(name);
        if (fieldIndex < 0){
            if (this.fieldName == null){
                if (!ignoreWrongFieldName){
                    throw new IllegalArgumentException("Field Name not set");
                }
                System.out.println("Field Name not set");
            }else{
                if (!ignoreWrongFieldName){
                    throw new IllegalArgumentException("No such field: " + name);
                }
                System.out.println("No such field: " + name);
            }
        }
        this.data[fieldIndex - 1] = value;
    }
    
    public Object getObject(String name) {
        if (name == null){
            return null;
        }
        int fieldIndex = findFieldIndex(name);
        if (fieldIndex < 0){
            if (this.fieldName == null){
                if (!ignoreWrongFieldName){
                    throw new IllegalArgumentException("Field Name not set");
                    
                }
                return null;
            }else{
                if (!ignoreWrongFieldName){
                    throw new IllegalArgumentException("No such field: " + name);
                }
                System.out.println("No such field: " + name);
                return null;
            }
        }
        return this.data[fieldIndex - 1];
    }
    
    public void setFieldName(int fieldIndex, String name) {
        if (this.fieldName == null){
            this.fieldName = new String[this.fieldCount];
        }
        this.fieldName[fieldIndex - 1] = name;
    }
    
    public String getFieldName(int fieldIndex) {
        if (this.fieldName == null || this.fieldName.length == 0){
            return null;
        }
        return this.fieldName[fieldIndex - 1];
    }
    
    public int findFieldIndex(String name) {
        int fieldIndex = -1;
        if (this.fieldName == null || name == null){
            return fieldIndex;
        }
        for (int i = 0;i < this.fieldCount;i++){
            if (fieldName[i] == null) {
                continue;
            }
            if(fieldName[i].equals(name)){
                fieldIndex = i + 1;
                break;
            }
        }
        return fieldIndex;
    }
    
    public String toString(){
        StringBuffer sb = new StringBuffer();
        if (this.fieldName != null && this.fieldName.length == fieldCount){
            for (int i = 0;i < fieldCount;i++){
                sb.append(this.fieldName[i]).append("=");
                if (this.data[i] == null){
                }else{
                    sb.append(this.data[i]);
                }
                sb.append("&");
            }
        }else{
            for (int i = 0;i < fieldCount;i++){
                if (this.data[i] == null){
                    sb.append("null");
                }else{
                    sb.append(this.data[i]);
                }
                sb.append(",");
            }
        }
        sb.deleteCharAt(sb.length() - 1);
        return sb.toString();
    }
    
    public java.lang.Object[] getData() {
        return this.data;
    }
    
    public void setData(java.lang.Object[] data) {
        this.data = data;
    }
    
    /** Getter for property ignoreWrongFieldName.
     * @return Value of property ignoreWrongFieldName.
     *
     */
    public boolean isIgnoreWrongFieldName() {
        return ignoreWrongFieldName;
    }
    
    /** Setter for property ignoreWrongFieldName.
     * @param ignoreWrongFieldName New value of property ignoreWrongFieldName.
     *
     */
    public void setIgnoreWrongFieldName(boolean ignoreWrongFieldName) {
        this.ignoreWrongFieldName = ignoreWrongFieldName;
    }
    
}